Biology | Popular Science https://www.popsci.com/category/biology/ Awe-inspiring science reporting, technology news, and DIY projects. Skunks to space robots, primates to climates. That's Popular Science, 145 years strong. Tue, 28 Nov 2023 17:00:00 +0000 en-US hourly 1 https://wordpress.org/?v=6.2.2 https://www.popsci.com/uploads/2021/04/28/cropped-PSC3.png?auto=webp&width=32&height=32 Biology | Popular Science https://www.popsci.com/category/biology/ 32 32 Female Taricha newts are more poisonous than males https://www.popsci.com/environment/female-newts-poison/ Tue, 28 Nov 2023 17:00:00 +0000 https://www.popsci.com/?p=592705
An orange California newt sits on a rock. The amphibians are endemic to California.
California newts are endemic to California. They live through the coast and coast range mountains from Mendocino County to San Diego County. Adam Clause/University of Georgia

Tetrodotoxin is more than a poison. It may also be a mating signal.

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An orange California newt sits on a rock. The amphibians are endemic to California.
California newts are endemic to California. They live through the coast and coast range mountains from Mendocino County to San Diego County. Adam Clause/University of Georgia

The newts of the genus Taricha come armed with a powerful neurotoxin that they excrete from their skin called tetrodotoxin. The toxin is a chemical defense used against predators. In a study published November 28 in the journal Frontiers in Amphibian and Reptile Science, a team of biologists describes how female Taricha newts produce more tetrodotoxin than males. The findings suggest that tetrodotoxin is not only a line of defense, but also a kind of signal. 

[Related: Poisonous animals probably took their sweet time developing unappetizing bright colors.]

“It had long been considered that newts’ toxin concentrations do not change in their lifetime and that males and females tend to have the same toxin concentrations. Now, we have shown that female newts actually contain more toxin than male newts,” study co-author and University of California, Davis ecologist and evolutionary biologist Gary Bucciarelli said in a statement. “We observed significantly greater and more drastically fluctuating toxin concentrations in females, which may have numerous causes, like mate selection.”  

Totally toxic traits

Tetrodotoxin is also found in the deadly blue-ringed octopus, pufferfish, and some shellfish and amphibian species. In sexually reproducing animals, sexually dimorphic traits like canine tooth size and vibrant color can be a key to reproductive fitness and their survival. These differing traits are believed to increase an individual’s chances of producing the next generation of offspring.

Scientists already knew that Taricha newts had other sexually dimorphic traits, such as mass, size, and tail height, so they were curious to see if toxin production also differed between the sexes. 

In the study, the authors took tetrodotoxin samples from more than 850 newts across 38 different sites in California. They noted the sex, size, mass, and tail height for all of the animals, and if the female newts were pregnant. The newts that had been captured and released were also marked so that they could know if they had been previously sampled. 

Next, the team analyzed their skin to quantify how much of the toxin was found in males compared to females. They also looked at the relationship between sexually dimorphic variables  like size and tail height and how toxin levels changed at the study sites where they could sample more than once across the breeding season. 

Understanding how these toxins work could help biologists understand more about the newts’ reproductive strategies and aid in conservation measures. A recent study found that two out of five amphibians are threatened with extinction and they continue to be the most threatened class of vertebrates on Earth. 

Femme fatale

The authors found that the females carried more toxins than the male newts. While tetrodotoxin levels generally fluctuated in both sexes, the change in females’ levels of toxin was larger. This means that female newts are likely more dangerous than males. 

[Related: How we can help the most endangered class of animals survive climate change.]

“For would-be predators, these higher concentrations pose a serious threat,” said Bucciarelli. “Taricha newts should not be handled unless by knowledgeable personnel, because they can contain up [to] 54 milligrams of tetrodotoxin per individual. Doses up to 42 micrograms per kilo of bodyweight can lead to hospitalization or death.”

The tetrodotoxin also appeared to interact with some of the other sexually dimorphic traits. The heavier newts produced higher levels of the toxin than the lighter newts and the median concentration of toxin was always higher in females regardless of size or weight. The physical resources needed to produce the toxin are possibly invested differently by females than males. Their skin may also be able to carry more of the toxin.

The higher levels of tetrodotoxin might protect females that are vulnerable to predators while reproducing. It could also allow the females to transfer toxin-producing bacteria to their eggs to potentially protect their offspring from snakes. 

Poison patterns

Previously, tetrodotoxin was believed to just be a defense against snakes. The differing amount between the sexes suggests that there might be more to it. The aroma due to the higher concentrations of the toxin may be a cue that helps the newts decide where they look for mates and which mates they choose. 

Taricha newts’ breeding patterns are highly dependent on precipitation patterns. Given the drought conditions of California, we did not always have a balanced design when field sampling,” said Bucciarelli. “However, we feel the pattern is still very strong. Our next plan is to explore how drought and fire affect newts and their toxin concentrations and how each sex responds to these natural disasters.”

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A critically endangered Sumatran rhino named Delilah welcomes first calf https://www.popsci.com/environment/sumatran-rhino-calf-born/ Mon, 27 Nov 2023 19:00:00 +0000 https://www.popsci.com/?p=592458
A newborn rhino calf stands under his mother. He is black and does not have his signature horns in yet.
The new arrival is the fifth calf born at the Way Kambas Sanctuary and second in 2023. Indonesian Ministry of Environment and Forestry

The species is critically endangered, with fewer than 50 animals left.

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A newborn rhino calf stands under his mother. He is black and does not have his signature horns in yet.
The new arrival is the fifth calf born at the Way Kambas Sanctuary and second in 2023. Indonesian Ministry of Environment and Forestry

On November 25, a healthy male Sumatran rhinoceros was born at a western Indonesian sanctuary. This birth is welcome news for the critically endangered species. There are less than 50 Sumatran rhinos left, according to the World Wildlife Fund (WWF) and the International Union for Conservation of Nature (IUCN).

[Related: Rhino horns are shrinking, and humans are to blame.]

A seven-year-old female rhino named Delilah gave birth to the 55 pound calf at the Sumatran Rhino Sanctuary in Way Kambas National Park (SRS TNWK) on the island of Sumatra. According to officials from the sanctuary, a conservation guard found her laying next to her calf early on Saturday morning. The birth was about 10 days before the baby’s expected due date. The baby’s father is a rhino named Harapan who was born at the Cincinnati Zoo and Botanical Garden in Ohio before coming to Sumatra. 

“You never know if a first-time mom will know what to do, but Delilah brought that calf into the world and started nursing it with no fuss or fanfare. It’s an incredible event that gives hope to the future of this critically endangered species,” International Rhino Foundation executive director Nina Fascione said in a press release

A newborn rhino lays on the ground with its eyes open. It is black and does not have its horns in yet.
The male calf was born roughly 10 days early. CREDIT: Indonesian Ministry of Environment and Forestry

Sumatran rhinos are the smallest of all rhino species at about 1,000 to 2,100 pounds and three to four feet tall. They have two horns that are dark gray to black. The horns are usually very smooth and form a slender cone that is curved backwards in the wild. Poaching, illegal trading of rhino horns, and climate change have pushed these mammals to the brink of extinction. According to the IUCN Red List, they are currently extinct in Bangladesh, Bhutan, Brunei, Cambodia, India, Laos, Malaysia, Thailand, and Vietnam, according to the Red List. It is uncertain if they are still present in Myanmar. 

Successful births like this one are also rare. In 2012, a male rhino named Andatu born at Way Kambas became the first Sumatran rhino born in an Indonesian sanctuary in over 120 years.

“Two years ago there was only one captive Sumatran rhino pair in the world able to successfully produce offspring. Now there are three pairs–six rhinos–who are proven breeders. Those are much better odds for the long-term survival of this species,” said Fascione.

According to Indonesian Environment and Forestry Minister Siti Nurbaya Bakar, this still-to-be-named calf is the fifth born under a semi-wild breeding program at the park. The new addition brings the rhino herd at Way Kambas up to 10 animals and follows the birth of another calf in September. 

[Related: Rhinos pay a painful price for oxpecker protection.]

The sanctuary is part of a special zone in the national park where all of the rhinos are protected and looked after by local experts.

“The main objective is to produce Sumatran rhino calves to maintain the survival of the Sumatran rhino species which is now threatened with extinction,” sanctuary Director General of Natural Resources and Ecosystem Conservation Satyawan Pudyatmoko said in a statement. “The Sumatran rhino calves are the result of a breeding program. In the future, at SRS TNWK they can be released back into their natural habitat.”

Veterinarians from the Rhino Foundation of Indonesia (Yayasan Badak Indonesia) and animal care staff will continue to closely monitor Delialah and her new calf as they bond.

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African penguins may tell each other apart by the spots in their plumage https://www.popsci.com/environment/african-penguins-spots/ Mon, 27 Nov 2023 16:00:00 +0000 https://www.popsci.com/?p=592374
Six African penguins standing on a rock. They have white plumage with black dots arranged in individual patterns on their chests.
A few members of the Zoomarine Italia penguin colony. The unique ventral dot patterns are visible on each penguin's chest. Cristina Pilenga/Animal Behaviour (2023)

The dots reemerge in the exact same position when their annual plumage comes in.

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Six African penguins standing on a rock. They have white plumage with black dots arranged in individual patterns on their chests.
A few members of the Zoomarine Italia penguin colony. The unique ventral dot patterns are visible on each penguin's chest. Cristina Pilenga/Animal Behaviour (2023)

The assortment of black dots that decorate African penguins’ mostly all-white fronts might help the birds tell each other apart. This is the first documented time that animal behaviorists and psychologists have pinpointed a physical feature that a bird species uses for visual recognition. The findings are described in a study published in the January 2024 issue of the journal Animal Behaviour.

[Related: How African penguins continue to survive changes in climate.]

In birds, distinguishing individual flock members is primarily based on auditory cues and not visual cues. For example, some parrots distinguish their offspring with squawking equivalent of individual names. This new research is one of the first studies to show that birds could use visual cues more than scientists previously believed. 

According to study co-author and animal psychologist Luigi Baciadonna, the dots on African penguins appear when they are about three to five months old. These birds molt annually and reemerge in the same position when the new plumage comes in. 

In the new study, a team from Italy’s University of Turin, the University of Oulu in Finland, and Zoomarine Italia marine park near Rome conducted a simple experiment with 12 penguins. The team built a small enclosure with plywood walls that was just tall enough to prevent a penguin from seeing over it. They placed cameras on either end of the pen and life-size pictures of two penguins on one of the far walls. One penguin entered the enclosure, where one of the pictures featured its specific mate. 

African penguins form lifelong bonds with their partners and the team tracked their responses to images of other penguins from their species. They found that the penguins spent more time looking at the picture of their partner than they did a picture of a different familiar penguin. This occurred even when the heads of the penguins were blurred. 

When the test penguins were shown two images of their partner, including one that had the spots removed, they preferred the images where the dots remained intact. However, this preference for their partner did not occur when the birds saw unspeckled versions of their mate and a different bird. According to the team, this suggests that the penguins use these spots to tell one another apart.

[Related: Jackass penguins talk like people.]

African penguins live along the coasts of Namibia and South Africa. They are about 24 to 27 inches tall and eat squid, anchovies, and other small fish. African penguins are known to be particularly communicative with one another, so scientists have studied their behavior to better understand some of the more advanced social behaviors seen in primates. A 2021 study found that African penguins are capable of vocal accommodation. Different group members have a different dialect and vocal accommodation allows group members to learn to speak more like the others. 

“Given how goofy penguins can seem–almost stumbling over their feet as they walk, for example–the birds may not seem like they are all that bright,” Baciadonna told New Scientist. “But we showed in these two or three experiments that actually they are quite complicated and complex. They’re also clever.”

Animal physiologist and director of the Institute of Neurobiology at the University of Tübingen Andreas Nieder told Science, “It is an original study with a remarkable finding.” Nieder was not involved in the new research.

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10 new species of trilobite fossil rise from volcanic ash https://www.popsci.com/environment/new-species-trilobite-fossil/ Fri, 24 Nov 2023 14:00:00 +0000 https://www.popsci.com/?p=591224
An artist's rendering of a trilobite based on preserved soft body parts. The animal has two antennae protruding from its head and is oval-shaped.
An artist's rendering of a trilobite based on preserved soft body parts. Nobu Tamura

The extinct arthropods date back at least 490 million years.

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An artist's rendering of a trilobite based on preserved soft body parts. The animal has two antennae protruding from its head and is oval-shaped.
An artist's rendering of a trilobite based on preserved soft body parts. Nobu Tamura

Geologists have discovered 10 new species of trilobite in a relatively unstudied area of Thailand. These extinct sea creatures were hidden for 490 million years and are helping scientists create a new map of the animal life during the late Cambrian period. They are described in a monograph that was published in October in the journal Papers in Palaeontology.

[Related: These ancient trilobites are forever frozen in a conga line.]

Trilobites were marine arthropods similar to today’s spiders and crustaceans and are known for a wide variety of body designs. A species called Walliserops may have jousted with ‘tridents’ on their heads to win mates and recent trilobite specimens have been found with full stomachs. More than 20,000 species lived in Earth’s seas before they went extinct about 250 million years ago.

The trilobite fossils described in the new paper were trapped between layers of petrified ash in sandstone and were the product of old volcanic eruptions. The sediment from the eruptions settled on the bottom of the sea and formed a green layer called a tuff. This important layer contains crystals of a critical mineral that formed during the eruption called zircon. Aside from being as tough as steel, zircon is chemically stable and heat and weather resistant. Zircon also persists while the minerals in other kinds of rocks erode over time. Individual atoms of uranium that transform into lead live inside these resilient zircon crystals and give paleontologists a benchmark for dating the fossils

“We can use radio isotope techniques to date when the zircon formed and thus find the age of the eruption, as well as the fossil,” study co-author and University of California, Riverside geologist Nigel Hughes said in a statement.

Finding tuffs from the late Cambrian period (between 497 and 485 million years ago) is also rather rare. According to the team, it is one of the “worst dated” intervals of time in Earth’s history.

“The tuffs will allow us to not only determine the age of the fossils we found in Thailand, but to better understand parts of the world like China, Australia, and even North America where similar fossils have been found in rocks that cannot be dated,” study co-author and Texas State University geologist Shelly Wernette said in a statement. Wernette previously worked in the Hughes Lab.

The trilobite fossils were found on the coast of an island called Ko Tarutao. This island is part of a UNESCO geopark site that has encouraged international teams of scientists to work in this area. 

One of the most interesting discoveries was 12 types of trilobites that scientists have seen in other parts of the world, but not in Thailand. 

“We can now connect Thailand to parts of Australia, a really exciting discovery,” said Wernette.

During trilobites’ lifetime, this area was located on the margins of an ancient supercontinent called Gondwanaland. The giant land mass included present day India, Africa, South America, Australia, and Antarctica. 

[Related: Ancient ‘weird shrimp from Canada’ used bizarre appendages to scarf up soft prey.]

“Because continents shift over time, part of our job has been to work out where this region of Thailand was in relation to the rest of Gondwanaland,” Hughes said. “It’s a moving, shape shifting, 3D jigsaw puzzle we’re trying to put together. This discovery will help us do that.”

They named one of the newly discovered species Tsinania sirindhornae in honor of Thai Royal Princess Maha Chakri Sirindhorn, for her dedication to developing the sciences in Thailand.

“I also thought this species had a regal quality. It has a broad headdress and clean sweeping lines,” Wernette said.

A gray fossil embedded in volcanic ash. The fossil is named Tsinania sirindhornae, a trilobite named in honor of the Thai Royal Princess and her dedication to advancing the sciences.
Fossil of Tsinania sirindhornae, a trilobite named in honor of the Thai Royal Princess and her dedication to advancing the sciences. CREDIT: Shelly Wernette/UCR.

If the team can get an accurate date from the tuffs that the remains of T. sirindhornae had been sitting in for millions of years, they could be able to determine if closely related species found in northern and southern China are roughly the same age. 

The team believes that the portrait of the ancient world hidden in these trilobite fossils contain invaluable information about our planet’s history.

“What we have here is a chronicle of evolutionary change accompanied by extinctions. The Earth has written this record for us, and we’re fortunate to have it,” Hughes said. “The more we learn from it the better prepared we are for the challenges we’re engineering on the planet for ourselves today.”

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Why these sea worms detach their butts to reproduce https://www.popsci.com/environment/deatching-butt-sea-worm/ Wed, 22 Nov 2023 14:30:00 +0000 https://www.popsci.com/?p=591162
A mature Megasyllis nipponica with a developing female stolon.
A mature Megasyllis nipponica with a developing female stolon. Nakamura et al 2023

Biologists might be closer to solving the mystery behind the Japanese green syllid worm's reproductive behavior.

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A mature Megasyllis nipponica with a developing female stolon.
A mature Megasyllis nipponica with a developing female stolon. Nakamura et al 2023

It’s been a wormy, sexual head-scratcher for years. The Japanese green syllid worm Megasyllis nipponica detaches its butt in order to reproduce. But how do these algae-eating invertebrates do this? The process could come down to some developmental genes, according to a study published November 22 in the journal Scientific Reports.

[Related: The jumping worm invasion may be less worrisome than it sounds.]

A swimming Megasyllis nipponica with a stolon in its posterior end. CREDIT: Nakamura et al 2023.

Bye bye, butt

Some segmented sea worms like the syllid worm go through a reproductive process called  stolonization. The stolon is the worm’s posterior organ and it is full of eggs or sperm depending on the worm’s sex. During stolonization, the stolon completely detaches from the rest of the worm’s body for reproduction. 

This detached butt swims around by itself and spawns when it meets another stolon of the opposite sex. This autonomous swimming is believed to protect the original body of the worm from dangers in the environment and help the eggs and sperm travel longer distances. 

In order to swim by themselves, the stolon have to develop their own eyes, antennae, and swimming bristles while still attached to their original body. How this happens has been a mystery. The formation of the stolon itself begins when the gonads near the worm’s butt mature. A head is then formed in the front of the developing stolon, with the eyes, antennae, and swimming bristles following close behind. It develops its nerves and the ability to sense and behave independently before the stolon detaches from the rest of the body.

Hot hox genes

In the new study, a team from the University of Tokyo looked into how the stolon’s head is formed in the first place. The researchers investigated the developmental gene expression patterns in worms as they were sexually maturing. A well-known group of genes that determine body part formation called hox genes help define the head regions of various animals. The team found that hox genes are expressed more in the head region of the stolon. The genes are not typically expressed as much in the middle of the body, except for when the gonads are developing. During this time, the hox genes are highly expressed in the worm’s middle and butt. 

“This shows how normal developmental processes are modified to fit the life history of animals with unique reproductive styles,” study co-author and University of Tokyo marine biologist Toru Miura said in a statement.

[Related: These newly discovered bioluminescent sea worms are named after Japanese folklore.]

Hox genes also determine the segmentation along the worm’s body. The team thought that the hox genes would be expressed differently along the invisible line that runs from the head of the worm to the back end.

“Interestingly, the expressions of Hox genes that determine body-part identity were constant during the process,” said Miura. 

Because of this consistency, the stolon does not have a separatedigestive tract. It also has repeated uniform body segments, except for in its head and tail. 

“This indicates that only the head part is induced at the posterior body part to control spawning behavior for reproduction,” said Miura.

The study showed the developmental mechanism of stolons for the first time and sparked more investigation into this reproductive method. Miura and the team hope to clarify the sex determination mechanism and the endocrine regulations during the worm’s reproductive cycles in future studies.

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These tiny worms are no match for carnivorous fungi https://www.popsci.com/science/fungus-eats-worms/ Tue, 21 Nov 2023 19:00:00 +0000 https://www.popsci.com/?p=590963
An aquatic nematode living in pond water among cyanobacteria. The small worms are sometimes trapped and eaten by carnivorous fungi.
An aquatic nematode living in pond water among cyanobacteria. The small worms are sometimes trapped and eaten by carnivorous fungi. Getty Images

Arthrobotrys oligospora sets traps for nematodes as part of a ‘constant evolutionary arms race.’

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An aquatic nematode living in pond water among cyanobacteria. The small worms are sometimes trapped and eaten by carnivorous fungi.
An aquatic nematode living in pond water among cyanobacteria. The small worms are sometimes trapped and eaten by carnivorous fungi. Getty Images

If nematodes have nightmares, they might be dreaming about the terror of being eaten alive by a carnivorous fungus called Arthrobotrys oligospora. The very real fungus can sometimes set gooey traps for these worms. It is one of over 700 known species of carnivorous fungi. New findings on the basic processes behind its unique eating habits are described in a study published November 21st in the open access journal PLoS Biology.

[Related: Parasitic Fungi Can Fuse A Nematode’s Gut Into One Cell.]

Nematodes are not usually the first thing on A. oligospora’s menu. The fungus typically gets nutrients from decaying organic matter. Starvation and the presence of nearby worms can prompt this and other fungi to create traps to capture and eat the worms. Another meat eating fungi named Pleurotus ostreatus or the oyster mushroom even uses a nerve gas as its method of trapping down nematodes. 

A. oligospora has a different approach. It generally uses sticky secretions to keep the worms pinned down before they become a meal. Earlier studies have shown some of the biological processes and genetics behind A. oligospora’s predator-prey relationship, but the molecular details of the process have remained generally unclear.

“I think it’s fascinating to consider that right under our feet in the soil, there are micro-predators like A. oligospora are continually evolving new ways to hunt, capture and consume the nematode prey and there is [a] constant evolutionary arms races between these carnivorous fungi and nematodes,” study co-author and molecular biologist Yen-Ping Hsueh tells PopSci. 

To investigate, Hsueh and a team from Academia Sinica in Taipei, Taiwan designed a series of lab experiments to pinpoint the genes and processes involved when A. oligospora preys on a nematode worm species called Caenorhabditis elegans. They used a technique called RNAseq to see the level of activity occurring in various fungus genes at different points in time. When A. oligospora first senses a worm, two separate functions increase–DNA replication and the production of ribosomes. These are the structures that build proteins in a cell. Next, activity increases on many of the genes that encode the proteins that likely help the fungus build and use its traps. These traps include secreted worm-adhesive proteins and a family of proteins the team has identified for the first time.

Traps laid by A. oligospora to catch nematodes shown glowing in green. CREDIT Hung-Che Lin
Traps laid by A. oligospora to catch nematodes shown glowing in green. CREDIT: Hung-Che Lin.

“The most surprising finding was the dramatic expansion and diversification of the DUF3129 gene family in A. oligospora compared to other fungi,” says Hsueh. “We named members of this family ‘Trap Enriched Proteins’ or TEPs, since they localize to the fungal traps and contribute to trap adhesion and nematode capture.”

After A. oligospora has extended filamentous structures called hyphae into the worm to digest it, the activity in the genes that code for a variety of enzymes called proteases also increases. A group called metalloproteases that break down other proteins is increased even more. The team believes this suggests that A. oligospora uses these proteases to aid in digestion of worms like nematodes.

[Related: Nightmare-fuel fungi exist in real life.]

This research could serve as the foundation for more research into other fungal predator-prey relationships and how A. oligospora feeds on these worms. 

“Our next steps are to further investigate the molecular function of how traps adhere to nematodes,” says Hsueh. “It’s surprising how the traps catch nematodes in such a short time, and the binding of the traps are strong enough that the nematodes almost never get a chance to escape after being trapped.”

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Scientists are confounded by the sex lives of serontine bats https://www.popsci.com/environment/serotine-bats-mating/ Mon, 20 Nov 2023 16:00:00 +0000 https://www.popsci.com/?p=590638
A serotine bat with its mouth open, showing teeth. Serotine bats are widely spread throughout Europe and Asia and have a 15 inch wingspan.
Serotine bats are widely spread throughout Europe and Asia and have a 15 inch wingspan. Alona Shulenko

The size of the bats' male genitals make penetration impossible.

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A serotine bat with its mouth open, showing teeth. Serotine bats are widely spread throughout Europe and Asia and have a 15 inch wingspan.
Serotine bats are widely spread throughout Europe and Asia and have a 15 inch wingspan. Alona Shulenko

The male sex organs of the animal kingdom come in all shapes and sizes from some that look like a bottle opener to genital stingers. For mammals, penetrative sex with a penis is needed to successfully mate. However, scientists have documented the first non-penetrative sex ever seen in a mammal. The mating technique was observed in the serotine bat (Eptesicus serotinus) and it is described in a study published November 20 in the journal Current Biology.

The mysteries of bat sex

Serotine bats are quite common in Europe and Asia, but the intricacies of bat sex remain elusive. Most previous observations of bats mating have only offered a glimpse of the backs of mating pairs. But in the new study, a team from the University of Lausanne in Switzerland and a bat rehabilitation center in Ukraine got lucky. 

[Related: How echolocation lets bats, dolphins, and even people navigate by sound.]

“By chance, we had observed that these bats have disproportionately long penises, and we were always wondering ‘how does that work?’,” study co-author and University of Lausanne evolutionary biologist Nicolas Fasel said in a statement. “We thought maybe it’s like in the dog where the penis engorges after penetration so that they are locked together, or alternatively maybe they just couldn’t put it inside, but that type of copulation hasn’t been reported in mammals until now.” 

The team placed cameras behind a grid that the bats could climb hoping to get footage of their genitals and mating from one side of the grid. They found that bats’ penises are roughly seven times longer than their partners’ vaginas. Each has a “heart-shaped” head that is also seven times wider than the common bat vaginal opening. This size and shape would make penetration after an erection impossible. The study shows that instead of functioning as a penetrative organ, the penis is more like an extra arm. It pushes the female’s tail sheath out of the way to engage in contact mating, similar to cloacal kissing in birds. Instead of penetration, the birds touch their two rear orifices called the cloaca together for only a few seconds, but long enough for sperm to be released.

The bat sex detectives

Fasel collaborated with bat enthusiast and citizen scientist Jan Jeucker, who filmed hours of footage of the serotine bat in a church attic in the Netherlands. The team analyzed 97 mating events—93 from the Dutch church and four from the Ukrainian bat rehabilitation center. During the recordings, the team did not see a single incidence of penetration. The erectile tissues of the bat penis were completely enlarged before they made any contact with the vulva. The male bats grasped their partner’s nape and moved their pelvis like a probe until it made contact with the vulva. Once contact was made, the pair remained still. These interactions lasted less than 53 minutes on average, but the longest event extended to 12.7 hours. 

After copulation, the researchers saw that the female bats had wet abdomens. They believe this dampness indicates the presence of semen, but more research is needed to confirm if sperm was actually transferred during these assumed mating events.

[Related: What bats and metal vocalists have in common.]

The team also characterized the form of serotine bat genitalia by measuring the erect penises of live bats that were captured as part of other research studies. The necropsies on bats that had died at bat rehabilitation centers revealed how much longer and wider the serotine bat penises were compared to the bat vaginas. The penises are also about a fifth as long as the bats’ head to body length. Female serotine bats also have unusually long cervixes, which potentially helps them select and store sperm.

The team believes that the bats may have evolved their oversized penises as a way to push aside the female tail membranes.  

“Bats use their tail membranes for flying and to capture the insects, and female bats also use them to cover their lower parts and protect themselves from males,” said Fasel. “But the males can then use these big penises to overcome the tail membrane and reach the vulva.”

The team plans to study bat mating behavior in more natural contexts and further investigate penis morphology and mating behavior in other bat species. 

“We are trying to develop a bat porn box, which will be like an aquarium with cameras everywhere,” says Fasel.

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Wild bonobos show surprising signs of cooperations between groups https://www.popsci.com/environment/bonobos-cooperations/ Thu, 16 Nov 2023 19:00:00 +0000 https://www.popsci.com/?p=589990
Two wild bonobos sit in a tree. Researchers examined pro-social behaviors of the smaller species of great ape in the Democratic Republic of Congo.
Researchers examined pro-social behaviors of wild bonobos in the Democratic Republic of Congo. Martin Surbeck/Harvard University

Our close primate relatives' recently observed group efforts give us a more optimistic view of human behavior.

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Two wild bonobos sit in a tree. Researchers examined pro-social behaviors of the smaller species of great ape in the Democratic Republic of Congo.
Researchers examined pro-social behaviors of wild bonobos in the Democratic Republic of Congo. Martin Surbeck/Harvard University

Cooperation between different groups of humans lies at the root of our social norms, traditions, and culture. Groups of a great ape species called bonobos may also work collaboratively with other cliques, according to a study published November 16 in the journal Science.

[Related: Bonobo ladies get to choose their mates and boy oh boy are they picky.]

Along with chimpanzees, bonobos are some of our closest living relatives. Studying their relationships can help scientists reconstruct what human traits appear to be more innate and how they evolve. However, both species of primate exhibit different levels of cooperation despite living in similar social groups that have multiple adult members of both sexes. 

Chimpanzees appear to have more hostile relationships between different groups. Even lethal aggression is not uncommon. This hostility has led researchers to assume that group conflict is an innate part of human nature. 

Bonobos might be telling a different story about how social structures and communities have evolved over time. 

“The ability to study how cooperation emerges in a species so closely related to humans challenges existing theory, or at least provides insights into the conditions that promote between-group cooperation over conflict,’ study co-author and German Primate Center evolutionary biologist Liran Samuni said in a statement.

The study looked at two groups of 31 wild adult bonobos in the Kokolopori Bonobo Reserve in the Democratic Republic of Congo over a period of two years. When the different groups of bonobos met up, they often fed, rested, and traveled together. 

“Tracking and observing multiple groups of bonobos in Kokolopori, we’re struck by the remarkable levels of tolerance between members of different groups,” Samuni said. “This tolerance paves the way for pro-social cooperative behaviors such as forming alliances and sharing food across groups, a stark contrast to what we see in chimpanzees.” 

The authors also did not observe disputes that led to the lethal aggression that has been observed in chimpanzees. The bonobos did not not interact randomly between groups. Cooperation only happened among a select few group members. 

“They preferentially interact with specific members of other groups who are more likely to return the favor, resulting in strong ties between pro-social individuals,” study co-author and Harvard University evolutionary biologist Martin Surbeck said in a statement. “Such connections are also key aspects of the cooperation seen in human societies. Bonobos show us that the ability to maintain peaceful between-group relationships while extending acts of pro-sociality and cooperation to out-group members is not uniquely human.”

[Related: Humans owe our evolutionary success to friendship.]

Cooperation between human groups leads to exchanges of ideas, knowledge, innovation, and resources. The Bonobos in the study also shared food resources across groups without any strong cultural influence. The authors believe that this challenges another existing idea that a shared culture and traits are necessary components for groups to cooperate with one another. 

The study also highlights the importance of collaboration when studying bonobos that live in remote and largely inaccessible parts of the preserve. 

“It is through strong collaborations with and the support of the local Mongandu population in Kokolopori, in whose ancestral forest the bonobos roam, that studies of this fascinating species become possible,” said Subeck, who directs research in the Kokolopori Bonobo Reserve. “Research sites like Kokolopori substantially contribute not only to our understanding of the species’ biology and our evolutionary history, but also play a vital role in the conservation of this endangered species.”

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Surprise! These sea cucumbers glow https://www.popsci.com/environment/sea-cucumbers-bioluminescent/ Wed, 15 Nov 2023 19:00:00 +0000 https://www.popsci.com/?p=589816
A bioluminescent sea cucumber called Scotoplanes or the “sea pig.”
A bioluminescent sea cucumber called Scotoplanes or the “sea pig.”. Manabu Bessho-Uehara/Nagoya University

Scientists found that 10 species of these deep-sea dwelling invertebrates are actually bioluminescent.

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A bioluminescent sea cucumber called Scotoplanes or the “sea pig.”
A bioluminescent sea cucumber called Scotoplanes or the “sea pig.”. Manabu Bessho-Uehara/Nagoya University

Like jellyfish, fungi, sea worms, and fireflies, some species of sea cucumbers glow in the dark. A team of researchers from Nagoya University in Japan have found that 10 known deep-sea species are bioluminescent in their natural habitats. The findings are part of a new textbook called The World of Sea Cucumber published on November 10.

[Related: The deepest known ocean virus lives under 29,000 feet of water.]

There are roughly 1,200 species of sea cucumbers. These marine invertebrates are found in every ocean on Earth, but they are best represented in the western Pacific and Indian Ocean. They generally live in shallow waters, but some species live at depths of thousands of feet deep. Most closely related to sea urchins, sea stars (aka starfish), sea lilies, and sand dollars, these bottom-dwellers range from as small as one inch long up to six feet. Some sea cucumbers are also known to shoot out a tangle of sticky, noodle-like goo from their butts when provoked. 

The new textbook takes readers deep underwater and discusses the bioluminescent properties of some of these sea cucumbers. According to NOAA, the light emitted by bioluminescent animals is produced by energy released from interior chemical reactions that are sometimes ejected from the organism. Its function is still a mystery, but it is generally used to ward off or evade predators, find food, or as a form of communication

The authors drew on previous sea cucumber research to highlight the differences between the shallow-dwelling and a bit more drab species and their brilliantly glowing deep-sea relatives. The book also shows the evolution of sea cucumbers from the Jurassic era roughly 180 million years ago up to the present day. 

To uncover the 10 bioluminescent sea cucumber species, the team deployed a remotely operated vehicle about 3,280 feet below the surface of Monterey Bay, California. The vehicle was equipped with a very sensitive and an arm that was robotically controlled from the ship. Unlike the more uniform bioluminescence seen in specimens taken onto ships, the light was shining from the sea cucumber’s head to tail and then back up similar to a wave.  

According to the authors, the previously unknown luminosity in these 10 deep-sea species suggests that sea cucumbers are more diverse than scientists once believed. A member of the order Molpadia is included in this discovery, which was previously believed to be a non-luminescent order of animals. 

While these sea cucumbers dwell in some of Earth’s deepest parts, they are still not immune to the effects of overfishing and particularly the drilling and mining activities that threaten their ecosystem

[Related: This headless chicken is the deep-sea ‘monster’ of our dreams.]

“As deep-sea exploration and development continue, information on their biodiversity and ecology, such as this book, becomes important as it allows us to assess the impact of human activities on deep-sea ecosystems,” textbook co-author and Nagoya University biochemist Manabu Bessho-Uehara said in a statement. “Heavy metal pollution from the mud discarded during drilling operations and motor-derived noise disrupting sound communication are important problems, but the effects on organisms when bioluminescence signals are disturbed, such as when light is obscured by drilling mud, have not been examined. It is necessary to clarify the importance of bioluminescence on the deep-sea floor and find measures that will lead to sustainable development.”

Studying the flora and fauna living in these extreme locations can also provide valuable knowledge of all life on Earth. It can help us discover new viruses that thrive in hydrothermal vents and the factors at play in Earth’s climate and carbon cycle

“I believe that understanding deep-sea ecosystems and interactions among organisms will lead to a better understanding of life on Earth itself,” said Bessho-Uehara.

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Elusive egg-laying mammal caught on camera for the first time https://www.popsci.com/environment/egg-laying-mammal-caught-on-camera/ Tue, 14 Nov 2023 14:09:27 +0000 https://www.popsci.com/?p=589531
Attenborough's long-beaked echidna, photographed by a camera trap.
Attenborough's long-beaked echidna, photographed by a camera trap. Expedition Cyclops

Rediscovered after 60 years, the funky critter is named for Sir David Attenborough and is one of only five species of monotreme remaining on Earth.

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Attenborough's long-beaked echidna, photographed by a camera trap.
Attenborough's long-beaked echidna, photographed by a camera trap. Expedition Cyclops

For the first time in over 60 years, a rare egg-laying mammal has been spotted by scientists. Attenborough’s long-beaked echidna (Zaglossus attenboroughi) was caught on camera during a major expedition in the Cyclops Mountains in Indonesia’s Papua Province.

[Related: Dams are hurting this enigmatic Australian species.]

A sacred animal

The long-beaked echidna is named for wildlife documentarian and conservationist Sir David Attenborough and has only been recorded by scientists once in 1961. It is considered a monotreme, or an evolutionary distinct group of mammals who can lay eggs. The platypus is also a monotreme and there are only five remaining species of these strange types of mammal on Earth. 

They live in burrows and mainly eat insects, earthworms, and termites. They are listed as Critically Endangered on the IUCN Red List of Threatened Species and are only known to live in the Cyclops Mountains.

“Attenborough’s long-beaked echidna has the spines of a hedgehog, the snout of an anteater, and the feet of a mole. Because of its hybrid appearance, it shares its name with a creature of Greek mythology that is half human, half serpent,” University of Oxford biologist James Kempton said in a statement. “The reason it appears so unlike other mammals is because it is a member of the monotremes–an egg-laying group that separated from the rest of the mammal tree-of-life about 200 million years ago.”

The echidna also has cultural significance for the people in the village of Yongsu Sapari. They have lived on the northern slopes of the Cyclops Mountains for eighteen generations. Rather than fighting during conflicts, the tradition is for one party to go up into the Cyclops to find echidna while the other party goes to the ocean to search for a marlin. Both of these creatures were difficult to find and it would take decades to even whole generations to locate them. However, once they were found, the marlin and echidna would symbolize the end of the conflict.

Finding echidnas, whip scorpions, and forest shrimp

During an expedition that began in 2019, a group of scientists from institutions in multiple countries set up over 80 trail cameras. They did not see any signs of the echidna for four weeks of trekking through a “beautiful but dangerous land.” A sudden earthquake forced the team to evacuate, one team member broke his arm in two places, another contracted malaria, and another had a leech attached to his eye for a day and a half.

[Related: Meet the first electric blue tarantula known to science.]

On the last day of the expedition, they finally spotted Attenborough’s long-beaked echidna. The identification of the species was later confirmed by mammalogist Kristofer Helgen from the Australian Museum Research Institute.

In addition to this elusive egg-laying mammal, this expedition marked the first comprehensive assessment of mammal, reptile, amphibian, and invertebrate life in the Cyclops Mountains. They combined Western scientific techniques with the extensive local knowledge of Papuan team members. Among the new discoveries are several insect species that are completely new to science and an entirely new genus of ground and tree-dwelling shrimp.

“We were quite shocked to discover this shrimp in the heart of the forest, because it is a remarkable departure from the typical seaside habitat for these animals,” entomologist  Leonidas-Romanos Davranoglou from the Oxford University Museum of Natural History said in a statement. “We believe that the high level of rainfall in the Cyclops Mountains means the humidity is great enough for these creatures to live entirely on land.”

Some other funky underground species including blind spiders, blind harvestman, and a whip scorpion were also found living in a previously unexplored cave system. The team hope that its rediscovery of Attenborough’s long-beaked echidna and all of these new species will help bring attention to the conservation needs of the Cyclops Mountains and Indonesian New Guinea.

CORRECTION November 19, 2023 3:55 PM EST: An earlier version of the article summary said the animal was named after Richard Attenborough. Zaglossus attenboroughi is named for Sir David Attenborough. We regret the error.

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These newfound beetles have male genitals shaped like a bottle opener https://www.popsci.com/environment/new-beetle-weird-genetalia/ Mon, 13 Nov 2023 14:30:00 +0000 https://www.popsci.com/?p=589420
A lateral view of Loncovilius carlsbergi. It is a six-limbed beetle less than an inch long, with two antennae protruding from its head.
Loncovilius carlsbergi is among six newly-named species found at the Natural History Museum of Denmark.

Loncovilius carlsbergi is found living on flowers in South America and not on the floor of a bar.

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A lateral view of Loncovilius carlsbergi. It is a six-limbed beetle less than an inch long, with two antennae protruding from its head.
Loncovilius carlsbergi is among six newly-named species found at the Natural History Museum of Denmark.

Researchers in Denmark have discovered six new species of beetle, including one with some eye-opening genitalia. Loncovilius carlsbergi has a penis shaped like a bottle opener. The top looks like the protruding longer part of a bottle opener that latches onto the bottle cap, and the bottom resembles the pincer that holds the bottle in place. The specimen is described in a study published October 28 in the Zoological Journal of the Linnean Society.

[Related: Acrobatic beetle bots could inspire the latest ‘leap’ in agriculture.]

While the team from the Natural History Museum of Denmark still not sure why Loncovilius carlsbergi evolved this uniquely shaped penis, studying them can reveal the role that the genitals play in the bugs’ daily lives. 

Drawing of the male genitalia of Loncovilius carlsbergi, which in lateral view looks like a bottle opener.
Drawing of the male genitalia of Loncovilius carlsbergi, which in lateral view looks like a bottle opener. CREDIT: José L Reyes-Hernández et al.

“Genitalia are the organs in insects that evolve to be different in every species. As such, they are often the best way to identify a species,” study co-author and biologist Aslak Kappel Hansen said in a statement. “That’s why entomologists like us are always quick to examine insect genitalia when describing a species. The unique shape of each species’ genitals ensures that it can only reproduce with the same species.”

Aslak and his colleagues found and named six new species in the rove beetle genus Loncovilius that had been hidden within the insect collections at the museum. Loncovilius carlsbergi was named for the Carlsberg Foundation, which has funded research at the museum for years. Carlsberg is a popular 176-year-old Danish beer company.

Loncovilius beetles are only found in Chile and Argentina and entomologists don’t know too much about them. They are less than an inch long and all of their legs have sticky bristles on them, while other predatory rove beetles only have sticky front legs. 

Where Loncovilius beetles live make them special among this family of beetles. Most predatory rove beetles live on the ground, among dead leaves, fungi, and bark. Loncovilius beetles live on flowers. The authors believe that their sticky legs helped them adapt the ability to climb flowers and vegetation.

“We suspect that they play an important role in the ecosystem. So, it’s worrying that nearly nothing is known about this type of beetles, especially when they’re so easy to spot–and some of them are even quite beautiful,” study co-author and systematic entomologist Josh Jenkins Shaw said in a statement. “Unfortunately, we can easily lose species like these before they’re ever discovered.”

The forces of climate change, pollution, and habitat loss is exacerbating the Earth’s biodiversity crisis. These combined forces have threatened over one million plant and animal species with extinction, a rate of loss that is 1,000 times greater than previously expected. The team believes that this crisis will likely affect these newly discovered beetles as well.

[Related: A pocketful of bacteria helps these beetles through their most dramatic life changes.]

Loncovilius populations are likely to change in coming decades. Our simulations demonstrate that at least three of the Loncovilius species are at risk because the rapidly changing climate strongly alters more than half of their habitat area by 2060,” study co-author and PhD student José L. Reyes-Hernández said in a statement. “It is important to stress that many more species will be affected by this change, but we don’t know how because only for four species we had enough data for our analysis.” 

The planet’s species are also going extinct faster than scientists can fully name and describe them. Some estimates place the number of species lost from the Earth every day at upwards of 150. According to Jenkins Shaw, as many as 85 percent of all species on the planet are still not formally named or described. 

“A taxonomic name is important because nature conservation relies on knowledge about species in particular areas. Without such a description, species are often left out of conservation efforts,” said Jenkins Shaw.

The authors hope that Loncovilius carlsbergi’s attention-grabbing genitals could spark broader interest in insects. They are also working on producing an actual bottle opener shaped like this beetle’s penis into production. 

“It’s important that we recognize the vast wealth of yet to be researched species around us before it’s too late. We would like for people around the world to talk about the crisis facing our planet’s species. A move towards serious learning and awareness may be sparkled by a light chat that takes place over a beer,” said Kappel Hansen.

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Beyond the mitochrondrion: How did our cells get their other complex parts? https://www.popsci.com/science/cell-structure-how/ Fri, 10 Nov 2023 23:00:00 +0000 https://www.popsci.com/?p=588561
Unlike bacteria, eukaryotic cells contain membrane-bound structures that compartmentalize the cell into separate spaces that carry out different jobs. How this architecture evolved is hotly debated.
Unlike bacteria, eukaryotic cells contain membrane-bound structures that compartmentalize the cell into separate spaces that carry out different jobs. How this architecture evolved is hotly debated. Getty

There's more to the cell than its 'powerhouse.'

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Unlike bacteria, eukaryotic cells contain membrane-bound structures that compartmentalize the cell into separate spaces that carry out different jobs. How this architecture evolved is hotly debated.
Unlike bacteria, eukaryotic cells contain membrane-bound structures that compartmentalize the cell into separate spaces that carry out different jobs. How this architecture evolved is hotly debated. Getty

This article was originally featured on Knowable Magazine.

More than 1.5 billion years ago, a momentous thing happened: Two small, primitive cells became one. Perhaps more than any event—barring the origin of life itself—this merger radically changed the course of evolution on our planet.

One cell ended up inside the other and evolved into a structure that schoolkids learn to refer to as the “powerhouse of the cell”: the mitochondrion. This new structure provided a tremendous energetic advantage to its host—a precondition for the later evolution of complex, multicellular life.

But that’s only part of the story. The mitochondrion is not the only important structure within complex, eukaryotic cells. There’s the membrane-bound nucleus, safekeeper of the genome. There’s a whole system of internal membranes: the endoplasmic reticulum, the Golgi apparatus, lysosomes, peroxisomes and vacuoles—essential for making, transporting and recycling proteins and other cargo in and around the cell.

Where did all these structures come from? With events lost in the deep past and few traces to serve as evolutionary clues, it’s a very tough question to tackle. Researchers have proposed various hypotheses, but it is only recently, with some new tools and techniques, that cell biologists have been able to investigate the beginnings of this intricate architecture and shed some light on its possible origins.

A microbial merger

The idea that eukaryotes originated from two cells merging dates back more than 100 years but did not become accepted or well known until the 1960s, when the late evolutionary biologist Lynn Margulis articulated her theory of endosymbiosis. The mitochondrion, Margulis said, likely originated from a class of microbes known as alphaproteobacteria, a diverse group that today includes the bacterium responsible for typhus and another one important for the genetic engineering of plants, among many others.

Nothing was known about the nature of the original host cell. Scientists proposed that it already was fairly complicated, with a variety of membrane structures inside it. Such a cell would have been capable of engulfing and ingesting things—a complicated and energetically expensive eukaryotic feature called phagocytosis. That might be how the mitochondrion first got into the host.

But this idea, called the “mitochondria late” hypothesis, doesn’t explain how or why the host cell had become complex to begin with.

In 2016, evolutionary biologist Bill Martin, cell biologist Sven Gould and bioinformatician Sriram Garg, at the University of Dusseldorf in Germany, proposed a very different model known as the “mitochondria early” hypothesis. They argued that since no primitive cells today have any internal membrane structures, it seems very unlikely that a cell would have had these over 1.5 billion years ago.

Instead, the scientists reasoned, the endomembrane system—the whole hodgepodge of parts found inside complex cells today—could have evolved soon after the alphaproteobacterium took up residence inside a relatively simple host cell, of a kind from a class called archaea. The membrane structures would have arisen from bubbles, or vesicles, released by the mitochondrial ancestor.

Free-living bacteria shed vesicles all the time, for all sorts of reasons, Gould, Garg and Martin note, so it seems reasonable to think they’d continue to do that when enclosed inside a host.

Eventually, these vesicles would have become specialized for the functions that membrane structures perform today inside eukaryotic cells. They would even fuse with the host cell’s membrane, helping to explain why the eukaryote plasma membrane contains lipids with bacterial features.

Biology photo

Vesicles could have served an important initial function, says biochemist Dave Speijer of the University of Amsterdam. The new endosymbiont would have generated plenty of poisonous chemicals called reactive oxygen species, by oxidizing fatty acids and burning them for energy. “These destroy everything, they are toxic, especially on the inside of a cell,” Speijer says. Sequestering them inside vesicles would have helped keep the cell safe from harm, he says.

Another problem created by the new guest could also have been helped by making membranes barriers, Gould, Garg and Martin add. After the alphaproteobacterium arrived, bits of its DNA would have mixed with the genome of the archaeal host, interrupting important genes. Fixing this would mean evolving machinery to splice out these foreign pieces—today they’re known as introns—from the messenger RNA copies of genes, so those protein-making instructions wouldn’t be garbled.

But that created yet another problem. The protein-making machinery—the ribosome—works extremely fast, joining several amino acids together per second. In contrast, the intron-removing system of the cell is slow, snipping out about one intron per minute. So unless the cell could keep the mRNA away from ribosomes until the mRNA was properly processed, the cell would produce many nonsensical, useless proteins.

The membrane surrounding the nucleus provided an answer. Serving as a spatial barrier, it allows mRNA splicing to finish up in the nucleus before the intron-free mRNA is translated in the cell’s internal fluid, the cytosol. “This is the selective pressure behind the origin of the nucleus,” Martin says. To form it, vesicles secreted by the endosymbiont would have flattened and wrapped around the genome, creating a barrier to keep ribosomes out but still allowing small molecules to pass freely.

An inside-out explanation

In short, Gould, Garg and Martin’s hypothesis explains why endomembrane compartments evolved: to solve problems created by the new guest. But it doesn’t fully explain how the alphaproteobacterium got inside the host to begin with, says cell biologist Gautam Dey at EMBL in Heidelberg, Germany; it assumes the endosymbiont is already inside. “This is a massive problem,” Dey says.

An alternative idea, proposed in 2014 by cell biologist Buzz Baum of University College London (with whom Dey once worked) and his cousin, University of Wisconsin evolutionary biologist David Baum, is the “inside-out” model. In this scenario, the alphaproteobacterium and the archaeal cell destined to be its eventual host would have lived side by side for millions of years in an intimate symbiosis, each depending on the other’s metabolic products.

The archaeal cell would have had long protrusions, as seen on some modern-day archaea that live in close association with other microbes. The alphaproteobacterium would have nestled up against these slender extensions.

Eventually, the protrusions would have wrapped around the alphaproteobacterium and enclosed it completely. But during the long stretch of time before that happened, the archaeal cell would have begun some spatial division of labor: It would keep information-processing jobs in its center, where the genome was, while functions like protein building would take place in the cytosol within the protrusions.

Biology photo

The power of the inside-out model, Buzz Baum says, is that it gives the cell eons of time, before the alphaproteobacterium becomes fully enclosed, to evolve ways to regulate the number and size of the mitochondrion and other membrane compartments that would eventually become fully internal. “Until you can regulate them, you’re dead,” Buzz Baum says.

The model also explains why the nucleus has the shape that it does; in particular, it provides an explanation for its unusually large pores. Viewed from inside the center of an archaeal cell, the long protrusions would be openings that could naturally become big pores like those, Baum says.

Most important, the inside-out model explains how the alphaproteobacterium would have gotten inside the archaeal host in the first place.

Still, the inside-out model has features it needs to explain. For example, the mitochondrion would end up in the wrong place—inside the endoplasmic reticulum, the network of tubes on which sit the cell’s protein-making ribosomes, as the archaeal protrusions wrapped around it. And so an additional step would be required to get the alphaproteobacterium into the cytoplasm.

But Martin’s main objection is that the inside-out model does not provide an evolutionary pressure that would have caused the nucleus or other membrane-bound compartments to arise in the first place. The inside-out model “is upside-down and backwards,” Martin says.

The nucleus: A riddle in the middle

Though the models agree that the mitochondrion evolved from an alphaproteobacterium, they have very different ideas about the origin of the nucleus and other organelles.

In the Gould, Garg and Martin model, the source for all of the structures would have been vesicles released by the evolving mitochondrion. Vesicles to contain reactive chemicals or cellular cargo, and the ability to move this cargo around, would have evolved very early. The nucleus would have come later.

In the inside-out model, the nucleus was, essentially, the remains of the archaeal cell after it wrapped its membranes around the alphaproteobacterium. So it would have appeared immediately. The endoplasmic reticulum also would have formed early, created from those squished-together protrusions. Other organelles would have come later—arising, Buzz Baum says, from buds of archaeal membrane.

Thus the models also make different predictions about the chemical nature of the membranes of cell organelles—at least originally—and how today’s complex cells came to have membrane lipids that are all chemically like the ones in bacteria, not archaea.

In the Gould, Garg and Martin model, in the beginning all the membranes except for the host cell’s outermost one would have been bacterial, like the membranes of the new resident. Then, as bacterial vesicles fused with this archaeal outer membrane, the bacterial lipids would slowly replace the archaeal ones.

In the inside-out model, the membranes of the nucleus and endoplasmic reticulum — and probably others — would have been archaeal, like the host, to start. Only later on, after genes from the bacterial genome moved over to the archaeal genome, would the lipids become bacterial in nature, Baum suggests.

How to test these ideas? Through experiments, cell biologists are starting to glimpse ways in which simple vesicles could have diversified into different organelles with distinct jobs—by taking on different shapes, like the layered membrane stacks of the modern endoplasmic reticulum or the Golgi body, or by ending up with different proteins inside them or on their membranes.

They are also highlighting the dynamism of the modern-day mitochondrion—and its potential to spawn new membrane structures.

Take, for example, the compartment that Speijer thinks evolved early in order to deal with reactive oxygen species: the peroxisome.

In 2017, cell biologist Heidi McBride of McGill University in Montreal reported that cells lacking peroxisomes could generate them from scratch. Working with mutant human fibroblast cells without peroxisomes, her team found that these cells put proteins that are essential for peroxisome function into mitochondria instead. Then the mitochondrial membrane released them as little bubbles, or vesicles.

These vesicles, or proto-peroxisomes, matured into true peroxisomes when they fused with another type of vesicle derived from endoplasmic reticulum, which carry a third necessary peroxisome protein. “It’s a hybrid organelle,” McBride says.

For McBride, this is an indication that peroxisomes—and probably other organelles—originally came from mitochondria (not exclusively from the endoplasmic reticulum, as previously believed). “The presence of mitochondria launched the biogenesis of new organelles,” she says. “In the case of peroxisomes, it’s quite direct.”

Other mitochondrion antics have also been noted.

First, a 2021 report from the lab of biochemist Adam Hughes at the University of Utah found that when yeast cells are fed toxic amounts of amino acids, their mitochondria will shed vesicles that are loaded with transporter molecules. The transporters move amino acids into the vesicles, where they won’t poison the mitochondria.

Hughes also discovered that the vesicles shed by the mitochondria can form long, tubule-like extensions with multiple layers, reminiscent of the layered stacks of the endoplasmic reticulum and the Golgi body. The structures persist in the cell for a long time. “They’re definitely their own unique structure,” Hughes says.

And in 2022, immunologist Lena Pernas, now at UCLA, showed that multilayered, mitochondria-derived structures can form in other contexts, too. When a cell is infected by the parasite Toxoplasma, her team found, the mitochondria surround the parasite and change shape. The parasite responds, and the upshot is that the mitochondrion ends up shedding large bits of outer membrane.

This microscopic image shows what happens when the parasite Toxoplasma gondii (in red) infects a mouse cell. The cell’s mitochondria (in green) gather around the invader and begin to shed vesicles (green bubbles) made of mitochondrial outer membrane. Sometimes, the vesicles can form elaborate, multilayered structures. Observations like this suggest a way in which the various endomembrane structures could have evolved early on during the evolution of eukaryotes. CREDIT: LENA PERNAS
This microscopic image shows what happens when the parasite Toxoplasma gondii (in red) infects a mouse cell. The cell’s mitochondria (in green) gather around the invader and begin to shed vesicles (green bubbles) made of mitochondrial outer membrane. Sometimes, the vesicles can form elaborate, multilayered structures. Observations like this suggest a way in which the various endomembrane structures could have evolved early on during the evolution of eukaryotes. CREDIT: LENA PERNAS LENA PERNAS

Pernas, who wrote about mitochondrial remodeling in the Annual Review of Physiology in 2016, recently discovered that these structures, which initially look like simple vesicles, also can grow and take on more complex shapes, such as stacks of sheet-like layers. What’s more, the stress of infection changes what sorts of proteins are placed on these shed bits of mitochondrial membrane. Such changes open the door for the stacked sheets to behave in different ways than they normally would, presenting the opportunity to take on new jobs, Pernas says.

The more Pernas and Hughes study these structures—found in quite different cells and conditions—the more similar they look. It’s tantalizing, says Hughes, to imagine how a structure like this, forming in the early days of eukaryote evolution, could have evolved over eons of natural selection into some of the endomembrane compartments existing in cells today.

It may never be possible to know for sure what happened such a very long time ago. But by exploring what can happen in today’s living bacterial, archaeal and eukaryotic cells, scientists can get more clarity on what was possible—and even probable. A cell moves into another cell, bringing benefits but also problems, setting off a complex cascade. And then, McBride says, “all this stuff blooms and blossoms.”

This article originally appeared in Knowable Magazine, an independent journalistic endeavor from Annual Reviews. Sign up for the newsletter.

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Hummingbirds have two creative strategies for flying through tight spaces https://www.popsci.com/environment/how-hummingbirds-fly-through-tight-spaces/ Fri, 10 Nov 2023 13:00:00 +0000 https://www.popsci.com/?p=588344
An Anna’s hummingbird with bright pink plumage flies near some leafy green trees.
Anna’s hummingbirds (Calypte anna) are the most common hummingbirds on the West Coast of the United States and have a wingspan that’s only 4.7 inches wide. Deposit Photos

The sideways vs. the bullet.

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An Anna’s hummingbird with bright pink plumage flies near some leafy green trees.
Anna’s hummingbirds (Calypte anna) are the most common hummingbirds on the West Coast of the United States and have a wingspan that’s only 4.7 inches wide. Deposit Photos

Hummingbirds are some of the world’s fastest birds and must frequently squeeze through tiny spaces in plants to get to the nectar that they need to keep up their energy. However, over time, they have lost their ability to fold their wings close to their bodies at the wrist and elbow like other birds. How hummingbirds squeeze into such tight spaces has remained a mystery to ornithologists until now. A study published November 9 in the Journal of Experimental Biology found that they deploy two very specific strategies: the sideways and the bullet.

[Related: This hybrid hummingbird’s colorful feathers are a genetic puzzle.]

Into the flight arena

The study focused on Anna’s hummingbirds (Calypte anna). These are among the most common hummingbirds living along the West Coast of the United States. They are about the size of a ping-pong ball and have iridescent emerald feathers and sparkling pink throat plumage. 

A team from the University of California, Berkeley designed a two-sided flight arena for the experiment. They used alternating rewards to train the hummingbird to fly through a 2.48 square inch gap in the partition that separated the two sides of the arena. To do so, they only refilled a feeder shaped like a flower with a sip of sugar water if the bird returned to the feeder that was on the other side through one of the gaps. This encouraged the birds with an only 4.7 inch-wide wingspan to flit around the arena. 

The team then replaced the gap between the two sides of the flight arena with a series of smaller oval and circular openings that ranged from 4.7 inches to only 2.3 inches in height, width, and diameter. The birds’ movements were recorded using high-speed cameras, to get a sense of how they negotiated the various openings. 

Next, the team wrote a computer program to methodically track the position of each bird’s bill as it approached and passed through each hole. The program also pinpointed where the hummingbird’s wing tips were, to calculate their wing positions as they transited through.

[Related: These female hummingbirds don flashy male feathers to avoid unwanted harassment.]

The experiment revealed that the hummingbirds used two unique strategies to negotiate the gaps. 

The sideways

CREDIT: Marc Badger

In the first strategy, the hummingbirds approached the circular opening and usually hovered in front of it to assess its size. They then traveled through it sideways, reaching forward with one wing and sweeping the second wing back, similar to the shape of a cross. Their wings were still fluttering to fly through the door and then swiveled forward to continue on their way. 

The bullet

CREDIT: Marc Badger

For the second strategy, the birds swept their wings backwards, pinning them to their bodies. They then quickly shot through the opening beak first like a bullet, before sweeping their wings forward. They resumed flapping their wings once they were safely through the circle. All of the hummingbirds in the study generally deployed this technique as they grew bolder and more familiar with the arena.

Changing tactics

The team observed that the hummingbirds who used the first strategy of sideways traveling tended to fly more cautiously than those that shot through the circles beak first. As the birds became more familiar with the openings after multiple approaches, they appeared to become more confident. They started to approach them quicker and dropped the more sideways way of getting through in favor of shooting through beak first. 

For the smallest opening–only half a wingspan wide–every bird zipped through facing forward with their wings back. Even the more cautious birds did this on their first attempt to avoid collisions. 

According to the team, about eight percent of the birds in the experiment clipped their wings as they passed through the partition and only one experienced a major collision. The bird who did experience the collision was able to successfully reattempting the move and continue flying.  

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Virus observed sucking on another virus’ ‘neck’ for the first time https://www.popsci.com/science/virus-attached-to-another-virus/ Thu, 09 Nov 2023 15:00:00 +0000 https://www.popsci.com/?p=588312
A colorized image of the newly discovered satellite virus latched onto its helper virus. The helper virus is larger and shown in a dark blue, while the satellite virus is smaller and purple. It is attached at the "neck" of the helper virus.
A colorized image of the newly discovered satellite virus latched onto its helper virus. This research represents the first time scientists have observed one virus attached to another. Tagide deCarvalho

This Mini-Flayer and Mind-Flayer virus are in a serious long-term relationship.

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A colorized image of the newly discovered satellite virus latched onto its helper virus. The helper virus is larger and shown in a dark blue, while the satellite virus is smaller and purple. It is attached at the "neck" of the helper virus.
A colorized image of the newly discovered satellite virus latched onto its helper virus. This research represents the first time scientists have observed one virus attached to another. Tagide deCarvalho

For the first time, scientists have observed one virus attaching itself to another virus. An electron microscope captured the interaction in stunning detail and shows how these two different viruses may have co-evolved. The findings were published in the Journal of the International Society of Microbial Ecology on October 31. 

[Related: The deepest known ocean virus lives under 29,000 feet of water.]

The viruses in the study are both categorized as bacteriophages. These are a group of viruses that are known to infect bacteria. Bacteriophages also infect single-celled prokaryotic organisms known as archaea and are commonly called “phages.” 

A colorized image of the newly discovered satellite virus latched onto its helper virus. The helper virus is larger and shown in a dark blue, while the satellite virus is smaller and purple. It is attached at the "neck" of the helper virus.
A colorized image of the newly discovered satellite virus (shown in purple) latched onto its helper virus. This research represents the first time scientists have observed one virus attached to another. CREDIT: Tagide deCarvalho

Some viruses called satellites (shown in purple) depend on both their host organism and another virus known as a helper to complete its life cycle. The satellite virus depends on the helper virus to build the protective shell that covers its genetic material called a capsid or to help it replicate its DNA.  For this relationship to continue, the satellite and the helper must be close to one another for at least a little while, but there were no known cases of a satellite virus attaching to the helper until this discovery. 

“When I saw it, I was like, ‘I can’t believe this,’” study co-author and University of Maryland, Baltimore County biologist Tagide deCarvalho said in a statement. “No one has ever seen a bacteriophage—or any other virus—attach to another virus.”

The students who isolated the satellite nicknamed it the MiniFlayer and dubbed its helper the MindFlayer. The team saw this viral relationship between the satellite MiniFlayer and helper MindFlayer while looking at some samples of a family of bacteriophage satellites that infect Streptomyces bacteria. They initially believed that the samples had been contaminated due to the large sequences of DNA and some smaller sequences of DNA that didn’t match anything they were familiar with. 

They took detailed electron microscopy images that show 80 percent of helper viruses in this sample had a satellite bound at its “neck,” where the helper’s outer shell connects to its tail. The ones that did not still had remnant satellite tendrils at the neck that the team said looked like “bite marks.”

Next, they analyzed the genomes of the bacteriophages and bacterial hosts. The satellite viruses had genes that coded for their outer protein shell, but did not have the genes needed to multiply within bacterial cells. This evidence supported the idea that both types of bacteriophages were actually interacting with each other. 

[Related: Ask Us Anything: Can viruses be good for us?]

They also saw that the satellite viruses did not have a gene that is necessary for them to integrate into the genome of bacterial host cells after they have entered them. Since most of the satellite viruses can hide in the host’s DNA, they can replicate once the right helper comes along. According to the team, the satellite thus attaches to the helper using a unique adaptation at its tail, so that it can survive without this key gene.

 “Attaching now made total sense, because otherwise, how are you going to guarantee that you are going to enter into the cell at the same time? This satellite has been tuning in and optimizing its genome to be associated with the helper for, I would say, at least 100 million years,” co-author and  University of Maryland, Baltimore County computational biologist Ivan Erill said in a statement

As of now, this kind of relationship has only been observed in a laboratory setting. Understanding these long-term viral relationships could help scientists discover numerous other examples in nature. 

“It’s possible that a lot of the bacteriophages that people thought were contaminated were actually these satellite-helper systems,” said deCarvalho. “So now, with this paper, people might be able to recognize more of these systems.”

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The mystery of why some dinosaurs got so enormous https://www.popsci.com/science/why-were-dinosaurs-so-big/ Thu, 09 Nov 2023 14:00:00 +0000 https://www.popsci.com/?p=587024
Illustration in green, yellow, orange, and purple of big sauropod dinosaurs lifting weights in front of a prehistoric landscape
Dinosaurs didn't have to do deadlifts to gain mass. María Jesús Contreras for Popular Science

Sauropods and theropods dwarfed all other land animals. But what was the benefit of being supersized?

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Illustration in green, yellow, orange, and purple of big sauropod dinosaurs lifting weights in front of a prehistoric landscape
Dinosaurs didn't have to do deadlifts to gain mass. María Jesús Contreras for Popular Science

Dinosaur Mysteries digs into the secretive side of the “terrible lizards” and all the questions that keep paleontologists up at night.

YOU NEVER KNOW how small you are until you’re next to a big ol’ dinosaur. Find the right lighting in the museum hall and you can literally stand in the shadow of the skeletons of Apatosaurus, Patagotitan, Brachiosaurus, and other reptiles that grew far larger than any other terrestrial creature in the past 66 million years. But even after nearly two centuries of research, we have only the haziest notions of why some dinosaurs were larger than any terrestrial mammal to date.

While a number of dinosaurs fell in the supersized categoryTyrannosaurus rex weighed more than a mature male African elephant—the sauropods were the all-time titleholders. They had small heads with simple teeth, impressively long necks, hefty bodies, and tapering tails. So many sauropod species reached more than 100 feet in length, paleontologists still aren’t sure which one stretched the farthest. While the largest land mammals, like the hornless rhino Paraceratherium and the biggest fossil elephants, got to be about 18 tons, sauropods evolved to have more mass at least 36 times during their evolutionary history—an ongoing reprisal of gargantuan herbivores through the Jurassic and Cretaceous.

The stunning heft of these creatures has often led us to wonder why they got to be so much bigger than any terrestrial creature before or since. But in the realm of paleontology, “why” questions are extremely difficult to answer. Queries starting with “why” are matters of history, and in this case, the history plays out dozens of times on multiple continents over the course of more than 130 million years. Though we see the end effect, we can’t quite make out the causes.

Dinosaurs have a habit of digging their claws into our imaginations, however, so researchers have kept on, turning up a few clues in the past two decades about the surfeit of superlative sauropods. While higher oxygen levels have been linked to bigger body sizes in a few ancient insects, the atmosphere in the heyday of the dinosaurs was about the same as today’s. What’s more, the Earth’s gravitational force was just as strong in the Mesozoic era as in the modern era. So we know that the impressive size of Argentinosaurus and other top sauropods was not a matter of an abiotic factor like increased oxygen in the atmosphere or lower gravity. Our explanation lies elsewhere.

These facts only show us what allowed sauropods to become big. The dinosaurs didn’t have to drift in that direction.

Paleontologists are getting closer to the truth by looking at the dinosaurs themselves. For example, experts have identified a suite of characteristics that set sauropods apart from the mastodons and giant rhinos of the Cenozoic. Eggs have a great deal to do with it.

The largest mammals of all time were placentals, gestating their offspring on the inside so they could come out more developed. This reproductive strategy comes with some constraints. To reach even larger adult sizes, females of each species would need to carry their babies in the womb for longer. African elephants, for example, already gestate for about two years—during which much can go wrong. But sauropods, like all nonavian dinosaurs, laid multiple eggs at a time, bypassing the reproductive constraints of live birth and flooding their ecosystems with tons of babies that had the potential to grow huge (even if most ended up as snacks for the carnivores of the time). The different reproductive strategies gave dinosaurs some advantages over mammals.

Camarasaurus and other sauropods also got some assistance from their anatomical peculiarities. Sauropods had complex air-sac systems in their respiratory tracts that created air pockets within and around their bones. These nifty features kept their skeletons light without sacrificing strength, and also made extracting oxygen from the air and shedding excess body heat more efficient. The distinctive dinosaurs could grow long necks too, because they didn’t have heavy heads full of massive, grinding teeth like large herbivorous mammals over the past 66 million years. Instead, sauropods had small, light noggins full of spoon- or pencil-shaped teeth that were mostly just capable of cropping vegetation to be broken down and fermented through their gastrointestinal tracts. In other words, their guts did the work, not their teeth. Studies of ginkgoes, horsetails, and other common Mesozoic plants indicate that the ancient vegetation was more calorie-rich than previously supposed, so the abundance of green food likely fueled the reptilian giants’ unprecedented growth.

But these facts only show us what allowed sauropods to become big. The dinosaurs didn’t have to drift in that direction. In fact, some were relatively small: The island-dwelling species Magyarosaurus was about the size of a large cow. Sauropods could have thrived at smaller sizes, but they instead kept spinning off lineages of giants. We know something about what made living large possible, but what we still don’t know is what evolutionary pressures drove sauropods to evolve enormous bodies.

Predators certainly played their part. All sauropods were born small—even the largest species hatched from eggs about the size of a soccer ball. They were vulnerable to various Jurassic and Cretaceous carnivores, but growing up quickly was one way to stave off those hungry jaws. Hunting megafauna can be dangerous and even deadly, as we see with lions, wolves, and even humans today, and so sauropods may have plumped up to be less appealing to the likes of Allosaurus and T. rex.

But if carnivorous appetites were the main driver of sauropod size, we’d see a more uniform and extended “arms race” between the dinosaurs over time, resulting in gradually larger predators and prey. The fossil record instead shows that sauropods scaled up in different times and places, likely for an array of reasons ranging from local grub to what mating sauropods found sexy in each other. The repeated evolution of gigantic dinosaurs hints that there were many pathways to the sauropods’ impressive stature, not just one. Biology was as complicated back then as it is now, and we’ll never get the full story without experiencing 100-foot-long reptiles ourselves.

Read more PopSci+ stories.

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Megalodon’s warm-blooded relatives are still circling the oceans today https://www.popsci.com/environment/megalodons-warm-blooded-shark/ Wed, 08 Nov 2023 21:00:00 +0000 https://www.popsci.com/?p=587979
A side view of a great white shark. Regional endothermy in fish has been seen in apex predators like the great white sharks or giant tuna.
Regional endothermy in fish has been seen in apex predators like the great white sharks or giant tuna. Deposit Photos

Regional endothermy could help the smalltooth sand tiger shark generate power to hunt.

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A side view of a great white shark. Regional endothermy in fish has been seen in apex predators like the great white sharks or giant tuna.
Regional endothermy in fish has been seen in apex predators like the great white sharks or giant tuna. Deposit Photos

While the majority of fish are cold-blooded and rely on the temperature outside of their bodies to regulate their internal temperatures, less than one percent of sharks are actually warm-blooded. The extinct but mighty megalodon and the living great white shark generate heat with their muscles the way many mammals do. However, they are not the only sharks with this warm quirk. A study published November 7 in the journal Biology Letters found that there are more warm blooded sharks than scientists initially believed. 

[Related: Megalodons were likely warm-blooded, despite being stone-cold killers.]

Warmer muscles might help these giant carnivores be more powerful and athletic, by using that heat to generate more energy. Regional endothermy in fish has been seen in apex predators like the great white or giant tuna, but there has been debate on when this warm bloodedness evolved in sharks and if the megalodon was warm blooded. A previous study from June 2023 found that the megalodon was warm blooded and that the amount of energy it used to stay warm may have contributed to its extinction about 3.6 million years ago.

The new study looked at the results of autopsies from some unexpected shark strandings in Ireland and southern England earlier in 2023. The sharks belonged to a rarely seen species called the smalltooth sand tiger shark. These sharks are found around the world in temperate and tropical seas and in deep waters (32 to 1,700 feet deep). They have a short and pointed snout, small eyes, protruding teeth, and small dorsal and anal fins and can reach about 15 feet long. Smalltooth sand tiger sharks are considered a “vulnerable” species by the International Union for the Conservation of Nature. While they are not targeted by commercial fisheries, the sharks may be mistakenly caught in nets and may face threats from pollution. 

Smalltooth sand tiger sharks are believed to have diverged from the megalodon at least 20 million years ago. The autopsies from this year’s stranded sharks unexpectedly served as a timeline that took marine biologists from institutions in Ireland, South Africa, and the United States back millions of years. 

The team found that these rare sharks have physical features that suggest they also have regional endothermy like the megalodon, great white, and some filter-feeding basking sharks. This new addition means that there are likely more warm-blooded sharks than scientists thought and that warm bloodedness evolved quite a long time ago.

“We think this is an important finding, because if sand tiger sharks have regional endothermy then it’s likely there are several other sharks out there that are also warm-bodied,” study co-author and marine biologist Nicholas Payne said in a statement. “We used to think regional endothermy was confined to apex predators like the great white and extinct megalodon, but now we have evidence that deep water ‘bottom dwelling’ sand tigers, and plankton-eating basking sharks also are warm bodied. This raises plenty of new questions as to why regional endothermy evolved, but it might also have important conservation implications.” Payne is affiliated with Trinity College in Dublin, Ireland. 

[Related: Were dinosaurs warm-blooded or cold-blooded? Maybe both.]

Scientists believe that the megalodon’s warmer body allowed it to move faster, tolerate colder water, and spread all over the world’ oceans. However, this evolutionary advantage could have contributed to its downfall. The megalodon lived during the Pliocene Epoch (5.33 million years to 2.58 million years ago) when the world cooled and sea levels changed. These ecosystem changes and competition with newcomers in the marine environment like great whites may have led to its extinction. 

Understanding how extinct sharks met their end could help scientists gauge how today’s warm-blooded sharks could fare due to warmer ocean temperatures from human-caused climate change. It has potential conservation implications and could explain some shifting patterns of where sharks are foraging. 

“We believe changing environments in the deep past was a major contributor to the megalodon’s extinction, as we think it could no longer meet the energetic demands of being a large regional endotherm,” study co-author and Trinity College marine biologist Haley Dolton said in a statement. “We know the seas are warming at alarming rates again now and the smalltooth tiger that washed up in Ireland was the first one seen in these waters. That implies its range has shifted, potentially due to warming waters, so a few alarm bells are ringing.”   

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What head lice can tell us about human migration https://www.popsci.com/environment/head-lice-human-migration/ Wed, 08 Nov 2023 19:00:00 +0000 https://www.popsci.com/?p=587873
A louse on human hair under a microscope. Humans and lice have coevolved for thousands of years. The oldest human louse known to scientists is a 10,000 year-old specimen from Brazil.
Humans and lice have coevolved for thousands of years. The oldest human louse known to scientists is a 10,000 year-old specimen from Brazil. Getty Images

‘Lice are like living fossils we carry around on our own heads.’

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A louse on human hair under a microscope. Humans and lice have coevolved for thousands of years. The oldest human louse known to scientists is a 10,000 year-old specimen from Brazil.
Humans and lice have coevolved for thousands of years. The oldest human louse known to scientists is a 10,000 year-old specimen from Brazil. Getty Images

Reviled the world over for making our scalps itch and rapidly spreading in schools, lice have hitched their destiny to our hair follicles. They are the oldest known parasites that feed on the blood of humans, so learning more about lice can tell us quite a bit about our own species and migratory patterns. 

[Related: Ancient ivory comb shows that self-care is as old as time.]

A study published November 8 in the open-access journal PLOS ONE found that lice likely came into North America in two waves of migration. First when some humans potentially crossed a land bridge that connected Asia with present day Alaska roughly 16,000 years ago during the end of the last ice age and then again during European colonization. 

“In some ways, lice are like living fossils we carry around on our own heads,” study co-author Marina Ascunce, an evolutionary biologist with the United States Department of Agriculture, tells PopSci.  

Lice are wingless parasites that live their entire lives on their host and there are three known species that infest humans. Humans and lice have coevolved for thousands of years. The oldest louse specimen known to scientists is 10,000 years old and was found in Brazil in 2000. Since lice and humans have a very intertwined relationship, studying lice can offer clues into human migratory patterns.

“They went on this ride across the world with us. Yet, they are their own organism with some ability to move around on their own (e.g., from one head to another). It provides insight into what happened during our time together,” study co-author and mammal geneticist from the University of Florida David L. Reed tells PopSci

In this new study, a team of scientists from the United States, Mexico, and Argentina analyzed the genetic variation in 274 human lice uncovered from 25 geographic sites around the world. The analysis showed distinct clusters of lice that rarely interbreed and were found in different locations. Cluster I was found all over the world, while Cluster II was found in Europe and the Americas. The only lice that had ancestry from both clusters are found in the Americas. This distinct group of lice appears to be the result of a mixture between lice that were descended from populations that arrived with the people who crossed the Bering Land Bridge into North America and those descended from European lice. 

Researchers found genetic evidence that head lice mirrored both the movement of people into the Americas from Asia and European colonization after Christopher Columbus’s arrival in the late 1400’s.

“Central American head lice harbored the Asian background associated with the foundation of the Americas, while South American lice had marks of the European arrival,” Ariel Toloza, a study co-author and insect toxicologist at Consejo Nacional de Investigaciones Científicas y Técnica (CONICET) in Argentina, tells PopSci. “We also detected a recent human migration from Europe to the Americas after WWII.” 

[Related: Rare parasites found in 200 million-year-old reptile poop.]

The evidence in this study supports the theory that the first people living in the Americas came from Asia between 14,000 and 16,000 years ago and moved south into Central and South America. However, other archaeological evidence like the 23,000 to 21,000 year-old White Sands footprints and Native American tradition suggests that humans were already living in the Americas before and during the last ice age. Some potentially 30,000-year-old stone tools were discovered in a cave in Central Mexico in 2020, which also questions the land bridge theory. 

The study also fills in some of lice’s evolutionary gaps and the team sequenced the louse full genome for future research. 

“The same louse DNA used for this first study was used to analyze their whole genomes and also more lice were collected, so in the next year or so, there will be new studies trying to answer our ongoing questions,” says Ascunce. 

Technological improvements can also now help scientists study include ancient DNA from lice that has been found in mummies or even from louse DNA recovered from ancient combs. The study also offers some lessons in studying animals that we may generally experience as a nuisance.

“The world is full of a lot of plants and animals that are reviled or despised,” says Reed. “You never fully [know] what role they play in the environment or what their true value might be. So, be curious and see what stories the lowliest of animals might have to tell.”

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Endangered sea turtles build hundreds of nests on the Outer Banks https://www.popsci.com/environment/endangered-sea-turtles-successful-nesting-season-2023/ Mon, 06 Nov 2023 15:30:00 +0000 https://www.popsci.com/?p=586477
A baby loggerhead turtle pokes out of a shell on the sand. Its head and front flippers are out of the shell, with the lower half remaining inside.
Loggerhead turtles can weigh up to 2,000 pounds and their nests can contain as many as 100 eggs. Mark Conlin/VW PICS/UIG via Getty Image

The barrier islands saw 459 nests in 2023 including the first loggerhead turtle nest in 11 years.

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A baby loggerhead turtle pokes out of a shell on the sand. Its head and front flippers are out of the shell, with the lower half remaining inside.
Loggerhead turtles can weigh up to 2,000 pounds and their nests can contain as many as 100 eggs. Mark Conlin/VW PICS/UIG via Getty Image

North Carolina’s Outer Banks saw a busy sea turtle nesting season this year. The barrier islands stretching from Ocracoke Island north to the Virginia state saw 459 total nests between May and October, according to reporting from The Virginian-Pilot and three conservation groups in the state dedicated to sea turtle nesting.

[Related: This waddling robot could guide baby turtles to the sea.]

There are six species of sea turtles native to the United States—green, hawksbill, Kemp’s ridley, leatherback, loggerhead, and olive ridley. All six species are protected by the Endangered Species Act and four of them are known to nest in North Carolina. Human activities are the biggest threats to sea turtle species around the world. The National Oceanic and Atmospheric Administration (NOAA) says that their biggest threats are being caught in fishing gear, nesting and habitat loss, pollution and marine debris, boat strikes, climate change, and the direct harvest of sea turtles and eggs.

During the early to middle of the summer in the Outer Banks, female turtles return to the same beaches where they hatched to dig nests into the sand. They use their back flippers to dig a hole in the ground to deposit the eggs, and then cover it back up with sand. According to the National Park Service, the nesting process takes about one to three hours to complete. 

The tiny turtles hatch a few months later and follow the light of the moon to the ocean. However, their journey from their nests is quite hazardous, as they can be misdirected by artificial lights from homes and streets, crushed by human activity, or eaten by predators on their way to the ocean. 

[Related: Endangered green turtles are bouncing back in the Seychelles.]

At Cape Hatteras National Seashore, this year tied with 2022 as the second-busiest nesting season on record with 379 reported nests. The area covers more than 70 miles and stretches from Ocracoke Island north to Nags Head. The National Park Service says that the first nest was found on May 12 and the most recent was seen on October 29. The nests comprised 324 loggerhead turtles, 51 green turtles, three Kemp’s ridleys, and one leatherback. The leatherback nest was the first one seen on Hatteras National Seashore in 11 years.

Pea Island National Wildlife Refuge on the northern end of Hatteras island reported its third-busiest nesting season since 2009. The refuge covers about 13 miles and saw 43 sea turtle nests this year. By species, 37 nests belonged to loggerhead turtles and six were green turtle nests, according to data from the Sea Turtle Nest Monitoring System.

The nonprofit Network for Endangered Sea Turtles (NEST) also reported its third-busiest nesting season since 2015. Vice President Susan Silbernagel said 30 nests belong to loggerhead turtles and seven were green turtle nests. The all-volunteer organization covers about 50 miles from Nags Head up to Virginia. 

[Related: Safely share the beach with endangered sea turtles this summer.]

To better protect the endangered turtles, volunteers and scientists have been regularly monitoring the region’s beaches since 1997. Staff members and volunteers at Cape Hatteras will establish a buffer zone around the nests for added protection. 

“We could not manage and monitor sea turtle nesting without the help of over 50 dedicated volunteers that assist with monitoring of our nests and reporting and responding to sea turtle strandings,” Michelle Tongue told The Virginian-Pilot. Tongue is the deputy chief of resource management and science for the National Park Service’s Outer Banks Group. 

Sea turtles spend the vast majority of their lives in the ocean and are among the largest reptiles in the world. Kemp’s ridley and green sea turtles weigh about 75 to 100 pounds, while leatherbacks can weigh about 2,000 pounds. Sea turtles are set apart from their pond or land-dwelling relatives by their flippers. Instead of these appendages, land and pond turtles have feet with claws. 

Continued monitoring and vigilance during the 2024 nesting season will hopefully increase survival rates for these endangered reptiles.

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North America was once home to some unusual wild monkeys https://www.popsci.com/science/ekgmowechashala-fossils/ Mon, 06 Nov 2023 14:00:00 +0000 https://www.popsci.com/?p=586445
An illustration of Ekgmowechashala, the last primate to inhabit North America before humans. The animal has a white furry face, with a pink nose, and large dark eyes like a lemur. It is sitting in a leafy tree.
An illustration of Ekgmowechashala, the last primate to inhabit North America before humans. Kristen Tietjen, scientific illustrator with the KU Biodiversity Institute and Natural History Museum

According to paleontologists, the five-pound Ekgmowechashala showed up on the continent ‘like a drifting gunslinger in a Western movie.’

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An illustration of Ekgmowechashala, the last primate to inhabit North America before humans. The animal has a white furry face, with a pink nose, and large dark eyes like a lemur. It is sitting in a leafy tree.
An illustration of Ekgmowechashala, the last primate to inhabit North America before humans. Kristen Tietjen, scientific illustrator with the KU Biodiversity Institute and Natural History Museum

Humans are the only primates currently living in the wild in North America, but that was not always the case. The continent was once home to non-human primates, including big-eyed tarsier-like animals called omomyiforms and long-tailed critters called adapiforms. About 30 million years ago, a lemur-like creature named Ekgmowechashala was the last primate to inhabit the continent before Homo sapiens arrived. In a study published November 6 in the Journal of Human Evolution, fossil teeth and jaws shed some new light on this mysterious creature. 

[Related: 12-million-year-old ape skull bares its fangs in virtual reconstruction.]

From China to Nebraska

Understanding the origins of North America’s primates has been a paleontological puzzle. It’s been unclear whether they evolved on the continent or arrived from somewhere else via land bridges. The first first primates in North America date back about 56 million years at the beginning of the Eocene Epoch. Scientists believe that the primates like Ekgmowechashala generally flourished on the continent for over 20 million years. 

Ekgmowechashala was about five pounds and only one foot tall. They lived in what is now the American Plains just after the Eocene-Oligocene transition. At this time, a huge cooling and dying event made the continent much less hospitable for primates. Ekgmowechashala went extinct about 34 million years ago. 

For the study, paleontologists first had to reconstruct Ekgmowechashala’s family tree with the help of  an older “sister taxon,” or a closely related group of animals. Both groups generally share a branch on their family trees, but diverged at some point and have different lineages. This sister animal originates in and the team named it Palaeohodites, which means “ancient wanderer.” The fossils were collected by paleontologists from the United States in the 1990s from the Nadu Formation in Guangxi, an autonomous region in China. The fossils closely resembled the Ekgmowechashala material that had been found in North America in the 1960s, when the primate was still quite mysterious to North American paleontologists.

The Palaeohodites fossil potentially helps resolve the mystery of Ekgmowechashala’s strange presence in North America. It was likely a migrant to the continent instead of being the product of local evolution.

“Due to its unique morphology and its representation only by dental remains, its place on the mammalian evolutionary tree has been a subject of contention and debate. There’s been a prevailing consensus leaning towards its classification as a primate,” study co-author and University of Kansas PhD candidate Kathleen Rust said in a statement. “But the timing and appearance of this primate in the North American fossil record are quite unusual. It appears suddenly in the fossil record of the Great Plains more than 4 million years after the extinction of all other North American primates, which occurred around 34 million years ago.”

[Related: These primate ancestors were totally chill with a colder climate.]

The Ekgmowechashala fossils found in the US during the 1960s include an upper molar that looks very similar to the Palaeohodites molars found in China, according to study co-author and University of Kansas paleontologist Chris Beard. The team from Kansas closely analyzed the fossils to establish evolutionary relationships between the American Ekgmowechashala and its cousin Palaeohodites. 

The paleontologists believe that Ekgmowechashala did not descend from an older North American primate that survived the climate shift roughly 33 million years ago that caused other North American primates to go extinct. Instead, Ekgmowechashala’s ancestors likely crossed over the icy Beringian region that once connected Asia and North America millions of years later.

Rising from the dead

Ekgmowechashala is an example of the “Lazarus effect” in paleontology. This is where a species suddenly appears in the fossil record long after their relatives have died off. It is a reference to Lazarus who, according to New Testament mythology, was raised from the dead. It is also a pattern of evolution seen in the fossil record of North American primates, who went extinct about 34 million years ago. 

“Several million years later Ekgmowechashala shows up like a drifting gunslinger in a Western movie, only to be a flash in the pan as far as the long trajectory of evolution is concerned,” Beard said in a statement. “After Ekgmowechashala is gone for more than 25 million years, Clovis people come to North America, marking the third chapter of primates on this continent. Like Ekgmowechashala, humans in North America are a prime example of the Lazarus effect.”

The past is prologue?

Studying the way primates were affected by previous changes in climate can provide important insight to today’s human-driven climate change. Organisms generally retreat to more hospitable regions with the available resources or end up going extinct

“Around 34 million years ago, all of the primates in North America couldn’t adapt and survive. North America lacked the necessary conditions for survival,” said Rust. “This underscores the significance of accessible resources for our non-human primate relatives during times of drastic climatic change.

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Rats may have imaginations https://www.popsci.com/science/rats-may-have-imaginations/ Thu, 02 Nov 2023 18:00:00 +0000 https://www.popsci.com/?p=585594
A white rat pops its head out of a black box. Like in humans, the rat’s hippocampus is the part of the brain where mental maps of the world are stored.
Like in humans, the rat’s hippocampus is the part of the brain where mental maps of the world are stored. Deposit Photos

New research suggests that rats might picture where they've been and think about moving objects.

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A white rat pops its head out of a black box. Like in humans, the rat’s hippocampus is the part of the brain where mental maps of the world are stored.
Like in humans, the rat’s hippocampus is the part of the brain where mental maps of the world are stored. Deposit Photos

The ability to get lost in thoughts and use our imaginations to daydream might not be completely unique to humans. A study published November 2 in the journal Science found that rats can think about objects and places that are not right in front of them. 

[Related: How science came to rely on the humble lab rat.]

Imagining locations that are away from our current position is a component of both memory and conjuring up possible future scenarios. If animals have this ability, they could have a form of imagination that is similar to our species.

“The rat can indeed activate the representation of places in the environment without going there,” Chongxi Lai, a co-author of the study and engineer and neuroscientist at Howard Hughes Medical Institute, said in a statement. “Even if his physical body is fixed, his spatial thoughts can go to a very remote location.”

To learn more, Lai and a team at Howard Hughes Medical Institute in Maryland designed a series of experiments to see if rats can use their thoughts to imagine going towards a specific location or moving a remote object.

A new brain-machine interface and virtual reality system for rats. In this experiment, a rat uses this system to navigate to a goal solely by thinking about where it wants to go. According to the rules of this system, physical movement by the rat does not affect the rat’s location in the virtual environment. Only by controlling its hippocampal brain activity can the rat control where it goes. Specifically, in this system the animal is virtually moved toward the ‘decoded location’ that the hippocampal activity represents. CREDIT: Lai et al.

Reading a rat’s mind

When humans and rodents experience events or visit places, specific neural activity patterns are activated in their hippocampus. This area of the brain is responsible for spatial memory and stores mental maps of the rat’s world. It is also involved in recalling past events and imagining future situations. To recall memories, specific patterns related to places and events are generated in the hippocampus. Chimpanzees have been shown to have the ability to pretend, but scientists are still figuring out how chimps and other non-human animals think

To peer inside of a rat’s brain and look at these brain patterns, the team developed a real-time “thought detector.” This system measures neural activity and translates what it means using a brain-machine interface (BMI). 

The BMI produced a connection between the electrical activity occurring in the rat’s hippocampus and the animal’s position in a 360-degree virtual reality arena. It allowed the researchers to see if a rat can activate hippocampal activity to think about a location in the virtual arena without physically traveling there. 

A rat ‘thought dictionary’

With the BMI in place, the team worked to decode the brain signals in the rats. They built a “thought dictionary” of what the brain activity patterns looked like when the rat was traveling through the virtual arena in the experiment.

To do this, the rat was harnessed into a virtual reality system. As the rat walked on a spherical treadmill, its movements were translated onto a 360-degree screen. The rat was rewarded when it navigated towards its goal.

While the rat walked on the treadmill, the BMI system recorded the activity occurring in the hippocampus. The team saw which neurons were activated when the rat navigated the virtual arena to reach each goal. These signals provided them with the basis for a real-time translation of what was going on in the hippocampus.

With the thought dictionary set up, the team disconnected the treadmill. The rat was rewarded for the first step of reproducing the hippocampal activity pattern that was associated with walking towards a goal location.

The Jumper task and the Jedi task

Next, they designed two different tasks for the rats to perform–the Jumper task and the Jedi task.

In the Jumper task, the BMI translated the rat’s brain activity into motion on a screen. The animal was essentially using its thoughts to find a reward by thinking about where it needs to go to obtain it. This is a thought process similar to traveling to work or school and imagining the buildings and places we will pass along the way. 

[Related: We probably have big brains because we got lucky.]

The Jedi task had a rat hypothetically move an object to a location in its mind. The rat was fixed in a virtual place, but controlled its hippocampal activity to envision moving the object towards a goal. This is similar to how a person sitting on a couch imagining  getting up and refilling a water glass in a kitchen. The team then changed the location of the rat’s goal, which required it to produce activity patterns associated with the new location.

They found that the rats can precisely and flexibly control their hippocampal activity. Surprisingly, they could sustain this activity and hold their thoughts on a given location for many seconds. This time frame is similar to the amount of time humans can take to relive past events or imagine new scenarios.

“The stunning thing is how rats learn to think about that place, and no other place, for a very long period of time, based on our, perhaps naïve, notion of the attention span of a rat,” Tim Harris, a study co-author and biophysicist from Howard Hughes Medical Institute, said in a statement.

According to the team, this study shows how BMI can be used to probe hippocampal activity and could be a new way to study this critical region of the brain. BMI is increasingly used in prosthetics, and this new work could be used to develop devices based on these same principles.

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When a Jurassic giant died, predatory dinos probably feasted on the carcass https://www.popsci.com/science/scavenging-dinosaurs/ Wed, 01 Nov 2023 18:30:00 +0000 https://www.popsci.com/?p=585293
Photograph of the skeletal mount of an Allosaurus specimen (AMNH 5753), from William Diller Matthew's 1915 book “Dinosaurs.”
Photograph of the skeletal mount of an Allosaurus specimen (AMNH 5753), from William Diller Matthew's 1915 book “Dinosaurs.”. Project Gutenberg/Wikimedia Commons, CC0

Scavenging proved to be an evolutionary advantage in one modeling study.

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Photograph of the skeletal mount of an Allosaurus specimen (AMNH 5753), from William Diller Matthew's 1915 book “Dinosaurs.”
Photograph of the skeletal mount of an Allosaurus specimen (AMNH 5753), from William Diller Matthew's 1915 book “Dinosaurs.”. Project Gutenberg/Wikimedia Commons, CC0

Scavenging has been maligned as a food gathering strategy and is generally associated with animals like vultures and hyenas. Millions of years ago, carnivorous dinosaurs may have evolved this technique of taking meat from dead carcasses too. The findings are described in a study published November 1 in the open-access journal PLOS ONE.

[Related: Dinosaur cannibalism was real, and Colorado paleontologists have the bones to prove it.]

Carnivorous dinosaurs like the cannibalistic Allosaurus were surrounded by both living and dead prey. The bodies of large sauropod dinosaurs, some of whom could weigh more than 500,000 pounds, could have provided an important food source for carnivores.

In this study, a team of researchers from Portland State University created a simplified computer simulation of a dinosaur ecosystem from the Jurassic age. They used the animals that have been found in the 163.5 to 145 million year-old Morrison Formation in the western United States as the basis. This enormous fossil formation was once home to a wide variety of plants and dinosaurs.

The model included large carnivores common to the area like Allosaurus, large sauropods and their carcasses, and a large group of living and huntable Stegosaurus’. The carnivores were assigned traits that would improve their hunting abilities with the energy from living meat sources or their scavenging abilities with the sustenance from the carcasses. The model then measured the evolutionary fitness of the simulated predators. 

The model found that when there were a large amount of sauropod carcasses around, scavenging was more profitable than hunting for the Allosaurus. Meat eaters in these kinds of ecosystems may have evolved specialized traits to help them detect and exploit these large carcasses.

“Our evolutionary model demonstrates that large theropods such as Allosaurus could have evolved to subsist on sauropod carrion as their primary resource,” the authors wrote in a statement. “Even when huntable prey was available to them, selection pressure favored the scavengers, while the predators suffered from lower fitness.”

[Related: This 30-pound eagle would take down 400-pound prey and dig through their organs.]

This model represents only a simplified depiction of a complex ecosystem, so more variables like additional dinosaur species may alter the results. While theoretical, using models like this one can help scientists better understand how the availability of meat from carcasses can influence how predators evolve. A September 2023 modeling study found that even early humans living in southern Europe roughly 1.2 to 0.8 million years ago were scavengers. They may have competed in groups of five or more to fight off extinct giant hyenas for the carcasses of animals that had been abandoned by larger predators like saber-toothed cats.

“We think allosaurs probably waited until a bunch of sauropods died in the dry season, feasted on their carcasses, stored the fat in their tails, then waited until the next season to repeat the process,” the authors wrote. “This makes sense logically too, because a single sauropod carcass had enough calories to sustain 25 or so allosaurs for weeks or even months, and sauropods were often the most abundant dinosaurs in the environment.”

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The sea star’s whole body is a head https://www.popsci.com/science/starfish-head-body/ Wed, 01 Nov 2023 16:00:00 +0000 https://www.popsci.com/?p=585202
An orange starfish, or sea star, on a black backgorund. The unusual five-axis symmetry of sea stars has long confounded our understanding of animal evolution.
The unusual five-axis symmetry of sea stars (Patiria miniata) has long confounded our understanding of animal evolution. Laurent Formery

‘It’s not at all what scientists have assumed about these animals.’

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An orange starfish, or sea star, on a black backgorund. The unusual five-axis symmetry of sea stars has long confounded our understanding of animal evolution.
The unusual five-axis symmetry of sea stars (Patiria miniata) has long confounded our understanding of animal evolution. Laurent Formery

When looking at a sea star–or starfish–it’s not really clear which part of its identical five pointed body is considered its head. This question has puzzled biologists for decades, but some new research says that a starfish’s whole body could function like a head. The findings are described in a study published November 1 in the journal Nature and might have solved the mystery of how sea stars and other echinoderms evolved their distinctively shaped bodies.

[Related: This strange 500-million-year-old sea urchin relative lost its skeleton.]

12 starfish colored blue white white portions showing specific genes. By staining genetic material with fluorescent labels, researchers can examine how key genes behave across the sea star body.
By staining genetic material with fluorescent labels, researchers can examine how key genes behave across the sea star body. CREDIT: Laurent Formery. Laurent Formery

Searching for heads and trunks 

Sea stars are invertebrates that belong to a group of animals called echinoderms.This group also includes sea urchins and sand dollars and they all have bodies that are arranged in five equal and symmetric sections. Early in their evolution, echinoderms had a bilaterally designed ancestor with two mirrored sides more like a human’s. 

“How the different body parts of the echinoderms relate to those we see in other animal groups has been a mystery to scientists for as long as we’ve been studying them,” Jeff Thompson, a co-author of the study and evolutionary biologist at the University of Southampton in the United Kingdom, said in a statement. “In their bilateral relatives, the body is divided into a head, trunk, and tail. But just looking at a starfish, it’s impossible to see how these sections relate to the bodies of bilateral animals.”

In the new study, an international team of scientists compared the molecular markers in sea stars with a wider group of animals called deuterostomes. This group includes echinoderms like sea star and bilateral animals including vertebrates. Deuterostomes all share a common ancestor, so comparing their development can offer clues into how echinoderms evolved their more unique five-pointed body plan.

They used multiple high-tech molecular and genomic techniques to see where different genes were expressed during a sea star’s development and growth. Micro-CT scanning also allowed the team to understand the shape and structure of the animals in closer detail.

Sea star mapping

Team members from Stanford University, the University of California, Berkeley, and Pacific BioSciences, used techniques called RNA tomography and in situ hybridization to build a three-dimensional map of a sea star’s gene expression to see where specific genes are being expressed during development. They specifically mapped the expression of the genes that control the growth of a sea star’s ectoderm, which includes its nervous system and skin. 

They found gene signatures associated with head development almost everywhere in juvenile sea stars. The expression of genes that code for an animal’s torso and tail sections were also largely missing.

[Related: What’s killing sea stars?]

“When we compared the expression of genes in a starfish to other groups of animals, like vertebrates, it appeared that a crucial part of the body plan was missing,” said Thompson. “The genes that are typically involved in the patterning of the trunk of the animal weren’t expressed in the ectoderm. It seems the whole echinoderm body plan is roughly equivalent to the head in other groups of animals.”

The molecular signatures that are typically associated with the front-most portion of an animal’s head were also localized towards the middle of each of the sea star’s five arms. 

“It’s as if the sea star is completely missing a trunk, and is best described as just a head crawling along the seafloor,” study co-author and Stanford University evolutionary biologist Laurent Formery said in a statement. “It’s not at all what scientists have assumed about these animals.” 

Sea stars and other echinoderms may have evolved their five-section body plan by losing the trunk region that their bilateral ancestors once had. This chance would have allowed them to move around and feed differently than animals with two symmetrical arms.

“Our research tells us the echinoderm body plan evolved in a more complex way than previously thought and there is still much to learn about these intriguing creatures,” said Thompson. “As someone who has studied them for the last ten years, these findings have radically changed how I think about this group of animals.”

This research was supported by the Leverhulme Trust, NASA, the NSF, and the Chan Zuckerberg BioHub.

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We still don’t fully know how sunflowers turn toward the sun https://www.popsci.com/science/sunflowers-sun/ Tue, 31 Oct 2023 18:00:00 +0000 https://www.popsci.com/?p=584812
Several blooming yellow sunflowers under a blue sky with white clouds.
Sunflowers follow the sun from east to west as it moves across the sky. Deposit Photos

Their signature move appears to be different than a better known light response in plants.

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Several blooming yellow sunflowers under a blue sky with white clouds.
Sunflowers follow the sun from east to west as it moves across the sky. Deposit Photos

As Earth rotates and the sun moves across the sky from east to west, sunflowers turn their brilliant yellow faces to follow it. The mechanics behind this process, called heliotropism, is still a mystery to plant biologists. A study published October 31 in the journal PLOS Biology likely rules out that a sunflower’s ability to follow the sun is related to a more well-known response to light that all plants follow. Sunflowers probably rely on several more complicated processes to track the sun instead. 

[Related: The mathematical theory that connects swimming sperm, zebra stripes, and sunflower seeds.]

Since plants are rooted in one place, they can’t move if light they need to make food is blocked by a neighbor or if they are in a shady spot. They rely on growth or elongation to move towards the light and there are several molecular systems behind this. The best-known response is the phototropic response. Proteins called phototropins sense blue light falling unevenly on a seedling and the plant’s growth hormones are redistributed. This ultimately causes it to bend towards the light.

Plant biologists have long assumed that the sunflower’s ability to follow the sun would be based on the same mechanism as phototropism. To track the sun, the sunflower’s head leans slightly more on the eastern side of its stem. This positions their head towards the direction where the sun rises. It then shifts west as the sun moves across the sky. An earlier study showed that sunflowers have an internal circadian clock that anticipates the sunrise and coordinates the opening of its florets with the time when pollinating insects arrive in the morning. 

To investigate whether this sun-tracking ability is a shru, the team behind the new study used sunflowers grown in a laboratory and others grown outdoors in sunlight. They looked to see which genes were switched on when both sets of plants were exposed to their light sources. The indoor sunflowers grew straight towards their blue light source in the lab and activated the genes associated with phototropin. The flowers that were grown outdoors and swung their heads with the sun had a different pattern of gene expression. These sunflowers also didn’t have any apparent differences in phototropin molecules between one side of the stem and another. 

Sunflowers famously turn their faces to follow the sun as it crosses the sky. But how do sunflowers “see” the sun to follow it? New work from plant biologists at UC Davis, published October 31 in PLOS Biology, shows that they use a different, novel mechanism from that previously thought. CREDIT: Stacey Harmer/UC Davis.

“We’ve been continually surprised by what we’ve found as we study how sunflowers follow the sun each day,” study co-author and University of California, Davis plant biologist Stacey Harmer said in a statement. “In this paper, we report that they use different molecular pathways to initiate and maintain tracking movements, and that the photoreceptors best known for causing plant bending seem to play a minor role in this remarkable process.”

The team also blocked blue, ultraviolet, red, or far-red light with shade boxes. The blinders didn’t have any effect on the heliotropism response. According to the team, this indicates that there are probably multiple pathways responding to different wavelengths of light to achieve the same goal of following the sun. 

[Related: Dying plants are ‘screaming’ at you.]

The genes involved in heliotropism have not yet been identified. “We seem to have ruled out the phototropin pathway, but we did not find a clear smoking gun,” Harmer said.

When the sunflowers grown in the lab were moved outside, they began to track the sun on their first day. They initially showed a huge burst of gene expression on the shaded side of the plant that did not happen on the following days. Harmer said this suggests some kind of “rewiring” is going on in the plant.

In addition to weeding out some of the process behind how sunflowers track the sun, this work also has relevance for designing future experiments with plants to understand their mechanisms.

“Things that you define in a controlled environment like a growth chamber may not work out in the real world,” Harmer said

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Giant prehistoric lamprey likely sucked blood—and ate flesh https://www.popsci.com/environment/ancient-lamprey-blood-flesh/ Tue, 31 Oct 2023 16:00:00 +0000 https://www.popsci.com/?p=584732
An artist's illustration of an early lamprey's teeth and sucker. The Jurassic lampreys Yanliaomyzon had a feeding apparatus that surprisingly resembles that of the pouched lampreys. It foreshadows the ancestral flesh-eating habit of present day. lampreys.
The Jurassic lampreys Yanliaomyzon had a feeding apparatus that surprisingly resembles that of the pouched lampreys. It foreshadows the ancestral flesh-eating habit of present day. lampreys. Heming Zhang

A newly discovered nightmarish fossil of one of these parasitic ‘water vampires’ is 23 inches long.

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An artist's illustration of an early lamprey's teeth and sucker. The Jurassic lampreys Yanliaomyzon had a feeding apparatus that surprisingly resembles that of the pouched lampreys. It foreshadows the ancestral flesh-eating habit of present day. lampreys.
The Jurassic lampreys Yanliaomyzon had a feeding apparatus that surprisingly resembles that of the pouched lampreys. It foreshadows the ancestral flesh-eating habit of present day. lampreys. Heming Zhang

Lampreys are the vampires of the ocean and the lakes they can invade. While these eel-like parasitic vertebrates don’t use two sharp fangs to suck blood, lampreys have a toothed oral sucker that latches onto their prey and feasts on their host’s blood. Modern day lampreys are found in temperate zones of most of the world’s oceans except in Africa. However, specimens of their extinct ancient ancestors are fairly rare in the fossil record, despite dating back roughly 360 million years. Now, paleontologists in northern China have found two unusually large fossilized lamprey species that fill a large evolutionary gap. The specimens are described in a study published October 31 in the journal Nature Communications.

[Related: Why sea lampreys are going to be a bigger problem for the Great Lakes.]

“We found the largest fossil lampreys ever found in the world,” study co-author and Chinese Academy of Sciences paleontologist Feixiang Wu tells PopSci. “Based on these fossils, our study assumed that the most recent common ancestor of modern lampreys was likely eating flesh rather than sucking blood as conventionally believed.”

The earliest known lampreys date back about 360 million years ago during the Paleozoic Era. These early species are believed to have been only a few inches long and had weak feeding structures. The 160 million-year-old fossils in this new study were discovered in the Lagerstätte Yanliao Biota in northeastern China and date back to the Jurassic. The longer of the two specimens is named Yanliaomyzon occisor. It is more than 23 inches long and is estimated to have had 16 teeth. The shorter 11 inch-long species is named Yanliaomyzon ingensdentes and had about 23 teeth. By comparison, modern lampreys range from six to 40 inches long.

An artist's illustration of a lamprey from the Jurassic era. It is a long and eel-like fish with a toothed sucker on its mouth. These Jurassic lampreys from China are jawless predators of the Age of Dinosaurs. They suggest that living lampreys are ancestrally flesh-eating and most probably originated in the Southern Hemisphere of the Late Cretaceous. CREDIT: Heming Zhang
These Jurassic lampreys from China are jawless predators of the Age of Dinosaurs. They suggest that living lampreys are ancestrally flesh-eating and most probably originated in the Southern Hemisphere of the Late Cretaceous. CREDIT: Heming Zhang.

Their well-preserved oral discs and “biting” structures indicate that these lamprey species had already evolved enhanced feeding structures, bigger body size, and were predators by the Jurassic period. It also appears that they had already evolved a three-phased life cycle by this point

Lampreys begin their lives as burrowing freshwater larvae called ammocetes. During this stage, they have rudimentary eyes and feed on microorganisms with their toothless mouths. They spend several years in this stage, before transforming into adults. Some move into saltwater, while others will remain in freshwater. As adults, they become parasites that attach to a fish with their mouths and feed on their blood and tissue. Lampreys eventually return to freshwater to reproduce, where they build a nest, then spawn, and then die.

It is still unclear when lampreys evolved this lifecycle and their more complex teeth for feeding. These new well-preserved fossils fill an important gap in the fossil record and give some insights into how its lifecycle and feeding originated. 

[Related: Evolution made mosquitos into stealthy, sensitive vampires.]

The study also pinpoints where and when today’s lamprey’s first appeared. “We put modern lampreys’ origin in the Southern Hemisphere of the Late Cretaceous,” says Wu. 

The Late Cretacous lasted from 100.5 million years ago to 66 million years ago and ended with the mass extinction event that wiped out the dinosaurs. In future research, the team would like to search for specimens from the Cretaceous. According to Wu, this time period could be very important to their evolutionary history.

More fossilized specimens could also provide more accurate ideas of what kinds of flesh ancient lampreys feasted on with all those teeth and how that has evolved over time. 

“Living lampreys are always hailed as ‘water vampires,’ but their ancestor might be a flesh eater, their teeth tell,” says Wu. 

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Newfound mosasaur was like a giant Komodo dragon with flippers https://www.popsci.com/environment/mosasaur-jormungandr-walhallaensis/ Mon, 30 Oct 2023 14:30:00 +0000 https://www.popsci.com/?p=584308
An artist’s illustration of two Jormungandr walhallaensis mosasaurs fighting. The extinct creatrue is a long sea serpent with flippers, a shark-like tail, and narrow jaws. One is seen biting the other in the next, while pterosaurs fly above it.
An artist’s illustration of two Jormungandr walhallaensis mosasaurs fighting. Henry Sharpe

Jormungandr walhallaensis is named for the Norse creature Jörmungandr who will fight Thor during Ragnarok, aka the end of the world.

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An artist’s illustration of two Jormungandr walhallaensis mosasaurs fighting. The extinct creatrue is a long sea serpent with flippers, a shark-like tail, and narrow jaws. One is seen biting the other in the next, while pterosaurs fly above it.
An artist’s illustration of two Jormungandr walhallaensis mosasaurs fighting. Henry Sharpe

Paleontologists in North Dakota have discovered new species of mosasaur. These giant meat-eating aquatic lizards swam the Earth’s seas about 80 million years ago during the late Cretaceous period. This new species is named Jormungandr walhallaensis after a sea serpent in Norse mythology named Jörmungandr and Walhalla, North Dakota where its fossils were found. The findings are described in a study published October 30 in the Bulletin of the American Museum of Natural History.  

[Related: Dinosaurs who stuck together, survived together.]

“If you put flippers on a Komodo dragon and made it really big, that’s what it would have looked like,” study co-author and Richard Gilder Graduate School PhD student Amelia Zietlow, said in a statement.

The first mosasaur specimens were discovered over 200 years ago and the word “mosasaur” even predates the word “dinosaur” by roughly 20 years. There are still several unanswered questions about these ancient sea lizards, including how many times they evolved to have flippers and when they became fully aquatic. Scientists believe that they evolved to have their signature flippers at least three times and possibly four or more. It is also still a mystery if mosasaurs are more closely related to present day monitor lizards or snakes or another living creature entirely. This new specimen fills in some knowledge gaps of how the different groups of mosasaurs are related to each other.

“As these animals evolved into these giant sea monsters, they were constantly making changes,” Zietlow said. “This work gets us one step closer to understanding how all these different forms are related to one another.”

Researchers in northeastern North Dakota first discovered the Jormungandr fossil in 2015. It included a nearly complete skull, jaws, and cervical spine, and a number of vertebrae. An extensive analysis revealed that the fossil is of a new species that has multiple features that are also seen in two other mosasaurs: Clidastes and Mosasaurus. Clidastes is a smaller animal of about six to 13 feet long that lived roughly 145 million years ago. Mosasaurus was much larger at almost 50 feet long and lived about 99.6 to 66 million years ago alongside the Tyrannosaurus rex

[Related: This four-legged snake fossil was probably a skinny lizard.]

The new specimen is about 24 feet long and has flippers. It also has a shark-like tail similar to other early mosasaur species. It also likely would have had “angry eyebrows,” caused by a bony ridge on its skull. Its slightly stumpy tail would have also been shorter than the rest of its body.

Jormungandr was likely a precursor to the bigger Mosasaurus

“This fossil is coming from a geologic time in the United States that we don’t really understand,” study co-author and paleontologist from the North Dakota Geological Survey Clint Boyd said in a statement. “The more we can fill in the geographic and temporal timeline, the better we can understand these creatures.”

In Norse mythology, Jörmungandr is an enormous sea serpent or worm who encircles the Earth. Jörmungandr is believed to be the middle child of the trickster god Loki and the giantess Angrboða. Thor the god of thunder also has an ongoing battle with Jörmungandr and it is believed that the two will fight to the death during Ragnarok, or the end of the world. 

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Why ladybugs and ‘Halloween beetles’ are everywhere right now https://www.popsci.com/environment/why-are-there-are-so-many-ladybugs/ Fri, 27 Oct 2023 12:00:00 +0000 https://www.popsci.com/?p=583872
The Asian Lady Beetle (Harmonia axyridis) aka the Halloween beetle looks very similar to more common ladybugs, but they are generally bigger and with more spots. The bug is sitting on a yellow flower.
The Asian Lady Beetles (Harmonia axyridis) aka the Halloween beetles look very similar to more common ladybugs, but they are generally bigger and with more spots. Creative Touch Imaging Ltd./NurPhoto via Getty Images

How do you tell them apart?

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The Asian Lady Beetle (Harmonia axyridis) aka the Halloween beetle looks very similar to more common ladybugs, but they are generally bigger and with more spots. The bug is sitting on a yellow flower.
The Asian Lady Beetles (Harmonia axyridis) aka the Halloween beetles look very similar to more common ladybugs, but they are generally bigger and with more spots. Creative Touch Imaging Ltd./NurPhoto via Getty Images

Bats and spiders get most of the attention for Halloween and spooky season, but October is also ladybug time in many parts of the United States. Alongside their appropriately nicknamed cousins the “Halloween beetle,” residents from Wisconsin to North Carolina to New Hampshire historically report seeing more of these insects indoors this time of year. Here’s why.

[Related: These fold-up robots fly just like ladybugs.]

Looking for warmth

Ladybugs typically spend the warmer summer months outside in gardens and grasses. As fall settles in, the insects likely begin to seek a place to hibernate indoors when the temperatures begin to drop. 

They could also be looking for a safe and warm place to lay their eggs. According to This Old House, ladybugs will often leave a trail of pheromones that tells other ladybugs in the colony, “Hey, this place is safe, warm, and perfect for egg-laying,” when they find a good spot to lay eggs. 

They are most commonly spotted by doors and windows, where it is easy for them to squeeze inside under cracks. They can also hitch a ride on potted plants and flowers brought into the home.

How to tell a ladybug from a Halloween beetle

The more well-known and common seven spotted ladybugs (Hippodamia convergens) are often confused with their cousins the Asian lady beetle aka harlequin ladybird or the Halloween beetle (Harmonia axyridis). These bugs are also red, but can also appear more orange and have more spots on their backs. It is also more typical for them to swarm houses in the fall and before the winter. Both species are members of the Coccinellidae family of beetles, but belong to a different genus. 

The easiest way to tell the two cousins apart is to look at their spots. If there are more spots, it’s a Halloween beetle. If there are only seven, it’s a ladybug. You can also look around their “neck.” Halloween beetles have different markings that look a bit like a butterfly or a black “M.” They are also generally larger than ladybugs. 

Ladybugs also typically have a rounded or oval shape. Halloween beetles also have an oval appearance, but they are slightly longer with a pointed head and snout. 

According to University of Kentucky entomologists, Asian lady beetles seem to be attracted to lit up surfaces that have a light-dark surface contrast. Homes that are partially illuminated by the sun are then attractive to the beatles. 

[Related: How many ants are there on Earth? Thousands of billions.]

“Once the beetles alight on buildings, they seek out crevices and protected places to spend the winter. They often congregate in attics, wall cavities, and other protected locations,” the entomologists told WBIR-TV in Knoxville, Tennessee. “Since lady beetles are attracted to light, they are often seen around windows and light fixtures.”

Can they hurt me or my house?

Ladybugs do more good than harm. They do not carry any diseases and they are a garden’s best friend, by eating aphids and worms that can ruin spring flowers and veggies. Halloween beetles are generally more likely to infest a home. 

They are not typically aggressive to humans, but Halloween beetles can bite if they feel trapped or threatened. Like other insects, their bites can create small, red, and itchy marks. 

Halloween beetles can also harm furniture or carpets with their secretions. Some safe ways to keep them away include planting mums, lavender, bay leaves, cloves, citronella, and plants in the citrus and mint families to naturally repel ladybugs, sealing entry points to your home, and using door sweeps at the bottom of doors. 

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Your brain’s ‘master switchboard’ is an underappreciated marvel https://www.popsci.com/science/hypothalamus-brain-regulation/ Thu, 26 Oct 2023 21:00:00 +0000 https://www.popsci.com/?p=583628
A clock-like brain indicates its role in sleep in an illustration.
he brain area called the hypothalamus regulates important behaviors, including sleeping. Depositphotos

When you're sleepy or hungry, that's the hypothalamus at work.

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A clock-like brain indicates its role in sleep in an illustration.
he brain area called the hypothalamus regulates important behaviors, including sleeping. Depositphotos

Before your most recent meal, you might have felt some hunger pangs, signaling it was time to eat. Maybe you developed a sudden craving for Italian or another cuisine. These cues did not come out of thin air—they are the work of an almond-sized region in the brain called the hypothalamus. This area of the brain, despite its tiny size, has an enormous job in keeping us alive.

Nicknamed the master switchboard, the hypothalamus works in the background making sure our bodies are in the best condition possible. And, like the way many background actors are kept on the edges of a frame, its role has been taken for granted in the science community. “The hypothalamus is a very underappreciated region,” says Dayu Lin, a professor in the department of neuroscience and physiology at the NYU Grossman School of Medicine. She’s seen research interest in the brain region wane, with some even considering it to be less interesting compared to areas involved in higher and complex cognition.

But there’s still much more we have yet to uncover about the hypothalamus, as four review papers show in a series published by the journal Science today. Advanced technology has opened up new ways of examining the small brain region, redefining its old roles and identifying previously unknown ones. 

The body’s regulator

The hypothalamus controls a variety of vital processes. Working with the pituitary gland, it’s in charge of all hormone production. It is also involved in controlling temperature, blood pressure, heart rate, appetite, and other parts of our physiology. 

“The hypothalamus is regarded as an integral element in central nervous system control of both bodily hormonal activity, as well as a number of cognitive, emotional, and behavioral states,” says James Giordano, a Pellegrino Center professor of neurology at Georgetown University Medical Center, who was not involved in the current studies. 

Complex structures and circuits give the hypothalamus a wide range of influence over multiple bodily processes, the first new paper shows. The hypothalamus is divided into a cluster of cell bodies, called nuclei, with intersecting pathways that help it communicate and coordinate activity within itself and with other outside brain regions. “Hypothalamic function is critical to the integrative activity of the brain, and in this way can be seen as important to defining the integrity of body to brain, and brain to body activity,” Giordano adds.

[Related: New human brain atlas is the most detailed one we’ve seen yet]

Until now, a lack of scientific resources prevented researchers from understanding the function of these cells. Lin, who co-authored another paper on the brain region’s role in social behavior, said it was difficult to study what was going on in this area without disrupting the communication between cells. Past research relied on animals with lesions in specific areas of the hypothalamus, but this does not give a full picture of how the removed cells interact with the rest of the region. 

The 2009 invention of single-cell RNA sequencing, a laboratory technique that allows scientists to analyze the genetic information of individual cells, has helped in better dissecting the circuitry that give hypothalamic clusters their diverse functions. In the recent work, researchers have mapped the cell subtypes in the hypothalamus based on. The next challenges will be to figure out why certain cell types group together and how the clumps govern different behaviors.

This isn’t the only new tool that these scientists employed. Another new research technique, optogenetics, allows neuroscientists to use light to monitor brain cell activity. A third, retrograde tracing, uses a virus to track neural connections starting from synapses all the way to their cell bodies, which helped identify never-before-seen circuits. In the future, these could reveal the hypothalamus’s other roles in regulating behaviors that include pain responses and anxiety. At the same time, the study authors speculate that the hypothalamus directly connects to the gut microbiome, with the implication that this brain area would be in charge of gut bacterial effects as well as serotonin and other hormones involved in the regulation of food. 

Sleep, socialization, and goals

The other three papers focus on some of this brain controller’s major functions. Sleep, for example, is governed by specific neurons that act as a “switch” for transition from rest to wakefulness. But that’s not their only purpose. Sleep-wake cells are equally involved with other hypothalamic activities such as the control of energy metabolism and core body temperature.

“Our manuscript highlights the fact that most neuronal circuits in the hypothalamus serve more than one function, and that they are all interconnected,” says Luis de Lecea, a professor of psychiatry and behavioral sciences at Stanford University who served as author of the new review article. “Sleep is [also] intertwined with pretty much all brain function and loss of sleep affects many aspects of our health including aging and neurodegeneration.”

Another review article focused on how the hypothalamus can promote motivation towards necessities for us to survive such as food and water. To aim us toward such goals, the hypothalamus organizes its neural circuits to work with the ventral tegmental area, a part of the brain involved with reward processes. Optogenetic stimulation has revealed the hypothalamus sends messages to the ventral tegmental area that reinforce or inhibit motivation, and could explain food-seeking behavior. 

[Related: Psychedelics and anesthetics cause unexpected chemical reactions in the brain]

It also influences how we interact with others in a range of social behaviors. These can involve friendly and parental interactions, or aggressive or sexual actions. “These behaviors are critical for the animals to survive in the community and reproduce. The hypothalamus is essential for mediating these daily interactions,” says Lin, a co-author of this paper.

In that research, Lin proposes a dual-control system between the hypothalamus and brainstem-spinal cord. When someone spots a person they want to interact with, the hypothalamus engages with the dopamine system—dopamine is important for movements and reward—to maintain social interest and reinforce other socially acceptable actions. The brainstem-spinal cord circuit then takes this information and uses it to guide socially favorable responses and actions.

From lab animals to human health

Much of the work in investigating the ins and outs of the hypothalamus are in animals. Transgenic mice—genetically manipulated animals used to study biological processes and human diseases—make it easier for scientists to examine a specific section of the hypothalamus, Lin says, without putting any creatures under anesthesia. This is especially helpful to study communal behaviors, because animals need to be freely moving for their social brain circuits to activate. 

Although these studies originated in animals, the new information about the hypothalamus is already being used to form treatments for humans. Efforts are underway to use deep-brain stimulation to target the posterior end of the hypothalamus to prevent or reduce aggression, for example. There is also potential in targeting specific circuits in the hypothalamus to stop other problems such as insomnia and addiction. In the next 10 years, Lin predicts, we’ll be hearing more news of clinical trials that target the hypothalamus to treat troubling behaviors.

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Wild chimpanzees show signs of potential menopause—a rarity in the animal kingdom https://www.popsci.com/environment/wild-chimpanzees-menopause/ Thu, 26 Oct 2023 18:00:00 +0000 https://www.popsci.com/?p=583524
Ma Rainey, a post-reproductive female of the Ngogo community of chimpanzees in Kibale National Park, Uganda, and her adult son Wes. The two are sitting among trees in a forest.
Ma Rainey, a post-reproductive female of the Ngogo community of chimpanzees in Kibale National Park, Uganda, and her adult son Wes. Kevin Langergraber/Arizona State University

The evolutionary benefits of living after reproductive age are still debated.

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Ma Rainey, a post-reproductive female of the Ngogo community of chimpanzees in Kibale National Park, Uganda, and her adult son Wes. The two are sitting among trees in a forest.
Ma Rainey, a post-reproductive female of the Ngogo community of chimpanzees in Kibale National Park, Uganda, and her adult son Wes. Kevin Langergraber/Arizona State University

Living long lives past reproductive age is a real rarity for female members of the animal kingdom. Humans and some species of toothed whales are the only known animals to go through menopause and the reasons behind it are an evolutionary puzzle. A team of primatologists recently found that a group of wild chimpanzees in Uganda also show signs of menopause. The findings are described in a study published October 26 in the journal Science and could provide more insight into this rare biological phenomenon.

[Related: Adolescent chimpanzees might be less impulsive than human teens.]

In humans, menopause typically occurs between the ages of 45 and 55 and is characterized by a natural decline in reproductive hormones and the end of ovarian functions. Some symptoms in humans include chills, hot flashes, weight gain, and thinning hair. The evolutionary benefits of this process are still a mystery for biologists. It is also still unclear why menopause evolved in humans but not in other known long-lived primates. 

“During our ongoing twenty five year study of chimpanzees at Ngogo in Kibale National Park, Uganda, we noticed that many old females did not reproduce for decades,” study co-author and Arizona State University primatologist Kevin Langergraber tells PopSci. “It’s a surprising trait from the perspective of evolution: how and why can natural selection favor the extension of lifespan past the point at which individuals can no longer reproduce? We need to know in what species it occurs and which it doesn’t as a first step [to that question].”

To look closer, the authors calculated a metric called the post-reproductive representation (PrR). This measurement is the average proportion of adult lifespan that an animal spends in its post-reproductive state. Most mammals have a PrR close to zero, but the team found that Ngogo chimpanzees have a PrR of 0.2. This means that the female chimpanzees in this group live 20 percent of their adult years in a post-reproductive state

Urine samples from 66 female chimpanzees from different stages in their reproductive lives also showed that the transition to this post-reproductive state was marked by changes in hormones like gonadotropins, estrogens, and progestins. 

While similar hormonal variations are also a way to tell that this transition is happening in humans, the post-reproductive chimpanzees were not involved in raising their offspring’s children. In these chimpanzees, the common grandmother hypothesis, where females live longer after menopause to help take care of future generations, does not appear to apply. This contrasts with some populations of orca whales, where grandmothers are a critical part of raising their offspring’s young to ensure their survival

[Related: Nice chimps finish last—so why aren’t all of them mean?]

According to the team, there are two possible explanations for these longer post-reproductive lifespans. Chimpanzees and other mammals in captivity can have artificially long post-reproductive lifespans because they are protected from natural predators and some pathogens. Even though they’re a wild population, the Ngogo chimpanzees could also be similarly protected and live artificially long lives. They live in a relatively remote area that is undisturbed by logging and hunting by humans and are exposed to fewer human pathogens. Their current habitat could also be closer to what existed in their evolutionary past compared with other populations of primates that are more affected by humans.

“The study both illuminates and raises questions about the evolution of menopause,” University of Exeter evolutionary biologist Michael Cant wrote in a related review on the study. “It also highlights the power of difficult long-term field studies–often run on small budgets and at constant risk of closure–to transform fundamental understanding of human biology and behavior.” Cant is not an author of the study.

Langergraber says future studies like this one could answer the question of how common substantial post-reproductive lifespans have been throughout chimpanzee evolutionary history and if impacts from humans have kept their survivorship rates artificially low.

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Bumblebees carbo-load on the fly https://www.popsci.com/environment/bumblebees-calories/ Tue, 24 Oct 2023 15:00:00 +0000 https://www.popsci.com/?p=582503
A fuzzy yellow and black bumblebee foraging on a green plant.
Bumblebees make decisions about nectar sources “on the fly.”. Deposit Photos

They use their sesame seed-sized brains to prioritize getting the most calories as quickly as possible.

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A fuzzy yellow and black bumblebee foraging on a green plant.
Bumblebees make decisions about nectar sources “on the fly.”. Deposit Photos

When foraging, bumblebees often have a choice to make. Do they go for the nectar that is the easiest to get, or should they work harder to get nectar with a higher sugar content? A new study found that the priority for the bumblebees is getting the most calories in the shortest amount of time, even at the expense of using up more energy. This trade-off ensures an immediate energy boost for the bumblebee colony, according to a study published October 24 in the journal iScience.

[Related: Female honeybees may pass down ‘altruistic’ genes.]

The study looked at a common species in the United Kingdom called Bombus terrestris or the buff-tailed bumblebee. Bumblebees will drink nectar from flowers and regurgitate it into their nest for other bees to use. They only store a small amount of nectar in their nests, so they must make the most of every opportunity to forage. 

To make these choices, bumblebees appear to trade off the time that they spend collecting nectar with the energy content of that nectar. If the sugar content is worth it, the bees will work to collect it despite being more difficult to access. By comparison, honeybees make their foraging decisions by optimizing the amount of energy they are expelling for any nectar, likely to prolong a honeybee’s working life.  

Drinking while hovering takes more time and energy, while landing and being still is quicker and requires much less effort. The bumblebee tries to drink from the vertical flower. If the nectar reward on the vertical flowers is not worth spending the extra time to collect, bumblebees will give up and forage from the horizontal flowers instead. CREDIT: Hamish Symington.

“Bumblebees can make decisions ‘on the fly’ about which nectar sources are the most energetically economical,” study co-author and University of Oxford bee biologist Jonathan Pattrick said in a statement. “By training bumblebees to visit artificial slippery flowers and using different ‘nectars’ with high, medium or low amounts of sugar, we found that they could make a trade-off between the energy content of the nectar and how difficult it was to access.”

For the study, Patrick and a team of biologists made 60,000 observations of the bumblebee’s behavior over six months. This allowed them to precisely estimate bumblebee foraging energetics and each bumblebee in the study was observed for up to eight hours a day without a break. The team used artificial flowers that were positioned vertically and horizontally and had slippery surfaces that made it difficult for the bees to grip. 

A computer program measured the split-second timing as the bees flew between the fake flowers and foraged for nectar to see how much energy the bumblebees spent flying and how much they collected while drinking. They then identified how the bees decided whether to spend extra time and energy collecting high-sugar nectar from the slippery flowers, or take the easier option of collecting lower-sugar nectar from flowers they could land on.

Each bumblebee was then given one of three tests.

In test one, the nectar on both the vertical and horizontal artificial flowers contained the same amount of sugar. The bumblebees chose to forage from the horizontal flowers instead of spending the extra time and energy hovering around the vertical flowers.

In test two, the vertical flowers had much more sugary nectar than the horizontal flowers and the bumblebees chose to drink almost exclusively from the vertical flowers.

[Related: Bee brains could teach robots to make split-second decisions.]

In test three, the vertical flowers had slightly more sugary nectar than the horizontal flowers. This created a situation where the bumblebees had to make a tradeoff between the time and energy they spent foraging and the energy content in the nectar they were drinking. They ended up feeding from the horizontal flowers.

Based on these test results, the authors conclude that the bumblebees can choose to spend additional time and energy foraging from the more hard-to-access nectar sources, but only if the eventual reward is really worth it. Understanding how this works can help make predictions about what types of flowers the bumblebees are likely to visit and inform choices of the kinds of flowers planted to make fields more bumblebee friendly.

“It’s amazing that even with a brain smaller than a sesame seed, bumblebees can make such complex decisions,” study co-author and University of Cambridge biochemist Hamish Symington said in a statement. “It’s clear that bumblebee foraging isn’t based on a simple idea that ‘the more sugar there is in nectar, the better’ – it’s much more subtle than that. And it highlights that there’s still so much to learn about insect behavior.”

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This Jurassic-era ‘sea murderer’ was among the first of its kind https://www.popsci.com/environment/lorrainosaurus/ Mon, 23 Oct 2023 19:00:00 +0000 https://www.popsci.com/?p=582558
A life-sized reconstruction of the head and jaws of the oldest megapredatory pliosaur called Lorrainosaurus. The reptile is long and torpedo shaped, with closed jaws and sharp exposed teeth.
A life-sized reconstruction of the head and jaws of the oldest megapredatory pliosaur called Lorrainosaurus. Model By 10 Tons

Lorrainosaurus stalked the seas that cover present-day Europe and were the ecological equivalents of today’s killer whales.

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A life-sized reconstruction of the head and jaws of the oldest megapredatory pliosaur called Lorrainosaurus. The reptile is long and torpedo shaped, with closed jaws and sharp exposed teeth.
A life-sized reconstruction of the head and jaws of the oldest megapredatory pliosaur called Lorrainosaurus. Model By 10 Tons

With its 19 feet-long torpedo-shaped body and long teeth the newly-described Lorrainosaurus was a fearsome mega predator. The fossilized remains of a 170-million-year-old marine reptile is the oldest-known pliosaur and dates back to the Jurassic era. The discovery is described in a study published October 16 in the journal Scientific Reports.

[Related: Millions of years ago, marine reptiles may have used Nevada as a birthing ground.]

Pliosaurs were members of a group of ocean-dwelling reptiles that are closely related to the more famous long-necked plesiosaurs. Unlike their cousins, these pliosaurs had short necks and massive skulls. From snout to tail, it was likely about 19 feet long and very little is known about the plesiosaurs from this time.

“Famous examples, such as Pliosaurus and Kronosaurus–some of the world’s largest pliosaurs–were absolutely enormous with body-lengths exceeding 10m [32 feet]. They were ecological equivalents of today’s killer whales and would have eaten a range of prey including squid-like cephalopods, large fish and other marine reptiles. These have all been found as preserved gut contents,” study co-author and Uppsala University paleontologist Benjamin Kear said in a statement.

An illustration of tje oldest megapredatory pliosaur, Lorrainosaurus, in the sea that covered what is now northern France 170 million years ago. The reptile has large jaws that are open, bearing two rows of very sharp teeth and four pectoral fins.
The oldest megapredatory pliosaur, Lorrainosaurus, in the sea that covered what is now northern France 170 million years ago. CREDIT: Joschua Knüppe

Pliosaurs first emerged over 200 million years ago and remained relatively small players in marine ecosystems. Following a landmark restructuring of the marine predator ecosystem in the early to middle Jurassic era (about 175 to 171 million years ago) they reached apex predator status.

“This event profoundly affected many marine reptile groups and brought mega predatory pliosaurids to dominance over ‘fish-like’ ichthyosaurs, ancient marine crocodile relatives, and other large-bodied predatory plesiosaurs,” study co-author and paleobiologist at the Institute of Paleobiology of the Polish Academy of Sciences Daniel Madzia said in a statement.

The fossils in this study were originally found in 1983 in northeastern France, but were recently analyzed by an international team of paleontologists who identified this new pliosaur genus called Lorrainosaurus. The teeth and bones represent what was once a complete skeleton that decomposed and was spread along the ancient seafloor by scavengers and ocean currents. 

[Related: The planet’s first filter feeder could be this extinct marine reptile.]

Lorrainosaurus was one of the first truly huge pliosaurs. It gave rise to a dynasty of marine reptile mega-predators that ruled the oceans for around 80 million years,” Sven Sachs, a study co-author and paleontologist from the Naturkunde-Museum Bielefeld in Germany, said in a statement.

Other than a short report published in 1994, these fossils remained obscure until the team reevaluated the specimens. Finding Lorrainosaurus’ remains indicates that the reign of gigantic mega-predatory pliosaurs likely began earlier than paleontologists previously thought. These giants were also locally responsive to the major ecological changes in the marine environments that covered present day Europe during the early Middle Jurassic.

Lorrainosaurus is thus a critical addition to our knowledge of ancient marine reptiles from a time in the Age of Dinosaurs that has as yet been incompletely understood,” said Kear.

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Prehistoric shark called Kentucky home 337 million years ago https://www.popsci.com/science/new-shark-kentucky/ Fri, 20 Oct 2023 15:00:00 +0000 https://www.popsci.com/?p=581547
An illustration of a newly discovered shark species called Strigilodus tollesonae. The shark looks somewhat like a stingray, with outstretched wings, fan-like top fins, and a long tail with black spots.
An artist’s illustration of Strigilodus tollesonae. The new species is more closely related to modern ratfish than to other modern sharks and rays. Benji Paysnoe/NPS

Newly discovered Strigilodus tollesonae had petal-shaped teeth.

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An illustration of a newly discovered shark species called Strigilodus tollesonae. The shark looks somewhat like a stingray, with outstretched wings, fan-like top fins, and a long tail with black spots.
An artist’s illustration of Strigilodus tollesonae. The new species is more closely related to modern ratfish than to other modern sharks and rays. Benji Paysnoe/NPS

A group of paleontologists, park rangers, and geologists have discovered a new species of ancient shark in the rock layers of Mammoth Cave National Park in Kentucky. It was uncovered in a large fossil deposit that includes at least 40 different species of shark and their relatives, and even well-preserved skeletal cartilage. 

[Related: Megalodons were likely warm-blooded, despite being stone-cold killers.]

The new species is named Strigilodus tollesonae and is a petalodont shark. These extinct  sharks had petal-shaped teeth and lived about 337 million years ago. According to the National Park Service, it is more closely related to present day ratfish than sharks or rays and it was identified from teeth found in the cave’s walls. Strigilodus tollesonae likely had teeth that included one rounded cusp used for clipping and a long, ridge inert side that crushed prey the way molars do. Paleontologists believe that it likely lived like modern day skates and fed on worms, bivalves, and small fish. 

Strigilodus tollesonae translates to “Tolleson’s Scraper Tooth” and it is named after Mammoth Cave National park guide Kelli Tolleson for her work in the paleontological study that uncovered the new species. 

The limestone caves that make up the 400-mile long Mammoth Cave System were formed about 325-million-years ago during the Late Paleozoic. Geologists call this time period the Mississippian Period, when shallow seas covered much of North America including where Mammoth Cave is today. 

In 2019, the park began a major paleontological resources inventory to identify the numerous types of fossils associated with the rock layers. Mammoth Cave park staff reported a few fossil shark teeth that were exposed in the cave walls of Ste. Genevieve Limestone in several locations. Shark fossils can be difficult to come by, since shark skeletons are made of cartilage instead of bone. Cartilage is not as tough as bone, so it is generally not well-preserved in the fossil record. 

An artist’s illustration of an ancient sea that covered much of North America during the Mississippian age. A decaying shark lies on the bottom of the sea, with three live sharks and other fish swimming nearby.
The Mississippian age ancient sea and marine life preserved at Mammoth Cave National Park. CREDIT: Julius Csotonyi/NPS.

The team then brought in shark fossil specialist John-Paul Hodnett of the Maryland-National Capital Parks and Planning Commission to help identify the shark fossils. Hodnett and park rangers discovered and identified multiple different species of primitive sharks from the shark teeth and fine spine specimens in the rocks lining the cave passages.

“I am absolutely amazed at the diversity of sharks we see while exploring the passages that make up Mammoth Cave,” Hodnett said in a statement. “We can hardly move more than a couple of feet as another tooth or spine is spotted in the cave ceiling or wall. We are seeing a range of different species of chondrichthyans [cartilaginous fish] that fill a variety of ecological niches, from large predators to tiny little sharks that lived amongst the crinoid [sea lily] forest on the seafloor that was their habitat.”

[Related: This whale fossil could reveal evidence of a 15-million-year-old megalodon attack.]

In addition to Strigilodus tollesonae, the team have identified more than 40 different species of sharks and their relatives from Mammoth Cave specimens in the past 10 months. There appear to be at least six fossil shark species that are new to science. According to the team, those species will be described and named in an upcoming scientific publication.

The majority of the shark fossils have been discovered in areas of the park that are inaccessible to the public, so photographs, illustrations, and three-dimensional models have been made to display the discovery. The park also plans to celebrate the new shark fossils with multiple presentations and exhibits on Monday October 23

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Female honeybees may pass down ‘altruistic’ genes https://www.popsci.com/environment/honeybees-altruism/ Wed, 18 Oct 2023 17:00:00 +0000 https://www.popsci.com/?p=580768
A group of worker bees surround the queen bee on a honeycomb. All worker honeybees are female and they can go to extreme lengths to serve their queen even shedding their own ovaries.
All worker honeybees are female and they can go to extreme lengths to serve their queen even shedding their own ovaries. Deposit Photos

Honeybee genes might make workers serve the queen above themselves.

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A group of worker bees surround the queen bee on a honeycomb. All worker honeybees are female and they can go to extreme lengths to serve their queen even shedding their own ovaries.
All worker honeybees are female and they can go to extreme lengths to serve their queen even shedding their own ovaries. Deposit Photos

Honeybees are a model of teamwork in nature, with their complex society and hives that generate enough energy to create an electrical charge. They also appear to be some of the rare animals that display a unique trait of altruism, which is genetically inherited. The findings were described in a study published September 25 in the journal Molecular Ecology.

[Related: Bee brains could teach robots to make split-second decisions.]

Giving it all for the queen bee

According to the American Psychological Association, humans display altruism through behaviors that benefit another individual at a cost to oneself. Some psychologists consider it a uniquely human trait and studying it in animals requires a different framework for understanding. Animals experience a different level of cognition, so what drives humans to be altruistic might be different than what influences animals like honeybees to act in ways that appear to be altruistic.

In this new study, the researchers first looked at the genetics behind retinue behavior in worker honeybees. Retinue behavior is the actions of worker bees taking care of the queen, like feeding or grooming her. It’s believed to be triggered by specific pheromones and worker bees are always female. 

After the worker bees are exposed to the queen’s mandibular pheromone (QMP), they deactivate their own ovaries. They then help spread the QMP around to the other worker bees and they only take care of the eggs that the queen bee produces. Entomologists consider this behavior ‘altruistic’ because it benefits the queen’s ability to produce offspring, while the worker bees remain sterile. 

The queen is also typically the mother of all or mostly all of the honeybees in the hive. The genes that make worker bees more receptive to the queen’s pheromone and retinue behavior can be passed down from either female or male parent. However, the genes only result in altruistic behavior when they are passed down from the female bee parent.

“People often think about different phenotypes being the result of differences in gene sequences or the environment. But what this study shows is it’s not just differences in the gene itself—it’s which parent the gene is inherited from,” study co-author and Penn State University doctoral candidate Sean Bresnahan said in a statement. “By the very nature of the insect getting the gene from its mom, regardless of what the gene sequence is, it’s possibly going to behave differently than the copy of the gene from the dad.”

A battle of genetics 

The study supports a theory called the Kinship Theory of Intragenomic Conflict. It suggests that a mothers’ and fathers’ genes are in a conflict over what behaviors to support and not support. Previous studies have shown that genes from males can support selfish behavior in mammals, plants, and honeybees. This new study is the first known research that shows females can pass altruistic behavior onto their offspring in their genes. 

[Really: What busy bees’ brains can teach us about human evolution.]

Worker bees generally have the same mother but different fathers, since the queen mates with multiple male bees. This means that the worker bees share more of their mother’s genes with each other. 

“This is why the Kinship Theory of Intragenomic Conflict predicts that genes inherited from the mother will support altruistic behavior in honeybees,” Breshnahan said. “A worker bee benefits more from helping, rather than competing with, her mother and sisters—who carry more copies of the worker’s genes than she could ever reproduce on her own. In contrast, in species where the female mates only once, it is instead the father’s genes that are predicted to support altruistic behavior.”

Pinpointing conflict networks

To look closer, the team crossbred six different lineages of honeybees. Bresnahan says that this is relatively easy to do in mammals or plants, but more difficult in insects. They used honeybee breeding expertise from co-author Juliana Rangel from Texas A&M University and Robyn Underwood at Penn State Extension to create these populations.

Once the bee populations were successfully crossed and the offspring were old enough, the team assessed the worker bees’ responsiveness to the pheromone that triggers the retinue behavior. 

A female lab technician wearing a protective covering to keep her safe from bee stings points to a bee hive on a rooftop lab.
Penn State Grozinger lab technician Kate Anton inspectS a hive on the rooftop of Millennium Science Complex at Penn State University. CREDIT: Brennan Dincher

“So, we could develop personalized genomes for the parents, and then map back the workers’ gene expression to each parent and find out which parent’s copy of that gene is being expressed,” Bresnahan said.

The team identified the gene regulatory networks that have this intragenomic conflict, finding that more genes that have a parental bias were expressed. These networks consisted of genes that previous research showed were related to the retinue behavior.

“Observing intragenomic conflict is very difficult, and so there are very few studies examining the role it plays in creating variation in behavior and other traits,” study co-author and Penn State entomologist Christina Grozinger said in a statement. “The fact that this is the third behavior where we have found evidence that intragenomic conflict contributes to variation in honeybees suggests that intragenomic conflict might shape many types of traits in bees and other species.”

The team hopes that this research will help provide a blueprint for more studies into intragenomic conflict in other animals and plants.

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Unraveled nerves and mesmerizing caffeine crystals: 10 sensational glimpses of the microscopic realm https://www.popsci.com/science/10-microscopic-images-nikon-small-world-gallery/ Tue, 17 Oct 2023 14:00:00 +0000 https://www.popsci.com/?p=579496
A fluorescent microscopic image, magnified 20 times, of a rodent nerve.
Rodent optic nerve head showing astrocytes (yellow), contractile proteins (red) and retinal vasculature (green). Hassanain Qambari & Jayden Dickson/Nikon’s Small World Photomicrography Competition

Photos from the Nikon Small World competition reveal a world that appears unreal.

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A fluorescent microscopic image, magnified 20 times, of a rodent nerve.
Rodent optic nerve head showing astrocytes (yellow), contractile proteins (red) and retinal vasculature (green). Hassanain Qambari & Jayden Dickson/Nikon’s Small World Photomicrography Competition

For nearly half a century, Nikon’s Small World Photomicrography Competition has celebrated the beauty captured by extreme magnification. This year, the photomicrography contest was stacked: a panel of journalists and scientists selected winners from 1,900 entries submitted by researchers and photographers in 72 countries. Subjects as diverse as mutant fish, chemical reactions, and a speck of space rock became works of art when seen really, really up close.

Above, in first place, is a rodent’s optic nerve head. Blood vessels, each only 110 microns in diameter, radiate outward like the fizzing arms of a firework. The yellow star-like shapes surrounding the vessels are astrocytes, cellular helpers that maintain neuronal systems. Vision researchers at the Lions Eye Institute in Perth, Australia—Hassanain Qambari, assisted by Jayden Dickson—imaged the optic disc at 20x magnification as part of a study of diabetic retinopathy; this condition can cause blindness in people with diabetes.

“The visual system is a complex and highly specialized organ, with even relatively minor perturbations to the retinal circulation able to cause devastating vision loss,” Qambari said in a news release. “I entered the competition as a way to showcase the complexity of retinal microcirculation.” Below are other top photos, and you can see even more at Nikon’s Small World site.

A zebrafish head magnified 4x with purple and blue highlights.
20th place. Adult transgenic zebrafish head showing blood vessels (blue), lymphatic vessels (yellow), and the skin and scales (magenta). Imaged with a 4x objective lens. Daniel Castranova & Dr. Brant Weinstein/Nikon Small World Competition
A close-up of a match igniting.
2nd place. Matchstick igniting by the friction surface of the box. Imaged with a 2.5x objective lens. Ole Bielfeldt/Nikon Small World competition
Caffeine crystals under 25x magnification.
8th place. Caffeine crystals under 25x objective lens magnification. Stefan Eberhard/Nikon Small World Competition

[Related: 15 remarkable JWST images that reveal the wonders of our vast universe]

A rainbow of defensive hairs on a plant leaf.
5th place. Auto-fluorescing defensive hairs covering the leaf surface of the Russian olive, Eleagnus angustifolia, exposed to UV light. Imaged with 10x magnification. David Maitland/Nikon Small World competition
A black micrometeorite on a golden metal mesh.
18th place. A cryptocrystalline micrometeorite resting on a #80 testing sieve. Imaged with a 20x objective lens. Scott Peterson/Nikon Small World competition
9th place. Cytoskeleton of a dividing myoblast highlighting the cellular components tubulin (cyan), F-actin (orange) and nucleus (magenta), magnified 63x.
9th place. Cytoskeleton of a dividing myoblast highlighting the cellular components tubulin (cyan), F-actin (orange) and nucleus (magenta), magnified 63x. Vaibhav Deshmukh/Nikon Small World competition
Blue wave-like folds of a sugar syrup.
11th place. Crystallized sugar syrup in polarized light, seen via a 25x lens. Diego García/Nikon Small World competition
7th place. A mouse embryo imaged with 4x objective lens magnification.
7th place. A mouse embryo imaged with 4x objective lens magnification. Grigorii Timin & Michel Milinkovitch/Nikon Small World Competition
A spider fang, really zoomed in.
4th place. Venomous fangs of a small tarantula seen using 10x magnification. John-Oliver Dum/Nikon Small World competition

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12-million-year-old ape skull bares its fangs in virtual reconstruction https://www.popsci.com/science/12-million-year-old-ape-skull/ Mon, 16 Oct 2023 19:00:00 +0000 https://www.popsci.com/?p=579915
Three stage of digital reconstruction. From left, the Pierolapithecus cranium shortly after discovery, after initial preparation, and after virtual reconstruction.
From left, the Pierolapithecus cranium shortly after discovery, after initial preparation, and after virtual reconstruction. David Alba (left)/Salvador Moyà-Solà (middle)/Kelsey Pugh (right)

Now extinct, Pierolapithecus catalaunicus could be one of the earliest known members of the great ape and human family.

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Three stage of digital reconstruction. From left, the Pierolapithecus cranium shortly after discovery, after initial preparation, and after virtual reconstruction.
From left, the Pierolapithecus cranium shortly after discovery, after initial preparation, and after virtual reconstruction. David Alba (left)/Salvador Moyà-Solà (middle)/Kelsey Pugh (right)

A team of scientists from Spain and the United States reconstructed the skull of an extinct great ape species from a set of well-preserved, but damaged skeletal remains. The bones belonged to Pierolapithecus catalaunicus who lived roughly 12 million years ago. Studying its facial features could help us better understand human and ape evolution and the findings are described in a study published October 16 in the journal Proceedings of the National Academy of Sciences (PNAS).

[Related: This 7th-century teen was buried with serious bling—and we now know what she may have looked like.]

First described in 2004, Pierolapithecus was a member of a diverse group of extinct ape species that lived during the Miocene Epoch (about 15 to 7 million years ago) in Europe. During this time, horses were beginning to evolve in North America and the first dogs and bears also began to appear. The Miocene was also a critical time period for primate evolution.

In the study, the team used CT scans to virtually reconstruct Pierolapithecus’ cranium. They then used a process called principal components analysis and compared their digital reconstruction of the face with other primate species. They then modeled the changes occurring to some key features of ape facial structure. They found that Pierolapithecus shares similarities in its overall face shape and size with fossilized and living great apes. 

However, it also has distinct facial features that have not been found in other apes from the Middle Miocene. According to the authors, these results are consistent with the idea that Pierolapithecus represents one of the earliest members of the great ape and human family. 

“An interesting output of the evolutionary modeling in the study is that the cranium of Pierolapithecus is closer in shape and size to the ancestor from which living great apes and humans evolved,” study co-author and AMNH paleoanthropologist Sergio Almécija said in a statement. “On the other hand, gibbons and siamangs (the ‘lesser apes’) seem to be secondarily derived in relation to size reduction.”

Studying the physiology of extinct animals like Pierolapithecus can help us understand how other species evolved. This particular primate species is important because the team used a cranium and partial skeleton that belonged to the same individual ape, which is a rarity in the fossil record. 

[Related: Our tree-climbing ancestors evolved our abilities to throw far and reach high.]

“Features of the skull and teeth are extremely important in resolving the evolutionary relationships of fossil species, and when we find this material in association with bones of the rest of the skeleton, it gives us the opportunity to not only accurately place the species on the hominid family tree, but also to learn more about the biology of the animal in terms of, for example, how it was moving around its environment,” study co-author Kelsey Pugh said in a statement. Pugh is a primate palaeontologist with the American Museum of Natural History (AMNH) in New York and Brooklyn College.

Earlier studies on Pierolapithecus suggest that it could have stood upright and had multiple adaptations that allowed these hominids to hang from tree branches and move throughout them. However, Pierolapithecus’ evolutionary position is still debated, partially due to the damage to the specimen’s cranium.  

“One of the persistent issues in studies of ape and human evolution is that the fossil record is fragmentary, and many specimens are incompletely preserved and distorted,” study-coauthor and AMNH biological anthropologist Ashley Hammond said in a statement. “This makes it difficult to reach a consensus on the evolutionary relationships of key fossil apes that are essential to understanding ape and human evolution.”

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Galapagos giant tortoises are restoring their own ecosystem https://www.popsci.com/environment/galapagos-giant-tortoises-ecosystem-conservation/ Sun, 15 Oct 2023 22:00:00 +0000 https://www.popsci.com/?p=579488
A captive breeding program has seen the return of Galapagos giant tortoises to Española in the Galapagos Islands. As the tortoise population rebounds, the island ecosystem is in the process of transforming.
A captive breeding program has seen the return of Galapagos giant tortoises to Española in the Galapagos Islands. As the tortoise population rebounds, the island ecosystem is in the process of transforming. DepositPhotos

A decades-long project to reintroduce Galapagos giant tortoises is changing the face of the island of Española.

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A captive breeding program has seen the return of Galapagos giant tortoises to Española in the Galapagos Islands. As the tortoise population rebounds, the island ecosystem is in the process of transforming.
A captive breeding program has seen the return of Galapagos giant tortoises to Española in the Galapagos Islands. As the tortoise population rebounds, the island ecosystem is in the process of transforming. DepositPhotos

This article was originally featured on Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com.

In the late 19th century, whalers, settlers, and pirates changed the ecology of the Galapagos Islands by poaching some native species—like Galapagos giant tortoises—and introducing others, like goats and rats. The latter species became pests and severely destabilized the island ecosystems. Goats overgrazed the fruits and plants the tortoises ate while rats preyed on their eggs. Over time, the tortoise population plummeted. On Española, an island in the southeast of the archipelago, the tortoise count fell from over 10,000 to just 14. Along the way, with goats eating all the plants they could, Española—once akin to a savanna—turned barren.

A century later, conservationists set out to restore the Galapagos giant tortoise on Española—and the island ecosystem. They began eradicating the introduced species and capturing Española’s remaining tortoises and breeding them in captivity. With the goats wiped out and the tortoises in cages, the ecosystem transformed once again. This time, the overgrazed terrain became overgrown with densely packed trees and woody bushes. Española’s full recovery to its savanna-like state would have to wait for the tortoises’ return.

From the time those 14 tortoises were taken into captivity between 1963 and 1974 until they were finally released in 2020, conservationists with the NGO Galápagos Conservancy and the Galapagos National Park Directorate reintroduced nearly 2,000 captive-bred Galapagos giant tortoises to Española. Since then, the tortoises have continued to breed in the wild, causing the population to blossom to an estimated 3,000. They’ve also seen the ecology of Española transform once more as the tortoises are reducing the extent of woody plants, expanding the grasslands, and spreading the seeds of a key species.

Not only that, but the tortoises’ return has also helped the critically endangered waved albatross—a species that breeds exclusively on Española. During the island’s woody era, Maud Quinzin, a conservation geneticist who has previously worked with Galapagos tortoises, says that people had to repeatedly clear the areas the seabirds use as runways to take off and land. Now, if the landing strips are getting overgrown, they’ll move tortoises into the area to take care of it for them.

The secret to this success is that—much like beavers, brown bears, and elephants—giant tortoises are ecological architects. As they browse, poop, and plod about, they alter the landscape. They trample young trees and bushes before they can grow big enough to block the albatrosses’ way. The giant tortoises likewise have a potent impact on the giant species of prickly pear cactuses that call Española home—one of the tortoises’ favorite foods and an essential resource for the island’s other inhabitants.

When the tortoises graze the cactus’s fallen leaves, they prevent the paddle-shaped pads from taking root and competing with their parents. And, after they eat the cactus’s fruit, they drop the seeds across the island in balls of dung that offer a protective shell of fertilizer.

The extent of these and other ecological effects of the tortoise are documented in a new study by James Gibbs, a conservation scientist and the president of the Galápagos Conservancy, and Washington Tapia Aguilera, the director of the giant tortoise restoration program at the Galápagos Conservancy.

To study these impacts up close, they fenced off some of the island’s cactuses, which gave them a way to assess how the landscapes evolve when they’re either exposed to or free from the tortoises’ influences. They also studied satellite imagery of the island captured between 2006 and 2020 and found that while parts of the island are still seeing an increase in the density of bushes and trees, places where the tortoises have rebounded are more open and savanna-like.

As few as one or two tortoises per hectare, the scientists write, is enough to trigger a shift in the landscape.

Dennis Hansen, a conservation ecologist who has worked with the tortoises native to the Aldabra atoll in the Indian Ocean, says that while the findings line up with what conservationists expected, it was nice to have their suspicions confirmed. The results bode well for other rewilding projects that include giant tortoise restoration as a keystone of their efforts, he says, such as those underway on other islands in the Galapagos archipelago and on the Mascarene Islands in the Indian Ocean.

But on Española itself, though the tortoises have been busy stomping shoots and spreading seeds, they have more work to do. In 2020, 78 percent of Española was still dominated by woody vegetation. Gibbs says it may take another couple of centuries for Española’s giant tortoises to reestablish something like the ratio of grasses, trees, and bushes that existed before Europeans landed in the archipelago. But that long transformation is at least underway.

This article first appeared in Hakai Magazine and is republished here with permission.

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Climate change could help fungal diseases thrive https://www.popsci.com/environment/climate-change-fungal-diseases/ Sat, 14 Oct 2023 23:00:00 +0000 https://www.popsci.com/?p=579478
Rising temperatures are making conditions more favorable for disease-causing fungi — and may even be helping them adapt to infect people.
Rising temperatures are making conditions more favorable for disease-causing fungi — and may even be helping them adapt to infect people. DepositPhotos

Disease-causing fungi are likely to thrive in a warmer, stormier world — and more of them might be poised to make the leap to infecting people.

The post Climate change could help fungal diseases thrive appeared first on Popular Science.

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Rising temperatures are making conditions more favorable for disease-causing fungi — and may even be helping them adapt to infect people.
Rising temperatures are making conditions more favorable for disease-causing fungi — and may even be helping them adapt to infect people. DepositPhotos

This article originally appeared in Knowable Magazine.

Back at the turn of the 21st century, Valley fever was an obscure fungal disease in the United States, with fewer than 3,000 reported cases per year, mostly in California and Arizona. Two decades later, cases of Valley fever are exploding, increasing more than sevenfold and expanding to other states.

And Valley fever isn’t alone. Fungal diseases in general are appearing in places they have never been seen before, and previously harmless or mildly harmful fungi are turning deadly for people. One likely reason for this worsening fungal situation, scientists say, is climate change. Shifts in temperature and rainfall patterns are expanding where disease-causing fungi occur; climate-triggered calamities can help fungi disperse and reach more people; and warmer temperatures create opportunities for fungi to evolve into more dangerous agents of disease.

For a long time, fungi have been a neglected group of pathogens. By the early 2000s, researchers were already warning that climate change would make bacterial, viral and parasite-caused infectious diseases like cholera, dengue and malaria more widespread. “But people were not focused at all on the fungi,” says Arturo Casadevall, a microbiologist and immunologist at the Johns Hopkins Bloomberg School of Public Health. That’s because, until recently, fungi haven’t troubled humans much.

Our high body temperature helps explain why. Many fungi grow best at around 12 to 30 degrees Celsius (roughly 54 to 86 degrees Fahrenheit). So, while they find it easy to infect trees, crops, amphibians, fish, reptiles and insects — organisms that do not maintain consistently high internal body temperatures — fungi usually don’t thrive inside the warm bodies of mammals, Casadevall wrote in an overview of immunity to invasive fungal diseases in the 2022 Annual Review of Immunology. Among the few fungi that do infect humans, some dangerous ones, such as species of Cryptococcus, Penicillium and Aspergillus, have historically been reported more in tropical and subtropical regions than in cooler ones. This, too, suggests that climate may limit their reach.

Fungi on the move

Today, however, the planet’s warming climate may be helping some fungal pathogens spread to new areas. Take Valley fever, for instance. The disease can cause flu-like symptoms in people who breathe in the microscopic spores of the fungus Coccidioides. The climatic conditions favoring Valley fever may occur in 217 counties of 12 US states today, according to a recent study by Morgan Gorris, an Earth system scientist at the Los Alamos National Laboratory in New Mexico.

But when Gorris modeled where the fungi could live in the future, the results were sobering. By 2100, in a scenario where greenhouse gas emissions continue unabated, rising temperatures would allow Coccidioides to spread northward to 476 counties in 17 states. What was once thought to be a disease mostly restricted to the southwestern US could expand as far as the US-Canadian border in response to climate change, Gorris says. That was a real “wow moment,” she adds, because that would put millions more people at risk.

Biology photo

Some other fungal diseases of humans are also on the move, such as histoplasmosis and blastomycosis. Both, like Valley fever, are increasingly seen outside what was thought to be their historical range.

Such range extensions have also appeared in fungal pathogens of other species. The chytrid fungus that has contributed to declines in hundreds of amphibian species, for example, grows well at environmental temperatures between 17 and 25 degrees Celsius (63 to 77 degrees Fahrenheit). But the fungus is becoming an increasing problem at higher altitudes and latitudes, likely because rising temperatures are making previously cold regions more welcoming for the chytrid. Similarly, white pine blister rust, a fungus that has devastated some species of white pines across Europe and North America, is expanding to higher elevations where conditions were previously unfavorable. This has put more pine forests at risk. Changing climatic conditions are also helping drive fungal pathogens of crops, like those infecting bananas, potatoes and wheat, to new areas.

A warming climate also changes cycles of droughts and intense rains, which can increase the risk of fungal diseases in humans. One study of more than 81,000 cases of Valley fever in California between 2000 and 2020 found that infections tended to surge in the two years immediately following prolonged droughts. Scientists don’t yet fully understand why this happens. But one hypothesis suggests that Coccidioides survives better than its microbial competitors during long droughts, then grows quickly once rains return and releases spores into the air when the soil begins to dry again. “So climate is not only going to affect where it is, but how many cases we have from year to year,” says Gorris.

By triggering more intense and frequent storms and fires, climate change can also help fungal spores spread over longer distances. Doctors have observed unusually large outbreaks of Valley fever just after dust storms or other events that kick up clouds of dust. Similarly, researchers have found a surge in Valley fever infections in California hospitals after large wildfires as far as 200 miles away. Scientists have seen this phenomenon in other species too: Dust storms originating in Africa have been implicated in moving a coral-killing soil fungus to the Caribbean.

Researchers are now sampling the air in dust storms and wildfires to see if these events can actually carry viable, disease-causing fungi for long distances and bring them to people, causing infections. Understanding such dispersal is key to figuring out how diseases spread, says Bala Chaudhary, a fungal ecologist at Dartmouth College who coauthored an overview of fungal dispersal in the 2022 Annual Review of Ecology, Evolution, and Systematics. But there’s a long road ahead: Scientists still don’t have answers to several basic questions, such as where various pathogenic fungi live in the environment or the exact triggers that liberate fungal spores out of soil and transport them over long distances to become established in new places.

Evolving heat tolerance

Helping existing fungal diseases reach newer places isn’t the only effect of climate change. Warming temperatures can also help previously innocuous fungi evolve tolerance for heat and become deadlier. Researchers have long known that fungi are capable of this. In 2009, for example, researchers showed that a fungus — in this case a pathogen that infects hundreds of insect pests — could evolve to grow at 37 degrees Celsius, five degrees higher than its previous upper thermal limit, after just four months. More recently, researchers grew a dangerous human pathogen, Cryptococcus deneoformans, at both 37 degrees Celsius (similar to human body temperature) and 30 degrees Celsius in the lab. The higher temperature triggered a fivefold rise in mutations in the fungus’s DNA compared to the lower temperature. Rising global temperatures, the researchers speculate, could thus help some fungi rapidly adapt, increasing their ability to infect people.

There are examples from the real world too. Before 2000, the stripe rust fungus, which devastates wheat crops, was restricted to cool, wet parts of the world. But since 2000, certain strains of the fungus have become better adapted to higher temperatures. These sturdier strains have been replacing the older strains and spreading to new regions.

Biology photo

This is worrying, says Casadevall, especially with hotter days and heatwaves becoming more frequent and intense. “Microbes really have two choices: adapt or die,” he says. “Most of them have some capacity to adapt.” As climate change increases the number of hot days, evolution will select more strongly for heat-resistant fungi.

And as fungi in the environment adapt to tolerate heat, some might even become capable of breaching the human temperature barrier.

This may have happened already. In 2009, doctors in Japan isolated an unknown fungus from the ear discharge of a 70-year-old woman. This new-to-medicine fungus, which was given the name Candida auris, soon spread to hospitals around the world, causing life-threatening bloodstream infections in already sick patients. The World Health Organization now lists Candida auris among its most dangerous group of fungal pathogens, partly because the fungus is showing increasing resistance to common antifungal drugs.

“In the case of India, it’s really a nightmare,” says Arunaloke Chakrabarti, a medical mycologist at the Postgraduate Institute of Medical Education and Research in Chandigarh, India. When C. auris was first reported in India more than a decade ago, it was low on the list of Candida species threatening patients, Chakrabarti says, but now, it’s the leading cause of Candida infections. In the US, cases rose sharply from 63 between 2013 and 2016 to more than 2,300 in 2022.

Where did C. auris come from so suddenly? The fungus appeared simultaneously across three different continents. Each continent’s version of the fungus was genetically distinct, suggesting that it emerged independently on each continent. “It’s not like somebody took a plane and carried them,” says Casadevall. “The isolates are not related.”

Biology photo

Since all continents are exposed to the effects of climate change, Casadevall and his colleagues think that human-induced global warming may have played a role. C. auris may always have existed somewhere in the environment — potentially in wetlands, where researchers have recovered other pathogenic species of Candida. Climate change, they argued in 2019, may have exposed the fungus to hotter conditions over and over again, allowing some strains to become heat-tolerant enough to infect people.

Subsequently, scientists from India and Canada found C. auris in nature for the first time, in the Andaman Islands in the Bay of Bengal. This “wild” version of C. auris grew much slower at human body temperature than did the hospital versions. “What that suggests to me is that this stuff is all over the environment and some of the isolates are adapting faster than others,” says Casadevall.

Like other explanations for C. auris’s origin, Casadevall’s is only a hypothesis, says Chakrabarti, and still needs to be proved.

One way to establish the climate change link, Casadevall says, would be to review old soil samples and see if they have C. auris in them. If the older versions of the fungus don’t grow well at higher temperatures, but over time they start to, that would be good evidence that they’re adapting to heat.

In any case, the possibility of warmer temperatures bringing new fungal pathogens to humans needs to be taken seriously, says Casadevall — especially if drug-resistant fungi that currently infect species of insects and plants become capable of growing at human body temperature. “Then we find ourselves with organisms that we never knew before, like Candida auris.”

Doctors are already encountering novel fungal infections in people, such as five new-to-medicine species of Emergomyces that have appeared mostly in HIV-infected patients across four continents, and the first record of Chondrostereum purpureum — a fungus that infects some plants of the rose family — infecting a plant mycologist in India. Even though these emerging diseases haven’t been directly linked to climate change, they highlight the threat fungal diseases pose. For Casadevall, the message is clear: It’s time to pay more attention.

Editor’s note: This story was updated on September 27, 2023, to correct a mischaracterization of malaria. It is caused by a parasite, not a virus or a bacterium as was originally stated.

10.1146/knowable-092623-2

Shreya Dasgupta is an independent science journalist based in Bangalore, India.

This article originally appeared in Knowable Magazine, an independent journalistic endeavor from Annual Reviews. Sign up for the newsletter.

Knowable Magazine | Annual Reviews

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AI design for a ‘walking’ robot is a squishy purple glob https://www.popsci.com/technology/ai-robot-blob/ Fri, 13 Oct 2023 15:30:00 +0000 https://www.popsci.com/?p=579501
AI-designed multi-legged robots on table
They may not look like much, but they skipped past billions of years' of evolution to get those little legs. Northwestern University

During testing, the creation could walk half its body length per second—roughly half as fast as the average human stride.

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AI-designed multi-legged robots on table
They may not look like much, but they skipped past billions of years' of evolution to get those little legs. Northwestern University

Sam Kreigman and his colleagues made headlines a few years back with their “xenobots”— synthetic robots designed by AI and built from biological tissue samples. While experts continue to debate how to best classify such a creation, Kriegman’s team at Northwestern University has been hard at work on a similarly mind-bending project meshing artificial intelligence, evolutionary design, and robotics.

[Related: Meet xenobots, tiny machines made out of living parts.]

As detailed in a new paper published earlier this month in the Proceedings of the National Journal of Science, researchers recently tasked an AI model with a seemingly straightforward prompt: Design a robot capable of walking across a flat surface. Although the program delivered original, working examples within literal seconds, the new robots “[look] nothing like any animal that has ever walked the earth,” Kriegman said in Northwestern’s October 3 writeup.

And judging from video footage of the purple multi-“legged” blob-bots, it’s hard to disagree:

After offering their prompt to the AI program, the researchers simply watched it analyze and iterate upon a total of nine designs. Within just 26 seconds, the artificial intelligence managed to fast forward past billions of years of natural evolutionary biology to determine legged movement as the most effective method of mobility. From there, Kriegman’s team imported the final schematics into a 3D printer, which then molded a jiggly, soap bar-sized block of silicon imbued with pneumatically actuated musculature and three “legs.” Repeatedly pumping air in and out of the musculature caused the robots’ limbs to expand and contract, causing movement. During testing, the robot could walk half its body length per second—roughly half as fast as the average human stride.

“It’s interesting because we didn’t tell the AI that a robot should have legs,” Kriegman said. “It rediscovered that legs are a good way to move around on land. Legged locomotion is, in fact, the most efficient form of terrestrial movement.”

[Related: Disney’s new bipedal robot could have waddled out of a cartoon.]

If all this weren’t impressive enough, the process—dubbed “instant evolution” by Kriegman and colleagues—all took place on a “lightweight personal computer,” not a massive, energy-intensive supercomputer requiring huge datasets. According to Kreigman, previous AI-generated evolutionary bot designs could take weeks of trial and error using high-powered computing systems. 

“If combined with automated fabrication and scaled up to more challenging tasks, this advance promises near-instantaneous design, manufacture, and deployment of unique and useful machines for medical, environmental, vehicular, and space-based tasks,” Kriegman and co-authors wrote in their abstract.

“When people look at this robot, they might see a useless gadget,” Kriegman said. “I see the birth of a brand-new organism.”

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Neanderthals may have hunted mighty cave lions https://www.popsci.com/science/neanderthal-cave-lion-hunt/ Fri, 13 Oct 2023 13:00:00 +0000 https://www.popsci.com/?p=579416
The cave lion remains from Siegsdorf, Germany are displayed alongside a reproduction of a wooden spear similar to those used by Neanderthals.
The cave lion remains from Siegsdorf, Germany are displayed alongside a reproduction of a wooden spear similar to those used by Neanderthals. Volker Minkus/NLD

The fierce feline predators went extinct at the end of the last Ice Age.

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The cave lion remains from Siegsdorf, Germany are displayed alongside a reproduction of a wooden spear similar to those used by Neanderthals.
The cave lion remains from Siegsdorf, Germany are displayed alongside a reproduction of a wooden spear similar to those used by Neanderthals. Volker Minkus/NLD

Neanderthals cooked crab and created art, but they also could have haunted cave lions and used their skins. Some 48,000 year-old puncture wounds on a cave lion’s ribcage suggest that the big cat was killed by a Neanderthal’s wooden spear. The findings are described in a study published October 12 in the journal Scientific Reports and may be the earliest known example of lion hunting and butchering by these extinct humans.

[Related: Sensitive to pain? It could be your Neanderthal gene variants.]

For about 20,000 years, cave lions were the most dangerous animals in Eurasia, with a shoulder height of about 4.2 feet high. They lived in multiple environments and hunted large herbivores including mammoth, bison, hose, and cave bear. They get the name cave lions due to the fact that most of their bones have been found in Ice Age caves. The fearsome creatures went extinct at the end of the last Ice Age, but live on through their bones and the 34,000 rock art panels at Grotte Chauvet in France. 

In 1985, an almost complete cave lion skeleton was uncovered in Siegsdorf, Germany. The bones are believed to be from an old, medium-sized cave lion. There are cut marks across bones including two ribs, some vertebrae, and the left femur, which lead scientists to believe that ancient humans butchered the big cat after it died.  

However, the authors in this new study took another look at the remains. They describe a partial puncture wound located on the inside of the lion’s third rib. The wound appears to match the impact mark left by a wooden-tipped spear. The puncture is angled, which suggests that the spear entered the left of the lion’s abdomen and penetrated its vital organs before impacting the third rib on its right side. 

“The rib lesion clearly differs from bite marks of carnivores and shows the typical breakage pattern of a lesion caused by a hunting weapon,” Gabriele Russo, a study co-author and zooarchaeology PhD student at Universität Tübingen in Germany, said in a statement

The characteristics of the puncture wound also resemble the wounds found on deer vertebrae which are known to have been made by Neanderthal spears. The new findings could represent the earliest evidence of Neanderthals purposely hunting cave lions.

“The lion was probably killed by a spear that was thrust into the lion’s abdomen when it was already lying on the ground.” study co-author and University of Reading paleolithic archaeologist Annemieke Milks said in a statement

[Related: How many ancient humans does it take to fight off a giant hyena?]

The team also analyzed the findings from a 2019 excavation at the Unicorn Cave–or Einhornhöhle–in the Harz Mountains in Germany. The remains of several animals dating back to the last Ice Age or about 55,000 to 45,000 years ago were found, including some cave lion bones. They looked at bones from the toes and lower limbs of three cave lion specimens. These bones also had cut marks that are consistent with the markings generated when an animal is skinned.

The cut marks suggest that great care was taken while skinning the lion to ensure that the claws remained preserved within the fur. This finding could be the earliest evidence of Neanderthals using a lion pelt, potentially for cultural purposes.

“The interest of humans to gain respect and power from a lion trophy is rooted in Neanderthal behavior and until modern times the lion is a powerful symbol of rulers!” Thomas Terberger, a study co-author and archaeologist at the Universität Göttingen in Germany said in a statement

Future studies of cave lion bones could reveal more details of more complex Neanderthal behaviors and how the animal may have laid the basis for cultural development by our own species—Homo sapiens

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New human brain atlas is the most detailed one we’ve seen yet https://www.popsci.com/health/human-brain-cell-atlas/ Thu, 12 Oct 2023 19:15:00 +0000 https://www.popsci.com/?p=579123
A pinkish human brain against a black background.
One of the human brains examined in the suite of new studies that created the atlas. Lisa Keene and Amanda Kirkland of UW Medicine

The catalog of 3,000 cell types could be a game-changer for personalized medicine and animal models.

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A pinkish human brain against a black background.
One of the human brains examined in the suite of new studies that created the atlas. Lisa Keene and Amanda Kirkland of UW Medicine

We’re closer than ever to mapping the entire brain to the microscopic level. Hundreds of neuroscientists across the world recently characterized more than 3,000 human brain cell types as part of the National Institute of Health’s BRAIN Initiative Cell Census Network, publishing almost two dozen papers in four Science journals today. This super-focused attention to detail could unlock many mysteries surrounding that complex organ, such as what happened in our brains to distinguish us from other primates. 

“This is the first large-scale, detailed description of all the different kinds of cells present in the human brain,” says Rebecca Hodge, an assistant investigator at the Allen Institute in Seattle who co-authored multiple studies in the paper package. Her hope is that this brain atlas provides a community resource for scientists to explore how the wide variety of brain cells contribute to health and disease.

Mark Mapstone, a professor of neurology at University of California, Irvine School of Medicine, who wasn’t involved with these studies, likened the new data about the brain to a tourist’s guide. “Imagine navigating an unfamiliar city with a roughly drawn street map containing only the major streets of the downtown compared to navigating the same city with a detailed map extending beyond the downtown to the suburbs and including all highways, two-way and one-way streets, alleyways, sidewalks, location of street signs and traffic signals, speed limits, and location of coffee shops and restaurants,” he says. “Cleary, the latter would make navigation and understanding the city much easier.” This first suite of studies shows three main ways the brain map can be used for biology and medicine.

An evolving brain

A human brain atlas can teach us about our evolutionary history. One study published today in Science used single-nucleus RNA sequencing to measure the gene expression of individual brain cells in humans and five other primate species, including chimpanzees and gorillas. In this method, scientists pull out individual cells from a piece of tissue, break them open to expose the genetic messengers inside, then use tags akin to tiny barcodes to identify that material. “This is the main technology used in some of these papers that are coming out and it’s a technique that’s only been around for the past 10 years,” Hodge says. Getting this genetic profile allows researchers to group clusters of cells into specific types. 

[Related: Psychedelics and anesthetics cause unexpected chemical reactions in the brain]

Our cells’ composition and organization is similar to those of our close relatives. However, the biggest differences seemed to occur in a brain region called the middle temporal gyrus, which is involved in processing semantic memory and language. Humans had higher numbers of projecting neurons in this area compared to other species. What’s more, the researchers highlighted a difference in gene expression that promoted synaptic plasticity, which is the ability of neurons to strengthen brain connections. This feature is an important component for learning and memory, and it might explain how humans developed complex cognitive skills.

A scientific graphic showing human and marmoset gene expression.
The gene expression of a class of neurons in a human (top) and marmoset (bottom).

There was some variation within humans, too. Another study found the most differences across humans in immune cells called microglia as well as deep-layer excitatory neurons, which are involved in the communication between distant brain regions. Researchers are not quite sure why—one theory is that deep-layer excitatory neurons develop earlier and are more exposed to environmental factors that could diversify their gene patterns. “Everyone’s brain is largely similar. Even though we have the same building blocks, it’s the small number of differences that matter,” says Jeremy Miller, a senior scientist at the Allen Institute, and co-author of the study. “We’re now starting to understand how important these changes are and figuring out what makes us uniquely human.”

Animal models

Because human brains share many features with other mammals, neurologists frequently use the small brains of mice to study diseases. The one problem, Miller says, is that mice don’t naturally develop neurodegenerative diseases common in humans. Scientists who want to study Alzheimer’s disease, for example, would need to manipulate multiple mouse genes to cause the kind of brain pathology seen in older people. This requires a comprehensive understanding of how cell types in the brain work together and how they change in the context of disease. 

[Related: How your brain conjures dreams]

Much brain research in mice focuses on the neocortex, responsible for higher cognitive function. It might seem reasonable to assume that much of the brain’s cellular complexity appears here. But this doesn’t seem to be the case. In one of the first studies to create a cell map of the entire adult brain, neuroscientists have found high levels of diversity in older evolutionary structures such as the midbrain, which is involved in movement, vision, and hearing, and the hindbrain, which governs vital bodily functions such as breathing and heart rate. In subcortical areas, there also appears to be a supercluster of cells called splatter neurons that control innate behaviors and physiological functions. Replicating the complexity of these particular brain regions in animal models could help better identify the cellular origins of human diseases. 

Personalized medicine

Imagine a future where treatments are tailored to someone’s specific needs. To do that, scientists would use a person’s genetic profile, rather than characteristics such as weight or age, to inform any medical decisions. Clinicians could also use this genetic information to identify the risks of potential diseases and provide early preventative measures. 

“A detailed brain atlas can help us understand what successful brain function looks like so we can maximize brain cells and circuits that promote brain heath,” Mapstone says. “Addressing brain disease and promoting brain health can be more easily accomplished if we know how these cells are organized. “

A schematic of the brain and related diseases. In the bottom graph,
Cell type (x-axis) association with 19 neuropsychiatric disorders and traits
A schematic of brain cells and related diseases. The bottom graph shows cell type association with 19 neuropsychiatric disorders and traits; darker red indicates stronger associations. Yang (Eric) Li, Ren Lab, University of California San Diego

Doctors are already using people’s genetic information to assess whether patients would be good candidates for a particular cancer treatment or to find the proper dose of a drug. This may soon include testing for neurological conditions. One study, which analyzed 1.1 million cells in 42 brain regions of neurotypical adults, identified specific neuronal cell types—mainly in the basal ganglia, a region involved in addictive behaviors—that were linked to 19 neuropsychiatric disorders and traits. Those conditions included schizophrenia and bipolar disorder as well as alcohol and tobacco use disorder.

This project is a step in the right direction for advancing research in personalized medicine, says Miller, though he warns this is only one of many to make this a reality for everyone. 

Miller and Hodge are optimistic there will be other versions of the human brain atlas completed in the next five years, as other groups wrap up similar projects. 

But there’s a possibility that we’ll never get the full picture. While Miller finds a half-decade timeframe reasonable, he says there’s always a chance science develops a new technology that could unearth something unexpected about the brain. “We can always do more,” he says.

This post has been updated.

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Female frogs appear to play dead to avoid mating https://www.popsci.com/environment/female-frog-mating-play-dead/ Thu, 12 Oct 2023 16:00:00 +0000 https://www.popsci.com/?p=579103
Two frogs mating in a body of water.
The behavior could also be a way to test a male frog's strength and endurance. Deposit Photos

Other animals tend to 'play possum' to avoid being eaten.

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Two frogs mating in a body of water.
The behavior could also be a way to test a male frog's strength and endurance. Deposit Photos

To avoid the amphibian pile-up that often comes with mating, some female frogs take drastic measures. According to research published October 11 in the journal Royal Society Open Science, female European common frogs will lay completely still and play dead to fend off potential mates. 

[Related: Check out some of the weirdest warty frogs in North America.]

In the study, a team from the Natural History Museum of Berlin in Germany placed a male frog in a box with one large female and one small female and recorded the mating behavior. They observed 54 instances of female frogs being clutched by the males and 83 percent of females tried rotating their body when gripped. About 48 percent of clasped females emitted “release calls” like squeaks and grunts and all of these vocal frogs rotated their bodies. 

Thirty-three percent of the frogs clasped by male expressed tonic immobility. This is when a frog stiffens its outstretched arms and legs to appear dead. The immobility tended to occur alongside both rotating and calling. Smaller females more frequently used all three tactics together than the bigger frogs. 

Interestingly, this unusual behavior had actually been seen centuries before. “I found a book written in 1758 by Rösel von Rosenhoff describing this behavior, which was never mentioned again,” study co-author Carolin Dittrich told The Guardian. “It was previously thought that females were unable to choose or defend themselves against this male coercion. Females in these dense breeding aggregations are not passive as previously thought.”

The team acknowledges that this behavior could also be a way to test a male’s strength and endurance, as those traits could boost their survival chances. They also point out that a larger sample size is needed to see if smaller females are more successful at escaping. 

This playing tactic is also used by other animals as a way to avoid being eaten.

The phrase “playing possum”  refers to a tactic deployed by the North American opossum found in the United States and Canada. When this marsupial is threatened by a predator, it will throw itself onto its back, bare its teeth, drool, and excrete a very bad smelling liquid out of its anal glands to get out of danger. 

North American wood ducks and colorful mallard ducks can immediately collapse when confronted with predators. In a 1975 experiment, 29 out of 50 different wild ducks played dead when they were exposed to captive red foxes. The ducks would also stay still long enough to be brought back to the fox’s den and wait until later to escape. The veteran foxes quickly learned that they needed to quickly deal a fatal injury to ducks that appeared dead.

[Related: Why some tiny frogs have tarantulas as bodyguards.]

Despite being apex predators, multiple species of sharks and rays also exhibit tonic immobility. Lemon sharks will turn onto their back and exhibit labored breathing and an occasional tremor when facing danger. Zebra sharks will also do this and will even stay immobile when being transported. 

Male nuptial gift-giving spiders will display a different death feigning behavior called thanatosis. It’s part of a courtship ritual that begins before mating with potentially cannibalistic female spiders. In a 2006 experiment, the males would “drop dead” when a female approached with interest. When entering thanatosis, the males would collapse and remain completely still, while retaining a gift of prey the male has already caught and wrapped in silk The male only cautiously begins to move when the female ate the gifts and initiated copulation.

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Titanium-fused bone tissue connects this bionic hand directly to a patient’s nerves https://www.popsci.com/technology/bionic-hand-phantom-pain/ Thu, 12 Oct 2023 15:00:00 +0000 https://www.popsci.com/?p=579098
Patient wearing a highly integrated bionic hand in between many others
The breakthrough bionic limb relies on osseointegration to attach to its wearer. Ortiz-Catalan et al., Sci. Rob., 2023

Unlike other prosthetics, a new model connects directly to a patient's limb via both bone and nerves.

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Patient wearing a highly integrated bionic hand in between many others
The breakthrough bionic limb relies on osseointegration to attach to its wearer. Ortiz-Catalan et al., Sci. Rob., 2023

Adjusting to prosthetic limbs isn’t as simple as merely finding one that fits your particular body type and needs. Physical control and accuracy are major issues despite proper attachment, and sometimes patients’ bodies reject even the most high-end options available. Such was repeatedly the case for a Swedish patient after losing her right arm in a farming accident over two decades ago. For years, the woman suffered from severe pain and stress issues, likening the sensation to “constantly [having] my hand in a meat grinder.”

Phantom pain is an unfortunately common affliction for amputees, and is believed to originate from nervous system signal confusions between the spinal cord and brain. Although a body part is amputated, the peripheral nerve endings remain connected to the brain, and can thus misread that information as pain.

[Related: We’re surprisingly good at surviving amputations.]

With a new, major breakthrough in prosthetics, however, her severe phantom pains are dramatically alleviated thanks to an artificial arm built on titanium-fused bone tissue alongside rearranged nerves and muscles. As detailed in a new study published via Science Robotics, the remarkable advancements could provide a potential blueprint for many other amputees to adopt such technology in the coming years.

The patient’s procedure started in 2018 when she volunteered to test a new kind of bionic arm designed by a multidisciplinary team of engineers and surgeons led by Max Ortiz Catalan, head of neural prosthetics research at Australia’s Bionics Institute and founder of the Center for Bionics and Pain Research. Using osseointegration, a process infusing titanium into bone tissue to provide a strong mechanical connection, the team was able to attach their prototype to the remaining portion of her right limb.

Accomplishing even this step proved especially difficult because of the need to precisely align the volunteer’s radius and ulna. The team also needed to account for the small amount of space available to house the system’s components. Meanwhile, the limb’s nerves and muscles needed rearrangement to better direct the patient’s neurological motor control information into the prosthetic attachment.

“By combining osseointegration with reconstructive surgery, implanted electrodes, and AI, we can restore human function in an unprecedented way,” Rickard Brånemark, an MIT research affiliate and associate professor at Gothenburg University who oversaw the surgery, said via an update from the Bionics Institute. “The below elbow amputation level has particular challenges, and the level of functionality achieved marks an important milestone for the field of advanced extremity reconstructions as a whole.”

The patient said her breakthrough prosthetic can be comfortably worn all day, is highly integrated with her body, and has even relieved her chronic pain. According to Catalan, this reduction can be attributed to the team’s “integrated surgical and engineering approach” that allows [her] to use “somewhat the same neural resources” as she once did for her biological hand.

“I have better control over my prosthesis, but above all, my pain has decreased,” the patient explained. “Today, I need much less medication.” 

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Fierce mama Grazer takes 2023’s Fat Bear Week crown https://www.popsci.com/environment/fat-bear-week-winner-2023/ Wed, 11 Oct 2023 12:30:00 +0000 https://www.popsci.com/?p=578638
Grazer looking chunky and getting ready for winter on September 14, 2023. The bear is in the river intensely staring for salmon.
Grazer looking chunky and getting ready for winter on September 14, 2023. NPS Photo/F. Jimenez

'It was the year of the sow.'

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Grazer looking chunky and getting ready for winter on September 14, 2023. The bear is in the river intensely staring for salmon.
Grazer looking chunky and getting ready for winter on September 14, 2023. NPS Photo/F. Jimenez

Bear enthusiasts of the world have spoken—128 Grazer was just crowned the winner of Fat Bear Week 2023. This is Grazer’s first time wearing the crown, and she beat out runner up 32 Chunk in the fierce Fat Bear Tuesday final by over 85,000 votes.

[Related: It’s Fat Bear season again! This is the best feed to keep up with these hairy giants.]

According to the National Park Service, Grazer is a large adult female, boasting a long straight muzzle, light brown summer fur, and blond ears. During late summer and fall, she is often one of the fattest bears to feed on the plentiful salmon in the Brooks River in Alaska’s Katmai National Park and Preserve.

She is also a particularly defensive mother bear who has raised two litters of cubs. Grazer is known for preemptively confronting and attacking much larger bears—even the large and dominant adult males—to keep her cubs safe. One of Katmai’s adult males named 151 Walker even avoids her, even though she did not have any cubs to protect this season. 

An Instagram post from Katmai National Park and Preserve of the Fat Bear Week 2023 bracket, with bear 128 Grazer in the center.

Grazer is the third female bear, or sow, to win the tournament. In 2019, 435 Holly was dubbed fattest bear and 409 Beadnose wore the prestigious crown in 2018. Beadnose is believed to have died in the five years since. 

“The girls did really well this year,” media ranger at Katmai National Park and Preserve Naomi Boak told The Washington Post. “It was the year of the sow.”

Like any competition, this year’s voting was packed with twists and turns. Four-time Fat Bear Week Champion 480 Otis was ousted on Friday October 6. Otis is the oldest and among the park’s most famous bears. This year, he arrived at Brooks River very skinny, but transformed into a thick bear. Otis was beaten by bear 901, a new mom and the 2022 runner up. 

On Saturday October 7, the 2022 winner bear 747 was defeated by Grazer, who went on to beat 901, Holly, and Chunk in the Final Four. 

[Related: How scientists try to weigh some of the fattest bears on Earth.]

First launched by the National Park Service in 2014 as Fat Bear Tuesday, Fat Bear Week is an annual tournament-style bracket competition where the public votes for their favorite chubby bear. Its goal is to celebrate the Brooks River brown bears at Katmai in southern Alaska and its remarkable ecosystem. It was expanded Fat Bear Week in 2015, following the first year’s success. In 2022, over one million votes were cast all around the world. 

At Katmai, bears are drawn to the large number of salmon readily available from late June through September. Salmon have long since been the lifeblood of the area, supporting Katmai’s people, bears and other animals. Fat bears exemplify the richness of this area, a wild region that is home to more brown bears than people along with the largest, healthiest runs of sockeye salmon left on the planet. The daily lives of the Brooks River bears can be followed via eight live-streaming cameras on explore.org from June through October. 

The winners, and all the bears, now get six months of restful solitude as winter approaches. 

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Sensitive to pain? It could be your Neanderthal gene variants. https://www.popsci.com/science/neanderthal-genetics-pain-sensitivity/ Tue, 10 Oct 2023 17:00:00 +0000 https://www.popsci.com/?p=578280
Human hand bones during an archaeological dig.
Scientists are still not sure if carrying these ancient genetic variants and greater sensitivity to pain was an evolutionary advantage. Deposit Photos

Studying them could lead to a greater understanding of chronic pain.

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Human hand bones during an archaeological dig.
Scientists are still not sure if carrying these ancient genetic variants and greater sensitivity to pain was an evolutionary advantage. Deposit Photos

In the years since the Neanderthal genome was first sequenced, geneticists have been peering into the past to look for traces of this extinct group of humans within our genes. The presence of these ancient genes could make carriers more at risk for severe COVID-19, influence nose shape, and even make some people more sensitive to pain

[Related: Neanderthal genomes reveal family bonds from 54,000 years ago.]

A new study published October 10 in the journal Communications Biology found that those carrying three Neanderthal gene variants are actually more sensitive to pain from skin pricking after prior exposure to mustard oil. In this case, mustard oil acts as an agonist, or a substance that initiates a physiological response. Adding it to the skin causes a quick response by neurons called nociceptors that create a sense of pain. 

SCN9A is a key gene in the perception of pain that is located on chromosome 2. It is highly expressed nociceptors that are activated when a sharp point or something hot is applied to the body. The neurons encode proteins within the body’s sodium channel and alert the brain which leads to the perception of pain. Earlier research found three variations in the SCN9A gene–M932L, V991L, and D1908G–in sequenced Neanderthal genomes and reports of greater sensitivity to pain among the living humans who have all three of these variants. 

“It has been shown in previous studies that some rare mutations in this gene that stop the channel from working can cause insensitivity to pain,” study co-author and University of Oxford neuroscientist David Bennett tells PopSci. “We were, however, interested in these other mutations, which were shown to have an opposite effect of enhancing the activity of this channel, thus leading their carriers to be somewhat more sensitive than non-carriers.”

According to Andrés Ruiz-Linares, study co-author and University College London human geneticist, earlier studies show that the mutations are quite rare in the British populations, but they are very frequent in Latin American populations. 

“We thus realized that we had, in our hands, the perfect dataset to not only replicate their study but also go further and identify the pain modality that was at work here,” Ruiz-Linares tells PopSci

In the study, the team measured the pain thresholds of 1,963 individuals from Colombia in response to a range of stimuli. The D1908G variant was present in roughly 20 percent of chromosomes within this population. About 30 percent of chromosomes carrying this variant also carried the M932L and V991L variants. All three variants were associated with a lower pain threshold in response to skin pricking after the skin was exposed to mustard oil, but not in response to pressure or heat. Additionally, carrying all three of these variants was associated with greater pain sensitivity than carrying only one of them. 

[Related: Neanderthals were likely creating art 57,000 years ago.]

The team then analyzed the genomic region that houses SCN9A using genetic data from 5,971 individuals from Peru, Chile, Brazil, Colombia, and Mexico. They found that the three Neanderthal variants were more common in regions where the population had a higher proportion of Native American ancestry, such as the Peruvian population.

“They [the mutations] have a rather wide range in these countries, from 2 to 42 percent,” study co-author and University College London statistical geneticist Kaustubh Adhikari tells PopSci. “Up to 18 percent of their populations could carry two copies of the mutation. These are, however, gross estimations. We also know, from the previous study, that these mutations are pretty rare in European populations.”

The team believes that the Neanderthal variants may sensitize the sensory neurons by changing the threshold at which a nerve impulse is generated. The variants could also be more common in populations with higher proportions of Native American ancestry due to random chance as well as population bottlenecks that occurred during when the Americas were first colonized by Europeans

“Although Neanderthal intermixing with Europeans is now well-known in popular culture, their genetic contribution to other human groups, such as Native Americans in this case, is less talked about,” study co-author and population geneticist at the National Research Institute for Agriculture, Food and the Environment in France Pierre Faux tells PopSci. “In this study, we saw how important and relevant it is to study genetic backgrounds that are under-represented in medical cohorts.”

Since acute pain can play a role in moderating behavior and preventing further injury, the team is planning additional research to determine if carrying these variants and having greater sensitivity to pain was advantageous during human evolution. Understanding how these variants work could also help physicians understand and treat chronic pain.

“Genes are just one of many factors, including environment, past experience, and psychological factors, which influence pain,” says Bennet. 

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New neon-yellow snail from the Florida Keys gets a happy hour-ready name https://www.popsci.com/environment/margarita-snail/ Tue, 10 Oct 2023 14:00:00 +0000 https://www.popsci.com/?p=578159
An underwater closeup of Cayo margarita (a new species) in the coral reef of the Florida Keys. Note the two long tentacles, used by the snail to spread the mucus net for feeding.
An underwater closeup of Cayo margarita (a new species) in the coral reef of the Florida Keys. Note the two long tentacles, used by the snail to spread the mucus net for feeding. Rüdiger Bieler

Wastin’ away again with a margarita snail.

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An underwater closeup of Cayo margarita (a new species) in the coral reef of the Florida Keys. Note the two long tentacles, used by the snail to spread the mucus net for feeding.
An underwater closeup of Cayo margarita (a new species) in the coral reef of the Florida Keys. Note the two long tentacles, used by the snail to spread the mucus net for feeding. Rüdiger Bieler

A new marine snail that would make the late great Jimmy Buffet proud has been discovered in the Florida Keys. The lemon-colored snail is named Cayo margarita after the Spanish word for “small, low island” and the tropical drink Buffet sings about in one of his biggest hits. The new and real resident of the fictional Margaritaville is described in a study published October 9 in the journal PeerJ.

[Related: This cone snail’s deadly venom could hold the key to better pain meds.]

Marine smells are distantly related to the land-dwelling gastropods in gardens around the world. The margarita snails come from a group nicknamed worm snails, since they spend many of their lives living in one place. Worm snails also do not have a protective covering found in other snails called an operculum. This body part allows the snails to retreat further inside their shell and keep their bodies moist.

“Worm snails are just so different from pretty much any other regular snail,” study co-author Rüdiger Bieler tells PopSci. “These guys are sitting in the middle of the coral reef where everybody is out trying to eat them. And they’ve given up that protection and just advertise with their bright colors.”

Bieler is a marine biologist and curator of invertebrates at the Field Museum in Chicago who has spent 40 years studying the Western Atlantic’s invertebrates. Even after decades studying the region, these worm snails were hiding in plain sight during dive trips, largely because these snails are kind of the ultimate introverts.

Look closely. A margarita snail in the middle of a dead section of a large brain coral. CREDIT: R. Bieler.
Look closely. A margarita snail in the middle of a dead section of a large brain coral. CREDIT: R. Bieler.

Once juvenile worm snails find a spot to hunker down and they cement their shell to a hard surface never really move again. “Their shell continues to grow as an irregular tube around the snail’s body, and the animal hunts by laying out a mucus web to trap plankton and bits of detritus,” Bieler explains

Bieler and the rest of the international team of researchers came across the lemon-yellow snails in the Florida Keys National Marine Sanctuary and a similar lime-colored snail in Belize. Within the same species of snails, it is possible to get many different colors. There can also be color variations in a single population or even cluster of snails. Bieler believes that they may do this to confuse some of the coral reef fish that can see color so that they do not have a clear target. Some may use their hue as a warning color.  

The team initially believed that the lime-green and lemon-yellow snails were different species, but DNA sequencing revealed just how unique they are. This new yellow species belongs to the same family of marine snails as the invasive snail nicknamed the “Spider-Man” snail. This same team found these snails in 2017 on the Vandenberg shipwreck off the Florida Keys.

[Related: Invasive snails are chomping through Florida, and no one can stop them.]

The snails in this new Cayo genus also share a key trait in common with another worm snail genus called Thylacodes. The species Thylacodes bermudensis is found near Bermuda, and while only distantly related to their Floridaian and Belizean cousins, they have small colored heads and mucus that pop out of tubular shells. This might work as a deterrent to keep corals, anemones, and other reef fish from getting too close. The mucus has some nasty metabolites in it which might explain why these snails risk exposing their heads. 

The study and the new snails described in it help illuminate the stunning biodiversity of the world’s coral reefs, which are under serious threat due to climate change and the record warm ocean temperatures this summer

“These little snails are kind of beacons for biodiversity that need to be protected because many of them are dying out before we even get a chance to study them,” says Biler. 

It is also an important lesson in always looking right under your nose for discovery.

“I’ve been doing this for decades. We still find new species and previously unknown morphologies right under our feet,” says Biler. “This [discovery] was at snorkeling depth and in one of the most heavily touristed areas in the United States. When you look closely, there are still new things.”

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4 capybara facts you’ll love, and 1 you’d like to forget https://www.popsci.com/environment/capybara-facts/ Mon, 09 Oct 2023 22:00:00 +0000 https://www.popsci.com/?p=577276
A capybara standing on a riverbank. Capybaras are semi-aquatic rodents that can weigh up to 174 pounds.
Capybaras are semi-aquatic rodents that can weigh up to 174 pounds. Deposit Photos

It's the cabybara's world, we're just living in it.

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A capybara standing on a riverbank. Capybaras are semi-aquatic rodents that can weigh up to 174 pounds.
Capybaras are semi-aquatic rodents that can weigh up to 174 pounds. Deposit Photos

The internet has recently fallen in love with South America’s charismatic rodents called Capybaras. From catchy songs to memes, it’s hard not to see the chunky charmers in your feed these days. Here are some fun facts about these captivating creatures to inform your scrolling.

[Related: Capybara spent a month on the lam after escape from Toronto Zoo.]

Where can I see a capybara in the wild?

Capybaras are the largest rodent in the world can be found east of the Andes Mountains and the riverbanks in Central and South America from Panama to Argentina. Since they are semi-aquatic like beavers and hippos, capybaras typically live beside ponds, swamps, marshes, or wherever standing water is available. They are also called “water hogs” or “capys” and can even stay under water for more than five minutes to escape from predators like anacondas and jaguars. 

They have been known to encroach further into human territory as their habitat is dwindling. Since 2020, hundreds of capybaras have taken over Nordelta, a private and gated neighborhood outside of Buenos Aires. The rodents had always been around, but remained hidden. The lockdowns triggered by the COVID-19 pandemic enabled the furry capys to spread and flourish in the posh neighborhood’s parks. 

Multiple zoos in the United States, including the Cincinnati Zoo and Botanical Garden (also home to some famous hippos), Southwick’s Zoo in Massachusetts, and the Cape May County Park and Zoo in New Jersey, are home to a handful of adorable specimens as well. 

CREDIT: Cincinnati Zoo and Botanical Garden.

Do capybaras really eat their own poop?

Yes, among other things. They eat their poop for beneficial bacteria that helps their stomach break down the thick fiber from their other food sources such as reeds and grains, according to the San Diego Zoo

Like other rodents, capybaras have ever-growing front teeth. They use their sharp and long chompers to graze on grass and water plants. When fresh grasses and water plants dry up during the dry season, they eat squashes, melons, reeds, and grains. An adult can eat about six to eight pounds of grasses per day. 

How big are capys?

There are two known species of capybara: Hydrochoerus hydrochaeris and Hydrochoerus isthmius.  Of the two, H.hydrochaeris is the largest living rodent in the world. It can grow up to 4.3 feet long and weigh a whopping 174 pounds. H. isthmius is a bit smaller. It can grow to about 3 feet long and weigh closer to 62 pounds.

[Related: These prehistoric rodents were social butterflies.]

Can I own a capybara as a pet in the United States?

It depends what state you call home. They are currently legal with restrictions in some states including Texas, Pennsylvania, Nevada, Arizona, and Georgia. California and New York have more stringent rules, including that the animals can only be obtained by those with an approved scientific or educational reason. While ownership may be legal at the state, it may be illegal at the city level. 

Yahoo Finance estimates that the initial cost to buy a capy on the exotic animal market is about $1,000 per animal, while other estimates place the cost at $8,000. Vet bills can easily stretch between $600 to $1,000 each year?? and owners need to keep in mind the six to eight pounds of food that they can eat per day. Capybaras are also social animals, so owners need to be prepared to take in more than one for their pet to thrive. 

What are capys all over my feed?

Basically, capybaras are kind of the new Baby Shark. The song Capybara from Russian artist Сто-Личный Она-Нас went viral on TikTok earlier this year. Listen at your own risk, as it is a textbook earworm that will be stuck in your head for days.

Popular videos include a capybara sparring with a platypus and jumping into above ground pools. They are also the stars of pop culture memes, including one celebrating the billion dollar hit movie Barbie. 

A meme that reads "this Barbie is pulling up," with a photo of a capybara and the Barbie logo.
CREDIT: Capyverse via Instragram

They are also known for being some of the friendliest critters in the animal kingdom. They are very social and live together in herds of 10 to 20 animals. They spend time together cuddling, playing, socializing, and grooming one another. They have even been known to try to use alligators to hitch a ride

It also doesn’t hurt that they are really cute. In an era of doom scrolling, sometimes it’s just nice to look at their hippo-like eyes and ears as they look above the water. 

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A newly discovered sauropod dinosaur left behind some epic footprints https://www.popsci.com/science/garumbatitan-morellensis-dinosaur/ Fri, 06 Oct 2023 15:00:00 +0000 https://www.popsci.com/?p=577496
Evolution photo

Garumbatitan morellensis' vertebrae alone were nearly 3 feet wide.

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Evolution photo

Meet Garumbatitan morellensis, a new species of large sauropod dinosaur. The Giganotosaurus relative called the present-day Iberian Peninsula home about 122 million years ago. The remains of this titan were discovered in Morella, Spain, and this discovery could help fill in some major evolutionary gaps. The findings were described in a study published September 28 in the journal Zoological Journal of the Linnean Society.

[Related: Cushy feet supported sauropods’ gigantic bodies.]

G. morellensis belongs to the sauropod group of dinosaurs, which includes some well-known favorites like Diplodocus and Brachiosaurus. Sauropods were four-legged Early Jurassic and Cretaceous Era dinos known for their long necks that could reach up to 49 feet long in some species and lengthy tails. G. morellensis is also a member of a subgroup of sauropods known as titanosaurs. These giants were the largest of an already big group and titanosaurs survived right up until the asteroid that wiped out the dinosaurs struck about 66 million years ago.

This new dinosaur’s remains were found and excavated in the Sant Antoni de la Vespa fossil-site in 2005 and 2008. This fossil deposit is home to one of the largest concentrations of sauropod dinosaur remains that date back to the Lower Cretaceous period in Europe (about 145 million to 66 million years ago). Scientists found the remains of a giant unidentified sauropod in Portugal in 2022 that could be Europe’s oldest known dinosaur fossil at 150 million-years-old. 

The team of paleontologists from Portugal and Spain found the remains of three G. morellensis individuals and one other sauropod. Their lucky find included a rare set of footprints. They also uncovered giant vertebrae, leg bones, and two near-complete sets of foot bones. 

An artist’s reconstruction of the life appearance of Garumbatitan morellensis. The dinosaur is green with a very long neck and tail, and stands near a waterhole.
An artist’s reconstruction of the life appearance of Garumbatitan morellensis. Grup Guix

“One of the individuals we found stands out for its large size, with vertebrae more than one meter wide [3.2 feet], and a femur that could reach two meters [6.5 feet] in length. We found two almost complete and articulated feet in this deposit, which is particularly rare in the geological record,” study co-author and University of Lisbon paleontologist Pedro Mocho said in a statement

G. morellensis was probably close to an average-size titanosaur and could have been near 94 feet long. Its leg shape and foot bones suggest that it was one of the more primitive sauropods from a subgroup called Somphospondyli, according to the authors. Somphospondylan fossils have been found on every present-day continent, but paleontologists are not sure where they originated. This discovery of such an early specimen in Spain points to Europe as a possible origin point for this subgroup, but more evidence is needed.  

[Related: Europe’s largest dinosaur skeleton may have been hiding in a Portuguese backyard.]

This discovery also highlights how complex the evolutionary history of sauropods in the Iberian Peninsula and the rest of Europe is. Species related to these lineages have been found in Asia, North America, and possibly Africa. This points to a potentially long period of dinosaur dispersal within continents and this fossil deposit might fill in some major gaps of evolutionary history. 

“The future restoration of all fossil materials found in this deposit will add important information to understand the initial evolution of this group of sauropods that dominated dinosaur faunas during the last million years of the Mesozoic era,” study co-author and Universidad Nacional de Educación a Distancia in Madrid paleontologist Francisco Ortega said in a statement.

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Do the ancient human footprints at White Sands date back to the last ice age? https://www.popsci.com/science/white-sands-human-footprints-new-analysis/ Thu, 05 Oct 2023 19:30:00 +0000 https://www.popsci.com/?p=577342
White Sands NPS staff excavating fossilized human footprints from lakebed
The oldest human footprints found in White Sands National Park were initially excavated in 2009. NPS

New tests on the millennia-old footprints confirm their age. But debate around the first humans to live in the Americas will continue.

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White Sands NPS staff excavating fossilized human footprints from lakebed
The oldest human footprints found in White Sands National Park were initially excavated in 2009. NPS

In 2006, a cluster of mysterious dark spots on a lakebed of White Sands National Park in New Mexico caught the attention of archaeologists. The shapes stroked their curiosity until they eventually excavated the site three years later. Waiting for them was one of the rarest and soon-to-be controversial discoveries in history—a set of fossilized human footprints

The preserved markings were found on the shore of a lake that existed during the most recent ice age, and could be one of the earliest signs of biped migration to North America. Some experts claim they are the steps of the Clovis people, the continent’s first human inhabitants and the ancestors for most Native Americans. The Clovis are thought to have made the journey to North America 13,000 to 13,500 years ago using a land bridge that connected Asia to Alaska. From there, they continued to move as far down south as Central and South America. 

Archaeologists speculate there was a short window of time when our species could have crossed over the land bridge because sea levels dropped low enough to expose it. A scientific simulation last December found the land bridge appeared 35,700 years ago near the end of the last ice age (or the last Glacial Maximum). The likelihood of Homo sapiens appearing in North America before then was unthinkable: The frozen terrain would have made it impossible for them to hunt, and any food supplies they packed would have eventually run out. 

The White Sands footprints walk us through a different origin story. A 2021 study had dated them to 21,000 to 23,000 years ago, and in a new report published today in the journal Science, the same team of experts confirmed the hotly debated estimates with two new tests. Not only does this mean humans were here during the last ice age, but it also could change what we know about the first people that came to North America.

“This was groundbreaking to the archaeologic community, and it was also a tough pill to swallow,” says Kathleen Springer, a research geologist for the United States Geological Survey (USGS) who helped analyze the fossilized steps. “Having 23- to 21,000-year-old footprints is much earlier than the prevailing paradigm of Clovis or pre-Clovis that are known in this part of North America.”

Ancient human footprint at White Sands National Park
One of the footprints in question at White Sands National Park. USGS

The finding initially received some pushback. When the results were first revealed in 2021, concerned archaeologists wrote comments and papers challenging the results, citing the need for better evidence. More specifically, they criticized the study method and the decision to use radiocarbon dating on the seeds of an aquatic plant that was excavated from the same site. 

Part of the debate came down to an isotope that’s often used in archaeological work. Carbon-14 forms in the air and is introduced to photosynthetic plants and the animals that eat them. When flora and fauna are alive, they have the same amount of carbon-14 as the Earth’s atmosphere; when they die, it decays in their remains. Scientists can then measure how much of the isotope is left and use that metric to calculate an organism’s approximate age. But as some experts have pointed out, aquatic plants like the ones sampled at White Sands can get carbon from the water they live in, which can skew the measurements and make a specimen seem older than it really is.

“It’s called the hard water effect, and it’s a really well-known problem with radiocarbon dating,” explains Jeffrey Pigati, a USGS research geologist who co-authored both studies with Springer. He says the general argument with the first paper is that there were large hard-water effects that made them overestimate the age of the footsteps when they should have been around 15,000 or 17,000 years old.

The COVID pandemic delayed many of the follow-up experiments Pigati and Springer wanted to complete when investigating the site in 2020. Three years later, they finally did with two new methods that corroborate their original estimate of the footprints’ age: radiocarbon dating of pollen and luminescence dating.

Researchers digging in the lakebed with the White Sands human footprint archaeological site
Researchers from the US Geological Survey and National Park Service sampled pollen grains and quartz crystals from trenches in the White Sands lakebed. USGS

To avoid heavy-water effects, the team extracted pollen grains from the same sediment as the White Sands footprints. According to Pigati, this is a time-consuming and laborious process because it involves breaking down rock into one cubic centimeter of material and separating pollen from other organic material before measuring carbon-14 levels. Additionally, pollen is extremely light—experts need to sample thousands of grains to meet the minimum mass requirement for a single radiocarbon measurement. In total, they successfully isolated 75,000 pollen grains. When the they compared the measurements to ones from the seeds of the aquatic plant, the ages matched.

The second technique was optically stimulated luminescence (OSL) dating. Unlike radiocarbon dating, OSL dating is based on the buildup of luminescence properties in quartz crystals over time; in some rare cases, it can date sediments as far back as 400,000 years ago. The USGS team dated three different mineral samples from the same area where the footprint was discovered and calculated ages that were similar to the ones measured in the seeds.

“Because of how paradigm shifting this result is, it needed to be ironclad and that was the motivation all along to provide multiple lines of evidence,” says Springer. When asked about Indigenous representation on the recent analysis, she notes that it involved 32 Native American tribes and pueblos and two archaeologists, Edward Jolie from the University of Arizona and Joe Watkins of the National Park Service.

The additional data appears to have quelled many of the concerns initially raised by scientists. In a Science commentary also published today, Bente Philippsen, an archaeologist at the Norwegian University of Science and Technology, says the newly presented data “strongly indicate human presence in the Americas around the [Last Glacial maximum].”

Still, this does not mean we have a complete picture of our species’ migration to North America. Paulette Steeves, an archaeologist and author of The Indigenous Paleolithic of the Western Hemisphere, who was not involved in the White Sands research, says there are archaeological sites in both North and South America that date to as early as 11,000 to 200,000 years ago. While she argues it’s not the oldest sign of human habitation in the Americas and may not be proof of the first Indigenous group, “the White Sands footprints site is a great addition to the record of early people in the Western Hemisphere.”

The footprints are just one piece of the puzzle. Archaeologists still don’t know exactly how people lived in the middle of an ice age and weathered harsh climate. Future projects at White Sands could include tracking the footprints to a campsite or further scouring the area for stone tools that could give some insight into their survival. “Every day we’re working out there is amazing because you never know what is going to be discovered,” Pigati says. “This is all a part of science in action.”

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A new noninvasive patch could monitor a vital hormone https://www.popsci.com/technology/sweat-sensor-hormones/ Thu, 05 Oct 2023 19:00:00 +0000 https://www.popsci.com/?p=577281
Sweat sensor worn like a ring on finger
The thin sensor measures estradiol, the most potent form of estrogen. Caltech

Estradiol is usually only measured via blood and urine samples, but this new patch only needs a little sweat.

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Sweat sensor worn like a ring on finger
The thin sensor measures estradiol, the most potent form of estrogen. Caltech

Wearable sensors can already monitor a variety of important health characteristics. But they are still far short when it comes to detecting hormonal levels, particularly for women. A new device designed by researchers at Caltech, however, is specifically tailored to measure one of women’s most vital and influential hormones. According to the team’s study, recently published in Nature Nanotechnology, their new wearable sensor can detect and assess users’ estradiol levels by just analyzing sweat droplets.

Estradiol, the most potent form of estrogen, is a crucial component in women’s health. Not only is it necessary in regulating reproductive cycles and ovulation, but this hormone’s levels are directly correlated to issues ranging from depression, to osteoporosis, to even heart disease. Currently, estradiol monitoring requires blood or urine samples collected either in-clinic or at-home. In contrast, Caltech’s new sensor, created by assistant professor of medical engineering Wei Gao, only needs miniscule amounts of sweat collected via extremely small automatic valves within its microfluidic system.

[Related: This organ-failure detector is thinner than a human hair.]

The sensor’s reliance on sweat to measure estradiol isn’t only impressive due to its non-invasive nature; according to Caltech’s announcement, the hormone is about 50 times less concentrated in sweat than in blood.

The wearable’s monitoring system utilizes aptamers—short, single-strand DNA capable of binding to target molecules like artificial antibodies. Gao’s team first attached aptamers to a surface imbued with inkjet-printed gold nanoparticles. The aptamers then could bind with targeted molecules—in this case, estradiol. Once connected, the molecule gets recaptured by other titanium carbide-coated gold nanoparticles known as “MXenes.” The resultant electrical signal can be wirelessly measured and correlated to estradiol levels via a simple-to-use smartphone app.

To actually collect the sweat samples, the sensor uses tiny channels controlled by automatic valves to allow only fixed amounts of fluid into the sensor. To take patients’ sweat composition differences into consideration, the device also consistently calibrates via information collected on salt levels, skin temperature, and sweat pH.

This isn’t Gao’s first sweat sensor, either—previous variants also could detect the stress hormone cortisol, COVID-19, as well as a biomarker that indicates inflammation.

“People often ask[ed] me if I could make the same kind of sweat sensor for female hormones, because we know how much those hormones impact women’s health,” Gao said via Caltech’s announcement. With further optimization, the new estradiol sensor could help users attempting to naturally or in vitro conceive children, as well as aid those necessitating hormone replacement therapies. According to Gao, the team also intends to expand the range of female hormones they can detect, including another ovulation-related variant, progesterone.

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An ‘electronic tongue’ could help robots taste food like humans https://www.popsci.com/technology/electronic-tongue-ai-robot/ Wed, 04 Oct 2023 20:00:00 +0000 https://www.popsci.com/?p=577156
Electronic artificial tongue sensor
The sensor could one day help AI develop their own versions of taste palates. Das Research Lab/Penn State

A combination of ultra-thin sensors marks the first step in machines being able to mimic our tastes.

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Electronic artificial tongue sensor
The sensor could one day help AI develop their own versions of taste palates. Das Research Lab/Penn State

AI programs can already respond to sensory stimulations like touch, sight, smell, and sound—so why not taste? Engineering researchers at Penn State hope to one day accomplish just that, in the process designing an “electronic tongue” capable of detecting gas and chemical molecules with components that are only a few atoms thick. Although not capable of “craving” a late-night snack just yet, the team is hopeful their new design could one day pair with robots to help create AI-influenced diets, curate restaurant menus, and even train people to broaden their own palates.

Unfortunately, human eating habits aren’t based solely on what we nutritionally require; they are also determined by flavor preferences. This comes in handy when our taste buds tell our brains to avoid foul-tasting, potentially poisonous foods, but it also is the reason you sometimes can’t stop yourself from grabbing that extra donut or slice of cake. This push-and-pull requires a certain amount of psychological cognition and development—something robots currently lack.

[Related: A new artificial skin could be more sensitive than the real thing]

“Human behavior is easy to observe but difficult to measure. and that makes it difficult to replicate in a robot and make it emotionally intelligent. There is no real way right now to do that,” 

Saptarshi Das, an associate professor of engineering science and mechanics, said in an October 4 statement. Das is a corresponding author of the team’s findings, which were published last month in the journal Nature Communications, and helped design the robotic system capable of “tasting” molecules.

To create their flat, square “electronic gustatory complex,” the team combined chemitransistors—graphene-based sensors that detect gas and chemical molecules—with molybdenum disulfide memtransistors capable of simulating neurons. The two components worked in tandem, capitalizing on their respective strengths to simulate the ability to “taste” molecular inputs.

“Graphene is an excellent chemical sensor, [but] it is not great for circuitry and logic, which is needed to mimic the brain circuit,” said Andrew Pannone, an engineering science and mechanics grad student and study co-author, in a press release this week. “For that reason, we used molybdenum disulfide… By combining these nanomaterials, we have taken the strengths from each of them to create the circuit that mimics the gustatory system.”

When analyzing salt, for example, the electronic tongue detected the presence of sodium ions, thereby “tasting” the sodium chloride input. The design is reportedly flexible enough to apply to all five major taste profiles: salty, sour, bitter, sweet, and umami. Hypothetically, researchers could arrange similar graphene device arrays that mirror the approximately 10,000 different taste receptors located on a human tongue.

[Related: How to enhance your senses of smell and taste]

“The example I think of is people who train their tongue and become a wine taster. Perhaps in the future we can have an AI system that you can train to be an even better wine taster,” Das said in the statement.

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Mammals may use same-sex sexual behavior for conflict resolution, bonding, and more https://www.popsci.com/environment/mammals-same-sex-behavior-evolution/ Wed, 04 Oct 2023 16:45:00 +0000 https://www.popsci.com/?p=577090
Two chimpanzees share a meal. A new study found that same-sex sexual behavior helps establish and maintain positive social relationships in animals including chimpanzees, bighorn sheep, lions, and wolves.
A new study found that same-sex sexual behavior helps establish and maintain positive social relationships in animals including chimpanzees, bighorn sheep, lions, and wolves. Deposit Photos

It's been observed in at least 51 species of non-human primates.

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Two chimpanzees share a meal. A new study found that same-sex sexual behavior helps establish and maintain positive social relationships in animals including chimpanzees, bighorn sheep, lions, and wolves.
A new study found that same-sex sexual behavior helps establish and maintain positive social relationships in animals including chimpanzees, bighorn sheep, lions, and wolves. Deposit Photos

Over 1,500 animal species, from bonobos to sea urchins to penguins are known to engage same-sex sexual behavior. Still, scientists don’t understand exactly how it came to be or why it happens. While some say the behavior might have existed since the animal kingdom first arose more than half a billion years ago, it may have actually evolved repeatedly in mammals. A study published October 3 in the journal Nature Communications suggests that the behavior possibly plays an adaptive role in social bonding and reducing conflict, and evolved multiple times.

[Related: A massive study confirms no one ‘gay gene’ controls sexual preference.]

The behavior is particularly prevalent in nonhuman primates. It has been observed in at least 51 species from small lemurs up to bigger apes. For one population of male macaques, same-sex sexual behavior may even be a common feature of reproduction and is related to establishing dominance within groups, handling a shortage of different-sex partners, or even reducing tension following aggressive behavior. 

In this new study, the team from institutions in Spain surveyed the available scientific literature to create a database of records of same-sex sexual behavior in mammals. They traced the behavior’s evolution across mammals and tested for any evolutionary relationships with other behaviors. 

The team found that same-sex sexual behavior is widespread across mammal species, occurs in similar frequency in both males and females, and likely has multiple independent origin points. This analysis found that the behavior helps establish and maintain positive social relationships in animals including chimpanzees, bighorn sheep, lions, and wolves.

“It may contribute to establishing and maintaining positive social relationships,” study co-author José Gómez told The New York Times. “With the current data available, it seems that it has evolved multiple times.” Gómez is an evolutionary biologist at the Experimental Station of Arid Zones in Almería, Spain. 

Importantly, they caution that the study should not be used to explain the evolution of sexual orientation in humans. This research focused on same-sex sexual behavior defined as short-term courtship or mating interactions, instead of a more permanent sexual preference. 

Additionally, male same-sex sexual behavior was likely evolved in species with high rates of male adulticide–-when adult animals kill other adults. The team believes that this suggests the behavior may be an adaptation meant to mitigate the risks of violent conflict between males.

Harvard University primatologist Christine Webb, who did not participate in the study, told The Washington Post that the findings add to other research and widen the scope of what it means for a behavior to be considered adaptive.

[Related: Same-sex mounting in male macaques can help them reproduce more successfully.]

“This general question of evolutionary function—that behavior must aid in survival and reproduction—what this paper is arguing is that reaffirming social bonds, resolving conflicts, managing social tensions, to the extent that same-sex sexual behavior preserves those functions—it’s also adaptive,” Webb said. 

Webb also added that it makes sense that other animals would have sex for a variety of reasons the way that humans do.

The authors caution that these associations could also be driven by other evolutionary factors. Same-sex sexual behavior has also only been carefully studied in a minority of mammal species, so our understanding of the evolution of same-sex sexual behavior may continue to change as more mammalian species are studied.

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How we can help the most endangered class of animals survive climate change https://www.popsci.com/environment/amphibians-climate-change-conservation/ Wed, 04 Oct 2023 15:00:00 +0000 https://www.popsci.com/?p=577023
The Morona-Santiago stubfoot toad (Atelopus halihelos) in Ecuador is listed as critically endangered.
The Morona-Santiago stubfoot toad (Atelopus halihelos) in Ecuador is listed as critically endangered. Jaime Culebras/Photo Wildlife Tours

Two out of five amphibians are currently threatened with extinction.

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The Morona-Santiago stubfoot toad (Atelopus halihelos) in Ecuador is listed as critically endangered.
The Morona-Santiago stubfoot toad (Atelopus halihelos) in Ecuador is listed as critically endangered. Jaime Culebras/Photo Wildlife Tours

Earth’s amphibians are in serious trouble, but there is still time to save this unique class of animals. A study published October 4 in the journal Nature finds that two out of five amphibians are threatened with extinction and they continue to be the most threatened class of vertebrates. However, the new research also found that since 1980, the extinction risk of 63 species has been reduced due to conservation interventions.

[Related: Why you can’t put a price on biodiversity.]

“This proves that conservation works and it’s not all bad news,” Jennifer Luedtke, a study co-author and the manager of IUCN Red List Assessments at conservation organization Re:wild, said during a press conference. “We found that habitat protection alone is not sufficient. We need to mitigate the threats of disease and climate change.”

A check-up for amphibians

The findings are part of Global Amphibian Assessment II, an international series of conservation analyses based on evaluations of the 8,011 amphibian species listed on the IUCN Red List. The first Global Amphibian Assessment was published in 2004 and found that amphibians are Earth’s most threatened class of vertebrates. This second report confirms that the smooth-skinned animals are still more threatened than birds or mammals.

In the study, the team found that 118 species have been driven to extinction between 2004 and 2022. About 40 percent of the species studied are still categorized as threatened. This study also covers about 94 percent of the known amphibian species in 2022. According to Luedtke, about 155 new amphibian species are discovered every year, so there will likely be more species to add to the next Global Amphibian Assessment. 

Climate change and associated habitat loss are the primary driver of these declines. The team estimates that current and projected climate change effects are responsible for 39 percent of status deteriorations since 2004. Habitat loss has affected roughly 37 percent of species in the same period. 

Why amphibians are so vulnerable to climate change

Amphibians’ unique skin puts them in more danger in the face of a changing planet, since they use their skin to breathe. Increased frequency and intensity of storms, floods, droughts, changes in moisture levels and temperature, and sea level rise can all affect their very important breathing sites.

“They don’t have any protection in their skin like feathers, hair, or scales. They have a high tendency to lose water and heat through their skin,” Patricia Burrowes, a study co-author and herpetologist formerly with the University of Puerto Rico, said during a press conference. “The majority of frogs are nocturnal, and if it’s very hot, they will not come out because they will have lost so much water even in their retreat sites that they don’t have the energy to go out to feed. They won’t grow and won’t have energy to reproduce. And that can have demographic impacts.”

[Related: Hellbender salamanders may look scary, but the real fright is extinction.]

Extinctions have continued to increase with 37 documented in 2022. By comparison 23 species were reported extinct by 1980 and 33 in 2004. According to the report, the most recent species to go extinct were the frogs Atelopus chiriquiensis from Costa Rica and western Panama and Taudactylus acutirostris from Australia.

“Amphibians are essential parts of the ecosystem in a variety of ways, one of them being their role in the food web,” Kelsey Neam, study co-author and Re:wild’s Species Priorities and Metrics Coordinator, said during a press conference. “Amphibians are prey for many species and without amphibians, those animals lose a major source of their food and they are preying upon other animals like insects and other invertebrates. Without them to fulfill that niche, we will see a collapse of the food web.”

Amphibian pandemics

The most heavily affected amphibians were salamanders and newts, with three out of five salamander species at risk for extinction. While habitat loss is also the primary threat to salamanders, they are also particularly vulnerable to a disease called chytridiomycosis. It is caused by a fungal pathogen caused by the chytrid fungus that disrupts amphibian’s skin and physiological functions. When infected, amphibians can’t rehydrate properly, which creates an electrolyte imbalance that causes fatal heart attacks.

The Hickory Nut Gorge green salamander (Aneides caryaensis) is found in North Carolina, and is listed as critically endangered.
The Hickory Nut Gorge green salamander (Aneides caryaensis) is found in North Carolina, and is listed as critically endangered. CREDIT: Todd W. Pierson

“Droughts exacerbate the infection intensity,” said Burrowes. “When the frogs have the potential to present some kind of defense mechanism, that defense mechanism is monitored by changes in precipitation and temperature.”

North America is home to the world’s most biodiverse community of salamanders, including a group of lungless salamanders in the Appalachian Mountains. This has conservationists concerned about what would happen if another deadly fungal disease called Batrachochytrium salamandrivorans, or B.sal, arrives in the Americas from Asia or Europe.

‘We know what to do’

The report highlights that the time to help these critical animals is now. The authors point to the Kunming-Montreal Global Biodiversity Framework adopted by 190+ signatory countries at the United Nations Biodiversity Conference in December 2022. The signing nations committed to halting all human induced extinctions, reversing and reducing the extinction risk of species tenfold, and to recovering populations to a healthy level.

“We know what to do. It’s time to really commit the resources to actually achieving the change that we say we want,” said Luedtke. “Amphibians will be the better for it and so will we.”

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No two parakeets sound exactly the same https://www.popsci.com/environment/parakeet-voice-print/ Tue, 03 Oct 2023 23:15:00 +0000 https://www.popsci.com/?p=576816
A green monk parakeet standing in dirt. Parrots could have a unique tone of voice just like humans do.
Monk parakeets could have a unique tone of voice just like humans do. Deposit Photos

The unique 'voice prints' could help the chatty birds pick one another out in a flock, according to new research.

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A green monk parakeet standing in dirt. Parrots could have a unique tone of voice just like humans do.
Monk parakeets could have a unique tone of voice just like humans do. Deposit Photos

Parrots are the chatterboxes of the animal kingdom. These famously social birds can learn new sounds throughout their lives and even produce calls that can be individually recognized by other members of their flock. A new study of monk parakeets found that individual birds have a unique tone of voice similar to humans called a “voice print.” The findings are described in a study published October 3 in the journal Royal Society Open Science.

[Related: The next frontier in saving the world’s heaviest parrots: genome sequencing.]

“It makes sense for monk parakeets to have an underlying voice print,” Simeon Smeele, a co-author of the study and biologist studying parrot social and vocal complexity at the Max Planck Institute of Animal Behavior, said in a statement. “It’s an elegant solution for a bird that dynamically changes its calls but still needs to be known in a very noisy flock.”

In humans, our voice print leaves a unique signature in the tone of our voice across every word we say. These voice prints remain even though humans have a very complex and flexible vocal repertoire. Other social animals also use similar cues to recognize one another. Individual dolphins, bats, and birds have a “signature call” that makes them identifiable to other members of their groups. However, signature calls encode identity in only one call type, and there hasn’t been much evidence that suggests animals have unique signatures that last throughout their entire repertoire of calls. 

Parrots use their tongue and mouth to modulate calls similar to the way humans speak. According to Smeele, “their grunts and shrieks sound much more human than a songbird’s clean whistle.” 

Parrots also live in large groups with fluid membership where multiple birds vocalize at the same time. Members need a way to keep track of which individual is making what sound. The question became if the right physical anatomy coupled with the need to navigate complex social lives, helped parrots evolve a voice print. 

In the study, Smeele and his team traveled to Barcelona, Spain—home to the largest population of individually marked parrots in the wild. The parakeets are considered an invasive species and they swarm Barcelona’s parks in flocks with hundreds of members. The Museu de Ciències Naturals de Barcelona has been marking the parakeets for 20 years and have individually identified 3,000 birds.

The team used microphones to record the calls of hundreds of individuals and collected over 5,000 vocalizations in total. They also re-recorded the same individuals over a period of two years, which revealed the stability of the calls over time.

Using a set of computer models, they detected how recognizable individual birds were within each of the five main call types given by this species (contact, tja, trrup, alarm, and growl). They found high variability in the “contact call” that birds use to broadcast their identity. According to the team, this overturned a long-held assumption that contact calls contain a stable individual signal. The new findings suggested that the parakeets are actually using something else for individual recognition.

[Related: These clever cockatoos carry around toolkits to get to food faster.]

To investigate if voice prints were at play, the team used a machine learning model widely used in human voice recognition. The model detects the identity of the speaker using the quality, or timbre, of their voice. The team trained the model to recognize calls of individual birds that were categorized as “tonal” in sound. They then tested to see if the model could detect the same individual from a separate set of calls that were classified as “growling” in sound. The model was able to identify the individual parrots three times better than expected, providing evidence that monk parakeets do actually have a recognizable, individual voice print. 

While exciting, the authors caution that this evidence is still preliminary. Future experiments and analyses could use the parrot tagging work from the team in Barcelona. The GPS devices could help determine how much individuals overlap in their roaming areas.

“This can provide insight into the species’ remarkable ability to discriminate between calls from different individuals,” study co-author and ecologist from Museu de Ciències Naturals de Barcelona Juan Carlos Senar said in a statement.

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4 reasons dinosaurs never really ruled the Earth https://www.popsci.com/science/age-of-the-dinosaurs-facts/ Tue, 03 Oct 2023 17:00:00 +0000 https://www.popsci.com/?p=576210
T. rex model, T. rex skull, and Triceratops skull at dinosaur display in the Museum of Natural History in Vienna
(Clockwise from top) A T. rex model, T. rex skull, and Triceratops skull on display at the Museum of Natural History in Vienna, Austria. DepositPhotos

The 'terrible lizards' can reign supreme in the movies, but there's something seriously wrong about the way we've hyped up their history.

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T. rex model, T. rex skull, and Triceratops skull at dinosaur display in the Museum of Natural History in Vienna
(Clockwise from top) A T. rex model, T. rex skull, and Triceratops skull on display at the Museum of Natural History in Vienna, Austria. DepositPhotos

We all know the line: For more than 150 million years, dinosaurs ruled the Earth. We imagine bloodthirsty tyrannosaurs ripping into screaming duckbills, gigantic sauropods shaking the ground with their thunderous footfalls, and spiky stegosaurs swinging their tails in a reign of reptiles so magnificent, it took the unexpected strike of a six-mile-wide asteroid to end it. The ensuing catastrophe handed the world to the mammals, our ancestors and relatives, so that 66 million years later we can claim to have taken over what the terrible lizards left behind. It’s a dramatic retelling of history that is fundamentally wrong on several counts. Let’s talk about some of the worst rumors and what really happened in the so-called “Age of Dinosaurs.”

Myth: Dinosaurs dominated the planet from their origin.

Fact: Dinosaurs started as cute pipsqueaks.

The oldest dinosaurs we know about are around 235 million years old, from the middle part of the Triassic Period. Those reptiles didn’t rule anything. From recent finds in Africa, South America, and Europe, we know that they were no bigger than a medium-sized dog and were lanky, omnivorous creatures that munched on leaves and beetles. Ancient relatives of crocodiles, by contrast, were much more abundant and diverse. Among the Triassic crocodile cousins were sharp-toothed carnivores that chased after large prey on two legs, “armadillodiles” covered in bony scutes and spikes, and beaked, almost ostrich-like creatures that gobbled up ferns.

Even as early dinosaurs began to evolve into the main lineages that would thrive during the rest of the Mesozoic, most were small and rare compared to the crocodile cousins. The first big herbivorous dinosaurs, which reached about 27 feet in length, didn’t evolve until near the end of the Triassic, around 214 million years ago. But everything changed at the end of the Triassic. Intense volcanic eruptions in the middle of Pangaea altered the global climate; the gases released into the air caused the world to swing between hot and cold phases. By then, dinosaurs had evolved warm-blooded metabolisms and insulating coats of feathers, leaving them relatively unfazed through the crisis, while many other forms of reptiles perished. Had this mass extinction not transpired, we might have had more of an “Age of Crocodiles”—or at least a very different history with a much broader cast of reptilian characters. The only reason the so-called Age of Dinosaurs came to be is because they got lucky in the face of global extinction.

Prehistoric predators fighting underwater. Illustration.
The biggest predators in the Cretaceous oceans were non-dinosaur reptiles and sharks. De Agostini via Getty Images

Myth: Dinosaurs spanned the entire planet.

Fact: Dinosaurs never evolved to live at sea.

It’s strange to talk about dinosaurs “dominating” an ocean world. While sea levels have risen and fallen over time, the seas make up about 71 percent of Earth’s surface and contain more than 330 million cubic miles of water. The claim that dinosaurs, as diverse as they were, were the dominant form of life on Earth only makes sense if we ignore that three-quarters of our planet is ocean.

Even though some dinosaurs swam, leaving scratches and swim tracks in ancient shallows, none have ever evolved to live their entire lives in the oceans. Even penguins—living dinosaurs—have not evolved the ability to remain at sea like many marine mammals have and must return to land to nest. If we were to emphasize prehistoric oceans, then there were marine reptiles of various shapes and sizes ruling over the watery kingdom. Fish-shaped ichthyosaurs, long-necked and four-flippered plesiosaurs, giant Komodo dragon relatives called mosasaurs, and many more non-dinosaur reptiles thrived in the seas for millions of years, many feeding on the even more abundant coil-shelled cephalopods called ammonites.

Of course, these ecosystems were built on a foundation of plankton. Without disc-shaped algae called coccoliths, the rest of the charismatic swimmers of the Triassic, Jurassic, and Cretaceous wouldn’t have thrived. It’s the abundant, small forms of life that let charismatic creatures like marine reptiles prosper—a further reminder that the animals that impress us on land or sea wouldn’t exist without various tiny organisms that set the foundations of food webs. What we might see as dominance, in any ecosystem, is really a consequence of many relationships and interactions that often go unnoticed.

Two mesonyx, a prehistoric mammal species, standing near a dead animal. Illustration.
Mammals flourished during and after the time of the dinosaurs. The wolf-life Mesonyx emerged in the Eocene, not long after the dinosaurs’ demise. De Agostini via Getty Images

Myth: Dinosaurs suppressed the evolution of mammals.

Fact: Mammals thrived throughout the Age of Dinosaurs.

The classic example of dinosaur dominance is a twitchy little mammal chasing an insect through the Cretaceous night. Dinosaurs would gobble up any beast that got too big or was foolish enough to wander out in the daylight, the argument went, so mammals evolved to be small and nocturnal until the asteroid allowed our ancestors and relatives to emerge from the shadows. The small size and insect-hunting adaptations of some Mesozoic mammals were taken as indicators that mammals were constrained by the success of the dinosaurs, preventing them from becoming larger or opening new niches.

In the past 20 years, however, paleontologists have rewritten the classic story to show that mammals and their relatives thrived alongside the dinosaurs. Throughout the Mesozoic there were furry beasts that swam, dug, glided between the trees, and even ate little dinosaurs. Ancient equivalents of squirrels, raccoons, otters, beavers, sugar gliders, aardvarks, and more evolved through the Jurassic and Cretaceous, including early primates that scampered through the trees over the heads of T. rexes. While it’s true that all the Mesozoic mammals we presently know of were small—the largest was about the size of an American badger— researchers have realized that the way our ancient ancestors interacted with each other was much more important to shaping their evolution than the dinosaurs were. In fact, even with the dinosaurs gone, most new mammal species stuck to being small. We get so hung up on size that we’ve missed the real story, closer to the ground.

Two pterosaurs fighting over prey in flight. Illustration.
Pterosaurs weren’t dinosaurs, but their aerial capabilities gave them an upper hand in the Late Triassic. De Agostini via Getty Images

Myth: Dinosaurs dominated the planet for millions of years.

Fact: No single species can dominate a planet.

Our fixation on a prehistoric hierarchy says more about us than the actual geological record. In our imaginations, we’ve turned dinosaurs into creatures that took over the planet and held on until a cosmic accident wiped them out. Dinosaurs of the Triassic, Jurassic, and Cretaceous lived on every major landmass for more than 150 million years. Often, their supposed reign is compared to what we think of as ours—a paltry 300,000 years that Homo sapiens has been around.  

But the comparison isn’t one-to-one. Dinosaurs were not a single species, but an entire group of organisms. More fundamentally, no species truly stands alone: Even the most long-lived and widespread organisms rely on others. Gigantic, plant-eating dinosaurs had to eat a Mesozoic salad bar of ginkgoes, horsetails, conifers, and other plants—food that required them to have specialized bacteria in their guts for digestion. Even the great T. rex was an ecosystem by itself, preying on herbivores that in turn, ate plants that fostered relationships with fungi and microorganisms in the soil. To look at such an image of life and focus on dominance is looking in the wrong place, dividing the history of life into winners and losers and missing the connections and community required for diverse creatures to thrive. Perhaps dinosaurs can reign supreme in the movies, where we have a perpetual fixation with putting ourselves in the way of their toothy maws. But the real lesson of Triceratops and kin is in how evolution flowers—not who rules the Earth.

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Why are these orcas harassing porpoises? Scientists have 3 theories. https://www.popsci.com/environment/orcas-harass-porpoises/ Fri, 29 Sep 2023 15:00:00 +0000 https://www.popsci.com/?p=576067
A killer whale in the Salish Sea is observed harassing a porpoise, a behavior that has long perplexed scientists.
A killer whale in the Salish Sea is observed harassing a porpoise, a behavior that has long perplexed scientists. Wild Orca

The Southern Resident orcas only eat fish, particularly Chinook salmon.

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A killer whale in the Salish Sea is observed harassing a porpoise, a behavior that has long perplexed scientists.
A killer whale in the Salish Sea is observed harassing a porpoise, a behavior that has long perplexed scientists. Wild Orca

Despite only eating fish, the Southern Resident orcas of the Pacific Northwest’s Salish Sea are known for a perplexing behavior. They harass and even kill porpoises without eating them and scientists are not really sure why. A study published September 28 in the journal Marine Mammal Science looked at over 60 years of data to try and solve this ongoing mystery.

[Related: Raising male offspring comes at a high price for orca mothers.]

While their relatives called transient killer whales eat other organisms including squid, shark, and porpoises, the Southern Resident orcas exclusively eat fish, particularly Chinook salmon. The strange porpoise-harassing behavior was first scientifically documented in 1962. The new study analyzed 78 documented incidents and found three plausible explanations.

Orcas at play

The behavior may be a form of social play for orcas. Like many intelligent species including dogs, elephants, and kangaroos, these whales sometimes engage in playful activities as a way to bond, communicate, or just simply enjoy themselves. Going after porpoises might benefit their group coordination and teamwork.

This theory may be reminiscent of the orcas who became famous for sinking boats in Spain and Portugal. While the Southern Resident killer whales and the whales from the Iberian Peninsula are two different populations with distinct cultures, their affinity for play could be something both populations share, according to the authors of the study

Hunting practice

Going after a larger animal like porpoises might help these whales hone their critical salmon-hunting skills. They may view porpoises as moving targets to practice their hunting techniques, even if a meal is not the end result.

Mismothering behavior

The orcas may be attempting to provide care for porpoises that they perceive as either sick or weak. This could be a behavioral manifestation of their natural inclination to help others within their pod. Female orcas have been observed carrying their deceased calves and have been observed carrying porpoises in a similar manner.  

Scientists also call mismothering behavior displaced epimeletic behavior. It could be due to their limited opportunities to care for their young, according to study co-author and science and research director at Wild Orca Deborah Giles. 

“Our research has shown that due to malnutrition, nearly 70 percent of Southern Resident killer whale pregnancies have resulted in miscarriages or calves that died right away after birth,” Giles said in a statement.

An endangered group

Southern Resident killer whales are considered an endangered population. Currently, only 75 individuals exist and their survival is essentially tied to Chinook salmon. A 2022 study found that these orcas have been in a food deficit for over 40 years and another study found that the older and fatter fish are also becoming more scarce in several populations.

“I am frequently asked, why don’t the Southern Residents just eat seals or porpoises instead?” said Giles. “It’s because fish-eating killer whales have a completely different ecology and culture from orcas that eat marine mammals—even though the two populations live in the same waters. So we must conclude that their interactions with porpoises serve a different purpose, but this purpose has only been speculation until now.”

Even with these three theories for the behavior, the team acknowledges that the exact reason behind porpoise harassment may always remain a mystery. What is clear is that porpoises are not a part of the Southern Resident killer whale diet, so eating them is highly unlikely. 

“Killer whales are incredibly complex and intelligent animals. We found that porpoise-harassing behavior has been passed on through generations and across social groupings. It’s an amazing example of killer whale culture,” Sarah Teman, a study co-author and marine mammal biologist with the University of California, Davis School of Veterinary Medicine’s SeaDoc Society, said in a statement. “Still, we don’t expect the Southern Resident killer whales to start eating porpoises. The culture of eating salmon is deeply ingrained in Southern Resident society. These whales need healthy salmon populations to survive.”

However, this research does underscore the importance of salmon conservation in the Salish Sea and the Southern Resident’s entire range. They generally stay near southern Vancouver Island and Washington State, but their range can extend as far as the central California coast and southeastern Alaska.  Maintaining an adequate salmon supply will be vital to their survival and well-being of the Salish Sea ecosystem as a whole.

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This 6-million-year-old turtle shell still has some DNA https://www.popsci.com/environment/6-million-year-old-turtle-dna/ Fri, 29 Sep 2023 13:00:00 +0000 https://www.popsci.com/?p=575977
The researchers found preserved bone cells in the carapace, which exhibited structures like the nucleus of a cell, where DNA traces were found.
The researchers found preserved bone cells in the carapace, which exhibited structures like the nucleus of a cell, where DNA traces were found. Edwin Cadena/Universidad del Rosario/Smithsonian Tropical Research Institute in Panama

The extracted material could redefine how long DNA and protein can survive in the fossil record.

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The researchers found preserved bone cells in the carapace, which exhibited structures like the nucleus of a cell, where DNA traces were found.
The researchers found preserved bone cells in the carapace, which exhibited structures like the nucleus of a cell, where DNA traces were found. Edwin Cadena/Universidad del Rosario/Smithsonian Tropical Research Institute in Panama

Sea turtles have been around for at least 110 million years, yet relatively little is known about their evolution. Two of the most common sea turtles on Earth are olive ridley and Kemp’s ridley turtles that belong to a genus called Lepidochelys that could help fill in some of the gaps of sea turtle biology and evolution. A team of paleontologists not only discovered the oldest known fossil of turtle from the Lepidochelys genus, but also found some traces of ancient turtle DNA. The findings are detailed in a study published September 28 in the Journal of Vertebrate Paleontology.

[Related: 150 million-year-old turtle ‘pancake’ found in Germany.]

The DNA comes from the remains of a turtle shell first uncovered in 2015 in the Chagres Formation on Panama’s Caribbean coast. It represents the oldest known fossil evidence of Lepidochelys turtles. The turtle lived approximately 6 million years ago, curing the upper Miocene Epoch. At this time, present day Panama’s climate was getting cooler and drier, sea ice was accumulating at Earth’s poles, rainfall was decreasing, sea levels were falling.

“The fossil was not complete, but it had enough features to identify it as a member of the Lepidochelys genus,” study co-author and Universidad del Rosario in Bogotá, Colombia paleontologist Edwin Cadena tells PopSci. Cadena is also a research associate at the Smithsonian Tropical Research Institute in Panama.

The team detected preserved bone cells called osteocytes. These bone cells are the most abundant cells in vertebrates and they have nucleus-like structures. The team used a solution called DAPI to test the osteocytes for genetic material.

“In some of them [the osteocytes], the nuclei were preserved and reacted to DAPI, a solution that allowed us to recognize remains of DNA. This is the first time we have documented DNA remains in a fossilized turtle millions of years old,” says Cadena.

According to the study, fossils like this one from vertebrates preserved in this part of Panama are important for our understanding of the biodiversity that was present when the Isthmus of Panama first emerged roughly 3 million years ago. This narrow strip of land divided the Caribbean Sea and the Pacific Ocean and joined North and South America. It created a land bridge that made it easier for some animals and plants to migrate between the two continents.

[Related: Hungry green sea turtles have eaten in the same seagrass meadows for about 3,000 years.]

This specimen could also have important implications for the emerging field of molecular paleontology. Scientists in this field study ancient and prehistoric biomatter including proteins, carbohydrates, lipids, and DNA that can sometimes be extracted from fossils. 

Molecular paleontology aims to determine if scientists can use this type of evidence to determine more about the organisms than their physical shape, which is typically what is preserved in most fossils. Extracting this tiny material from bones was critical in sequencing the Neanderthal genome, which earned Swedish scientist Svante Pääbo the 2022 Nobel prize in physiology or medicine.

“Many generations have grown up with the idea of extracting and bringing back to life extinct organisms,” says Cadena. “However, that is not the real purpose of molecular paleontology. Instead, its goal is to trace, document, and understand how complex biomolecules such as DNA and proteins can be preserved in fossils.”

This new turtle specimen could help other molecular paleontologists better understand how soft tissues can be preserved over time. It could also shift the idea that original biomolecules like proteins or DNA have a specific timeline for preservation in fossils and encourage re-examining older specimens for traces of biomolecules. 

The post This 6-million-year-old turtle shell still has some DNA appeared first on Popular Science.

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What really happens during a near-death experience https://www.popsci.com/health/near-death-experience/ Fri, 29 Sep 2023 10:00:00 +0000 https://www.popsci.com/?p=575374
A person receiving chest compressions.
Many people resuscitated after cardiac arrest will recall near-death experiences. Depositphotos

Understanding brushes with death could help doctors save more lives.

The post What really happens during a near-death experience appeared first on Popular Science.

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A person receiving chest compressions.
Many people resuscitated after cardiac arrest will recall near-death experiences. Depositphotos

Sci-fi author Brian Herbert once wrote, “The only guarantee in life is death, and the only guarantee in death is its shocking unpredictability.” These words ring true to researchers who investigate what happens in a person’s final moments—and the frustration that comes with these studies. One big problem almost always gets in the way: How do you ask people what dying feels like when they’re no longer here? 

Because we haven’t yet figured out how to communicate with the dead, the best-case scenario is talking to people who have had a close brush with death. They often mention seeing bright lights, their life flashing before their eyes, or visions of deceased loved ones. Some have even reported spotting the Grim Reaper by their bedside. It’s a paradoxical situation, says Kevin Nelson, a professor of neurology at the University of Kentucky: A few perceptions are common—a shining light, for instance—but the near-death experience is unique to each individual.

There’s still a lot of mystery when it comes to the cause, but the field is progressing thanks to people who have allowed scientists to study their brains in these situations. People who have survived these close calls say the encounter can be life-changing. One thing is certain: medical experts say near-death experiences are not a figment of the imagination. 

And figuring out the mechanisms behind this phenomenon goes beyond general curiosity. One goal is to better understand how cardiac arrests happen. It could also potentially save lives, because doctors would have more knowledge for when to continue resuscitations after a patient’s heart stops.

“The research not only benefits our understanding of consciousness, but also in understanding the importance of the heart, lung, and brain in our everyday physiology,” says Jimo Borjigin, an associate professor of neurology at the University of Michigan Medical School.

Unreal recall

A near-death experience can happen to anyone. In fact, 1 in 10 people have reported sharper senses, slowed time, out-of-body sensations or other features associated with near-death, despite not being in grave danger. Research shows that near-death experiences come in four types: emotional, cognitive, spiritual and religious experiences, and supernatural. Of the four, people often recall supernatural activity, particularly the feeling of detaching from a physical body.

About 76 percent of people report an out-of-body experience during a near-death experience. While some people may attribute this to a spiritual experience, this is actually a sensory deception caused by the brain, which scientists have successfully replicated in people who are asleep. Research has shown that direct electrical stimulation of a brain area normally inactive in REM sleep can provoke an out-of-body experience. “Like a flip of a switch, you can literally throw somebody out of their body and back into their body,” Nelson says.

[Related: CPR can save lives. Here’s how (and when) to do it.]

Often, though, people with cardiac arrest will recall near-death experiences. “About a quarter of people who suffer and survived cardiac arrest have memories about some aspect of near-death experience, Borjigin says. This is because people with cardiac arrest have decreasing blood pressure, she says. With the heart unable to pump properly, oxygen is unable to travel to the rest of the body, which is essential for every single cell in your body to survive. When a brain is alerted to a sudden decline in oxygen, your brain undergoes certain changes that contribute to the perceptual distortions that accompany a near-death experience. 

Electrical surges in the brain

Ten years ago, Borjigin and her team observed that rats in simulated cardiac arrest still had fully active brains even 30 seconds after their hearts stopped. What’s more, their brains increased in electrical activity. To confirm whether this happens in humans, Borjigin recently tested the brains of four people who were critically ill and removed from life support.

When these comatose patients were taken off their ventilators, they could not breathe on their own. But, using EEGs, Borjigin noticed two people showed a surge in gamma brainwaves as their bodies started shutting down. Gamma brainwaves are usually a sign of consciousness, because they are mostly active when someone is awake and alert. 

“We’ve shown the brain has a unique mechanism that deals with a lack of oxygen because oxygen is so essential for survival that even an acute loss massively activates the brain and could lead to a near-death experience,” Borjigin explains. 

The boost in gamma waves occurred in a brain area called the temporo-parieto-occipital (TPO) junction. This is responsible for blending information from our senses, including touch, motion, and vision, into our conscious selves. It’s impossible to know if the increased brain activity was related to any visions they may have had, because, sadly, the two patients died. But Borjigin suggests activation of this area suggests people may likely pick up sounds and understand language. “They might hear and perceive the conversation around them and form a visual image in their brain even when their eyes are closed.” 

Hidden consciousness

In one of the largest studies of near-death experiences, an international team of doctors has linked the surge in brain activity to what they called a hidden consciousness immediately following death. In the study, people who were brought back to life through CPR after cardiac arrest could recall memories and conversations while they were seemingly unconscious. 

Between May 2017 and March 2020, the team tracked 567 people who underwent a cardiac arrest. They used EEGs and cerebral oxygenation monitoring to measure electrical activity and brain oxygen levels during CPR. To study auditory and visual awareness, the team used a tablet showing one of 10 images on the screen, and five minutes after, it would play a recording of fruit names: pear, banana, and apple, for another five minutes. 

Only 53 people of the original 567 participants were successfully resuscitated. Initially, they showed no signs of brain activity and were considered dead. But during the CPR, the team noticed bursts of activity. These spikes included gamma waves and others: delta, theta, alpha, and beta waves—all electrical activity that signals consciousness. 

[Related: How your brain conjures dreams]

Twenty-eight of those 53 patients were cognitively capable of having an interview. Eleven people recalled being lucid during CPR, being aware of what was happening or showing perceptions of consciousness like an out-of-body experience. No one could recall the visual image but when asked to randomly name three fruit, one person correctly named all the fruits in the audio recording—though the authors note this could have been a random lucky guess. 

The study authors also included self-reports of 126 other survivors of cardiac arrests not involved in the study and what they remembered from almost dying. Common themes included the pain and pressure of chest compressions, hearing conversations from doctors, out-of-body experiences, and abstract dreams that had nothing to do with the medical event.

The findings debunk the idea that an oxygen-deprived brain stays alive for only five to ten minutes. They also raise the question whether doctors can save people already determined to be dead. “These patients were actually alive within, as seen in the positive waves on the EEG, but externally they were dead,” says Chinwe Ogedegbe, an emergency trauma center section chief and coauthor of the study. 

Beyond the brain’s resilience to the lack of oxygen, the authors propose an alternative “braking system” that could explain the distorted perceptions of consciousness. The brain normally filters and inhibits unneeded information when you’re awake. In this unconscious state, however, the braking system is gone, which could allow dormant brain pathways to activate and access a deeper realm of consciousness containing all of your memory, thoughts, and actions. “Instead of being hallucinatory, illusory or delusional, this appears to facilitate lucid understanding of new dimensions of reality,” the authors write in their paper.

Unfortunately, with only a small number of participants surviving their cardiac arrest, it’s unclear whether this altered consciousness is more visual or auditory. Ogedegbe is working to increase the number of participants in the next trial to 1,500. Doing so will give researchers a better idea of the type of brain activity that goes on when someone is at death’s door, and potentially provide comfort that their loved ones can sense them in their final moments.

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A boiling hot supercontinent could kill all mammals in 250 million years https://www.popsci.com/science/mammals-extinction-volcano-supercontinent/ Thu, 28 Sep 2023 18:00:00 +0000 https://www.popsci.com/?p=575587
A volcano spews lava and ash. In roughly 250 million years, massive tectonic activity could push together all of our current landmasses into a supercontinent like Pangea and make the climate inhospitable to humans and other mammals.
In roughly 250 million years, tectonic activity could push together all of our current landmasses into a supercontinent like Pangea and make the climate inhospitable to humans and other mammals. Deposit Photos

The history and future of mass extinctions.

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A volcano spews lava and ash. In roughly 250 million years, massive tectonic activity could push together all of our current landmasses into a supercontinent like Pangea and make the climate inhospitable to humans and other mammals.
In roughly 250 million years, tectonic activity could push together all of our current landmasses into a supercontinent like Pangea and make the climate inhospitable to humans and other mammals. Deposit Photos

Despite having the critical and even miraculous ingredients to sustain life from microscopic viruses up to big blue whales, planet Earth likely has a future that spells some doom for most, if not all, species of mammals—including humans. A study published September 25 in the journal Nature Geosciences made the bold prediction that in about 250 million years, all of Earth’s major land masses will join together as one. When they do, it could make our planet one extremely hot and almost completely uninhabitable for mammals.

[Related: Mixing volcanic ash with meteorites may have jump-started life on Earth.]

“Widespread temperatures of between 40 to 50 degrees Celsius [104 to 122 degrees Fahrenheit], and even greater daily extremes, compounded by high levels of humidity would ultimately seal our fate,” study co-author and University of Bristol paleoclimatologist Alexander Farnsworth said in a statement. “Humans—along with many other species—would expire due to their inability to shed this heat through sweat, cooling their bodies.”

The models in this study predict that CO2 levels would rise to between 410 parts per million and 816 parts per million in a few million years This is roughly the same as today’s level, which is already pushing the planet into dangerously hot water, or up to twice as high.

“They do explain quite nicely that it’s a combination of both those factors, kind of a double whammy situation,” geophysicist Ross Mitchell of the Chinese Academy of Sciences, who was not involved in the study, told Science magazine. “If there’s any disagreement I have with this paper, it’s that they’re more right than they thought they were.”

This prediction aligns well with Earth’s past periods of mass extinction and the volatile history of our planet. Here are some other times that mammalian and human life on Earth was almost completely wiped out.

The Pleistocene Ancestral Bottleneck

About 800,000 to 900,000 years ago, the population of human ancestors drastically dropped. A study published in August estimates that there were only about 1,280 breeding individuals alive during this transition between the early and middle Pleistocene. About 98.7 percent of the ancestral population was lost at the beginning of this ancestral bottleneck that lasted for roughly 117,000 years.

During this time, modern humans spread outside of the African continents and other early human species like Neanderthals began to go extinct. The Australian continent and the Americas also saw humans for the first time and the climate was generally cold. 

Some of the potential reasons behind this population drop are mostly related to extremes in climate. Temperatures changed, severe droughts persisted, and food sources may have dwindled as animals like mammoths, mastodons, and giant sloths went extinct. According to the study, an estimated 65.85 percent of current genetic diversity may have been lost due to this bottleneck.

[Related: We’re one step closer to identifying the first-ever mammals.]

The Great Dying

About 250 million years ago, massive volcanic eruptions triggered catastrophic climate changes that killed 80 to 90 percent of species on Earth. The Permian-Triassic mass extinction, or the “Great Dying,” paved the way for dinosaurs to dominate Earth, but was even worse than the Cretaceous–Paleogene extinction that wiped out the dinosaurs 66 million years ago.

According to a study published in May, saber-toothed creature called Inostrancevia filled a gap in southern Pangea’s ecosystem, when it was already devoid of top predators. Eventually, Inostrancevia also went extinct about 252 million years ago, as Earth’s species fought to gain a foothold on a changing planet. 

This example of how the past is prologue also bears a warning for our future, since the team says The Great Dying is the historical event that most closely parallels Earth’s current environmental crisis.

“Both involve global warming related to the release of greenhouse gasses, driven by volcanoes in the Permian and human actions currently,” study co-author museum curator and paleontologist Christian Kammerer told PopSci in May. “[They] represent a very rare case of rapid shifts between icehouse and hothouse Earth. So, the turmoil we observe in late Permian ecosystems, with whole sections of the food web being lost, represents a preview for our world if we don’t change things fast.”

The Ultimate Mammalian Survivor

Despite Earth constantly trying to kill us, life finds a way. Some of our very early ancestors potentially even shared a brief moment with Titanosaurs and the iconic Triceratops. These distant mammalian relatives also survived the Earth’s most famous mass extinction event: the Cretaceous-Paleogene (K-Pg) mass extinction that wiped out non-avian dinosaurs on a spring day about 66 million years ago.

[Related: This badger-like mammal may have died while trying to eat a dinosaur.]

A study published in June revealed that a Cretaceous origin for placental mammals, the diverse group that includes humans, dogs, and bats, briefly co-existed with dinosaurs. After an asteroid struck the Earth near Mexico’s Yucatán Peninsula, the devastation in its wake wiped out all of the non-avian dinosaurs and many mammals, such as a Madagascan rodent-looking animal named Vintana sertichi  that weighed up to 20 pounds Scientists have long debated if placental mammals were present with the dinosaurs before the Cretaceous-Paleogene (K-Pg) mass extinction, or if they only evolved after the dinosaurs died out. 

This study used statistical analysis that showed groups that include primates, rabbits and hares (Lagomorpha), and dogs and cats (Carnivora) evolved just before the K-Pg mass extinction and the impact that the modern lines of today’s placental mammals started to take shape after the asteroid hit. As with other mammals, they likely began to diversify once the dinosaurs were out of the picture.

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How carrots get their trademark orange color https://www.popsci.com/health/orange-carrot-gene/ Thu, 28 Sep 2023 16:00:00 +0000 https://www.popsci.com/?p=575550
A row of organic orange carrots with their green stems still attached on a table.
While carrots come in many colors, orange carrots have been the most popular due to their sweetness and color. Deposit Photos

A surprisingly low number of recessive genes give the tasty root its signature hue.

The post How carrots get their trademark orange color appeared first on Popular Science.

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A row of organic orange carrots with their green stems still attached on a table.
While carrots come in many colors, orange carrots have been the most popular due to their sweetness and color. Deposit Photos

Most nutritionists advise people to “eat the rainbow” to balance their diet—think greens like kale, purples like eggplant, reds like tomatoes.  Consuming nutritious and naturally occuring orange foods like carrots packed with vitamin A, fiber, antioxidants, and pigments called carotenoids is a must to get a full and healthy spectrum. Carotenoids even got their name because they were first isolated from carrots.  But what is exactly behind the bright hue of some of our favorite carrots? Only three specific genes are required to give orange carrots their signature color, according to a study published September 28 in the journal Nature Plants.

[Related: Carrots were once a crucial tool in anti-Nazi propaganda.]

In the study, a team from North Carolina State University and the University of Wisconsin-Madison looked at the genetic blueprints of more than 600 varieties of carrots. Surprisingly, they found that these three required genes all need to be recessive, or turned off.

“Normally, to make some function, you need genes to be turned on,” study co-author and North Carolina State University horticultural scientist Massimo Iorizzo said in a statement.  “In the case of the orange carrot, the genes that regulate orange carotenoids—the precursor of vitamin A that have been shown to provide health benefits—need to be turned off,” Iorizzo said. 

In 2016, this team sequenced the carrot genome for the first time and also uncovered the gene involved in the pigmentation of yellow carrot. For this new study, they sequenced 630 carrot genomes as part of a continuing study on the history and domestication of the crunchy root veggie.

The team performed selective sweeps, or structural analyses among five different carrot groups. During these sweeps, they looked for areas of the genome that are heavily selected in certain groups. They found that many of the genes involved in flowering were under selection, primarily to delay the flowering process. This event causes the edible root that we eat called the taproot to turn woody and inedible. 

“We found many genes involved in flowering regulation that were selected in multiple populations in orange carrot[s], likely to adapt to different geographic regions,” said Iorizzo. 

Additionally, the study created a general timeline of carrot domestication and found more evidence that carrots were domesticated in the 9th or 10th century CE in western and central Asia. 

“Purple carrots were common in central Asia along with yellow carrots. Both were brought to Europe, but yellow carrots were more popular, likely due to their taste,” said Iorizzo.

[Related: WTF are purple carrots and where did they come from?]

In about the 15th or 16th century, orange carrots made their appearance in western Europe, potentially as the result of crossing a yellow carrot with a white one. The bright color and sweet flavor of orange carrots likely made it more popular than other varieties, so farmers continued selecting for them. In northern Europe, different types of orange carrots were developed in the 16th and 17th centuries and orange carrots of various shades can be seen in paintings from that area. They continued to grow in popularity as more understanding about the importance of alpha- and beta-carotenes and vitamin A in the diet for eye health progressed in the late 19th and early 20th centuries. 

The findings in this study shed more light on the traits that are important to improving carrots and could lead to better health benefits from the nutritious vegetable.

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How many ancient humans does it take to fight off a giant hyena? https://www.popsci.com/science/human-hyena-scavenger-pleistocene/ Thu, 28 Sep 2023 15:00:00 +0000 https://www.popsci.com/?p=575558
A hyenea shows its jaws. Giant hyenas went extinct about 500,000 years ago, but were roughly 240 pounds and skilled scavengers like their modern counterparts.
Giant hyenas went extinct about 500,000 years ago, but were roughly 240 pounds and skilled scavengers like their modern counterparts. Deposit Photos

During the Pleistocene, competition was tough even for scraps.

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A hyenea shows its jaws. Giant hyenas went extinct about 500,000 years ago, but were roughly 240 pounds and skilled scavengers like their modern counterparts.
Giant hyenas went extinct about 500,000 years ago, but were roughly 240 pounds and skilled scavengers like their modern counterparts. Deposit Photos

One of the most enduring mysteries about our earliest ancestors and extinct human relatives is how they ate and procured enough food to sustain themselves millions of years ago. We believe that archery first arrived in Europe about 54,000 years ago and Neanderthals were cooking and eating crab about 90,000 years ago, but scavenging was likely necessary to get a truly hearty meal. A modeling study published September 28 in the journal Scientific Reports found that groups of hominins roughly 1.2 to 0.8 million years ago in southern Europe may have been able to compete with giant hyenas for carcasses of animals abandoned by larger predators like saber-toothed cats.

[Related: An ‘ancestral bottleneck’ took out nearly 99 percent of the human population 800,000 years ago.]

Earlier research has theorized that the number of carcasses abandoned by saber-toothed cats may have been enough to sustain some of southern Europe’s early hominin populations. However, it’s been unclear if competition from giant hyenas (Pachycrocuta brevirostris) would have limited hominin access to this food source. These extinct mongoose relatives were about 240 pounds–roughly the size of a lioness–and went extinct about 500,000 years ago. 

“There is a hot scientific debate about the role of scavenging as a relevant food procurement strategy for early humans,” paleontologist and study co-author Jesús Rodríguez from the National Research Center On Human Evolution (CENIEH) in Burgos, Spain tells PopSci. “Most of the debate is based on the interpretation of the scarce and fragmentary evidence provided by the archaeological record. Without denying that the archaeological evidence should be considered the strongest argument to solve the question, our intention was to provide elements to the debate from a different perspective.”

For this study, Rodríguez and co-author Ana Mateos looked at the Iberian Peninsula in the late-early Pleistocene era. They ran computer simulations to model competition for carrion–the flesh of dead animals–between hominins and giant hyenas in what is now Spain and Portugal. They simulated whether saber-toothed cats and the European jaguar could have left enough carrion behind to support both hyena and hominin populations—and how this may have been affected by the size of scavenging groups of hominins. 

They found that when hominins scavenged in groups of five or more, these groups could have been large enough to chase away giant hyenas. The hominin populations also exceeded giant hyena populations by the end of these simulations. However, when the hominins scavenged in very small groups, they could only survive to the end of the simulation when the predator density was high, which resulted in more carcasses to scavenge.  

[Related: Mysterious skull points to a possible new branch on human family tree.]

According to their simulations, the potential optimum group size for scavenging hominins was just over 10 individuals. This size was large enough to chase away saber-toothed cats and jaguars. However, groups of more than 13 individuals would have likely required more carcasses to sustain their energy expenditure. The authors caution that their simulations couldn’t specify this exact “just right” group size, since the numbers of hominins needed to chase away hyenas, saber-toothed cats, and jaguars were pre-determined and arbitrarily assigned.

“The simulations may not determine the exact value of the optimum, but show that it exists and depends on the number of hominins necessary to chase away the hyenas and of the size of the carcasses,” says Rodríguez.

Scavenged remains may have been an important source of meat and fat for hominins, especially in winter when plant resources were scarce. This team is working on simulating the opportunities hominins had for scavenging in different ecological scenarios in an effort to change a view that scavenging is marginal and that hunting is a more “advanced” and more “human” behavior than scavenging. 

“The word for scavenger in Spanish is ‘carroñero.’ It has a negative connotation, and is frequently used as an insult. We do not share that view,” says Rodríguez. “Scavengers play a very important role in ecosystems, as evidenced by the ecological literature in the last decades. We view scavenging as a product of the behavioral flexibility and cooperative abilities of the early hominins.”

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A fossilized trilobite stomach can show us clues to Cambrian cuisine https://www.popsci.com/environment/trilobite-fossil-stomach/ Wed, 27 Sep 2023 15:30:00 +0000 https://www.popsci.com/?p=575001
An illustration of Bohemolichas feeding on the seafloor, moments before it is engulfed, buried, and preserved by an underwater mud flow.
An illustration of Bohemolichas feeding on the seafloor, moments before it is engulfed, buried, and preserved by an underwater mud flow. Jiri Svoboda

The 465-million-year-old gut contents reveal similarities between the ancient arthropod and modern crabs.

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An illustration of Bohemolichas feeding on the seafloor, moments before it is engulfed, buried, and preserved by an underwater mud flow.
An illustration of Bohemolichas feeding on the seafloor, moments before it is engulfed, buried, and preserved by an underwater mud flow. Jiri Svoboda

About 465 million years ago, a now extinct arthropod called a trilobite was eating its way across the present day Czech Republic. After it died, the passage of time actually preserved the plentiful contents of this specimen’s prehistoric guts. A team of paleontologists is using this full fossilized belly to learn more about the feeding habits and lifestyle of these common fossilized arthropods. The findings are detailed in a study published September 27 in the journal Nature.

[Related: Trilobites may have jousted with head ‘tridents’ to win mates.]

More than 20,000 species of trilobite lived during the early Cambrian to the end-Permian period roughly 541 to 252 million years ago. They are some of the most common fossil specimens from this time period, yet paleontologists do not know much about their feeding habits since gut contents usually disappear over time, and until recently there were no known fossil specimens with them intact.

In the study, a team from institutions in Sweden and the Czech Republic examined a fossil specimen of Bohemolichas incola first uncovered near Prague over 100 years ago. Study co-author and paleontologist Petr Kraft from Charles University in Prague had long suspected that this specimen may have a gut full of food intact, but did not have a suitable technique to look inside the trilobite’s innards. Study co-authors and paleontologists Valéria Vaskaninova and Per Ahlberg from Uppsala University in Sweden suggested using a synchrotron in one of their fossil scanning sessions. This machine is a large electron accelerator that produces powerful laser-like x-rays to take high-quality scans of the fossil

“The results were fantastic, showing all the gut contents in detail so that we could identify what the trilobite had been eating,” Ahlberg tells PopSci. “Remains of ostracods (small shell-bearing crustaceans, still around today), hyoliths (extinct cone-shaped animals of uncertain affinities) and stylophorans (extinct echinoderms that look like little armor-plated electric guitars). These are all kinds of animals that lived in the local environment.”

The team believes that Bohemolichas incola was likely an opportunistic scavenger. It also was potentially a light crusher and a chance feeder, which means that it ate both dead or living animals, which either disintegrated easily or were actually small enough to be swallowed whole. However, after this particular Bohemolichas incola died, the circle of life continued and the scavenger became the scavenged. Vertical tracks of other scavengers were found on the specimen. These unknown creatures burrowed into this trilobite’s carcass and targeted its soft tissue, but avoided its gut. Staying away from the gut implies that there were some noxious conditions inside Bohemolichas incola’s digestive system and potentially ongoing enzymatic activity.

[Related: These ancient trilobites are forever frozen in a conga line.]

“We were able to draw conclusions about the chemical environment inside the gut of the living trilobite. The shell fragments on the gut have not been etched by stomach acids, and this shows that the gut pH must have been close to neutral, similar to the condition in modern crabs and horseshoe crabs,” says Ahlberg. “This may indeed be a very ancient shared characteristic of trilobites and these modern arthropods.”

Future studies into trilobites could use similar techniques to look for more gut fills. Since this group is a very diverse group of animals, it can’t be assumed that this particular species is representative of the feeding habits for all. 

“This project shows how cutting-edge technology can come together with really old museum specimens. The trilobite was collected in 1908, and has been in a museum ever since, but it is only now that we have the technology to unlock its secrets,” says Ahlberg. “This illustrates not only the rapid technological progress of our time, but also the importance of well-maintained museum collections.”

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Mysterious ‘fairy circles’ may appear on three different continents https://www.popsci.com/science/fairy-circles-desert-ai/ Wed, 27 Sep 2023 14:00:00 +0000 https://www.popsci.com/?p=575087
Aerial view of a hot air balloon over Namib desert. The circular “fairy circles” are derived from any vegetation & surrounded by tall grass.
Aerial view of a hot air balloon over Namib desert. The circular “fairy circles” are derived from any vegetation & surrounded by tall grass. Getty Images

Researchers used AI to comb the world's deserts for the natural phenomena, but debate continues.

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Aerial view of a hot air balloon over Namib desert. The circular “fairy circles” are derived from any vegetation & surrounded by tall grass.
Aerial view of a hot air balloon over Namib desert. The circular “fairy circles” are derived from any vegetation & surrounded by tall grass. Getty Images

The natural circles that pop up on the soil in the planet’s arid regions are an enduring scientific debate and mystery. These “fairy circles” are circular patterns of bare soil surrounded by plants and vegetation. Until very recently, the unique phenomena have only been described in the vast Namib desert and the Australian outback. While their origins and distribution are hotly debated, a study with satellite imagery published on September 25 in the journal Proceedings of the National Academy of Sciences (PNAS) indicates that fairy circles may be more common than once realized. They are potentially found in 15 countries across three continents and in 263 different sites. 

[Related: A new study explains the origin of mysterious ‘fairy circles’ in the desert.]

These soil shapes occur in arid areas of the Earth, where nutrients and water are generally scarce. Their signature circular pattern and hexagonal shape is believed to be the best way that the plants have found to survive in that landscape. Ecologist Ken Tinsly observed the circles in Namibia in 1971, and the story goes that he borrowed the name fairy circles from a naturally occurring ring of mushrooms that are generally found in Europe.

By 2017, Australian researchers found the debated western desert fairy circles, and proposed that the mechanisms of biological self-organization and pattern formation proposed by mathematician Alan Turing were behind them. In the same year, Aboriginal knowledge linked those fairy circles to a species of termites. This “termite theory” of fairy circle origin continues to be a focus of research—a team from the University of Hamburg in Germany published a study seeming to confirm that termites are behind these circles in July.

In this new study, a team of researchers from Spain used artificial intelligence-based models to look at the fairy circles from Australia and Namibia and directed it to look for similar patterns. The AI scoured the images for months and expanded the areas where these fairy circles could exist. These locations include the circles in Namibia, Western Australia, the western Sahara Desert, the Sahel region that separates the African savanna from the Sahara Desert, the Horn of Africa to the East, the island of Madagascar, southwestern Asia, and Central Australia.

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Fairy circles on a Namibian plain. CREDIT: Audi Ekandjo.

The team then crossed-checked the results of the AI system with a different AI program trained to study the environments and ecology of arid areas to find out what factors govern the appearance of these circular patterns. 

“Our study provides evidence that fairy-circle[s] are far more common than previously thought, which has allowed us, for the first time, to globally understand the factors affecting their distribution,” study co-author and Institute of Natural Resources and Agrobiology of Seville soil ecologist Manuel Delgado Baquerizo said in a statement

[Related: The scientific explanation behind underwater ‘Fairy Circles.’]

According to the team, these circles generally appear in arid regions where the soil is mainly sandy, there is water scarcity, annual rainfall is between 4 to 12 inches, and low nutrient continent in the soil.

“Analyzing their effects on the functioning of ecosystems and discovering the environmental factors that determine their distribution is essential to better understand the causes of the formation of these vegetation patterns and their ecological importance,” study co-author and  University of Alicante data scientist Emilio Guirado said in a statement

More research is needed to determine the role of insects like termites in fairy circle formation, but Guirado told El País that “their global importance is low,” and that they may play an important role in local cases like those in Namibia, “but there are other factors that are even more important.”

The images are now included in a global atlas of fairy circles and a database that could help determine if these patterns demonstrate resilience to climate change. 

“We hope that the unpublished data will be useful for those interested in comparing the dynamic behavior of these patterns with others present in arid areas around the world,” said Guirado.

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The mathematical theory that connects swimming sperm, zebra stripes, and sunflower seeds https://www.popsci.com/science/alan-turing-pattern-zebra-sperm/ Wed, 27 Sep 2023 13:00:00 +0000 https://www.popsci.com/?p=574986
A close up of the black and white stripes of a zebra. The same patterns that dictate zebra stripes could also control the way sperm swim.
Recognizable patterns in nature may appear spontaneously when chemicals within the objects or organisms diffuse and then react together. Deposit Photos

Scientists inch closer to understanding the very basis of nature’s patterns.

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A close up of the black and white stripes of a zebra. The same patterns that dictate zebra stripes could also control the way sperm swim.
Recognizable patterns in nature may appear spontaneously when chemicals within the objects or organisms diffuse and then react together. Deposit Photos

In nature, patterns of chemical interactions between two different substances are believed to govern the designs our eyes see—for example, a zebra’s stripes. These stripey designs are governed by a mathematical basis that is potentially overseeing another completely unrelated thing—the wavy patterns formed by sperm’s motion. According to a study published September 27 in the journal Nature Communications, the same mathematical theory could traverse both.

[Related: Monarch butterflies’ signature color patterns could inspire better drone design.]

To understand the connection, we need to go back more than 70 years. The wavy undulations of a sperm’s tail—or flagella—make striped patterns in space-time. These patterns potentially follow the same template proposed by mathematician Alan Turing, one of the most famous scientists of the 20th century. Turing is most well-known for helping crack the enigma code during World War II and ushering in a new age of computer science, but he also developed a theory informally called the reaction-diffusion theory for pattern formation. This 1952 theory predicted that recognizable patterns in nature may appear spontaneously when chemicals within the objects or organisms diffuse and then react together.

While this theory hasn’t been well proven by experimental evidence, Turing’s theory sparked more research into using reaction-diffusion mathematics as a way to understand natural patterns. These so-called Turing patterns are believed to govern leopard spots, whorls of seeds in sunflower heads, and even patterns of sand on the beach. 

In this new study, a team from the University of Bristol in England used Turing patterns as a way to look at the movement of sperm’s flagella and vibrating hair-like cells called cilia. 

“Live spontaneous motion of flagella and cilia is observed everywhere in nature, but little is known about how they are orchestrated,” study co-author and mathematician Hermes Gadêlha said in a statement. “They are critical in health and disease, reproduction, evolution, and survivorship of almost every aquatic microorganism [on] earth.”

Flagellar undulations are believed to make stripe patterns in space-time, in the form of the waves that travel along the tail to drive the sperm forward when it is in fluid. To look deeper, Gadêlha and his team used mathematical modeling, simulations, and data fitting to show that wavy flagellar movement can actually arise spontaneously without the influence of the fluid in their environment. According to the team, this is mathematically equivalent to Turing’s reaction-diffusion system that was first proposed for chemical patterns over 70 years ago.

For the swimming sperm, chemical reactions of molecular motors power its tail and the bending movement diffuses along the tail in waves. The fluid itself is playing a very minor role on how the tail moves.

[Related: The genes behind your fingerprints just got weirder.]

“We show that this mathematical ‘recipe’ is followed by two very distant species—bull sperm and Chlamydomonas (a green algae that is used as a model organism across science), suggesting that nature replicates similar solutions,” said Gadêlha. “Traveling waves emerge spontaneously even when the flagellum is uninfluenced by the surrounding fluid. This means that the flagellum has a fool-proof mechanism to enable swimming in low viscosity environments, which would otherwise be impossible for aquatic species. It is the first time that model simulations compare well with experimental data.”

The findings of this study could help understand fertility issues associated with abnormal flagellar motion, diseases caused by ineffective cilia, and be applied to robotics. Other models in nature may exist that could provide further experimental proof of Turing’s template, but more research is needed.  

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Meet the first electric blue tarantula known to science https://www.popsci.com/environment/meet-the-first-electric-blue-tarantula-known-to-science/ Tue, 26 Sep 2023 16:00:00 +0000 https://www.popsci.com/?p=574604
A tarantula with a mostly black body, but bright blue legs and pincers. Chilobrachys natanicharum is the first tarantula species found in Thailand’s mangrove trees. CREDIT: Yuranan Nanthaisong/ZooKeys.
Chilobrachys natanicharum is the first tarantula species found in Thailand’s mangrove trees. CREDIT: Yuranan Nanthaisong/ZooKeys. Yuranan Nanthaisong/ZooKeys

The new tarantula species, with its extremely rare color, was found in a mangrove tree in Thailand.

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A tarantula with a mostly black body, but bright blue legs and pincers. Chilobrachys natanicharum is the first tarantula species found in Thailand’s mangrove trees. CREDIT: Yuranan Nanthaisong/ZooKeys.
Chilobrachys natanicharum is the first tarantula species found in Thailand’s mangrove trees. CREDIT: Yuranan Nanthaisong/ZooKeys. Yuranan Nanthaisong/ZooKeys

Scientists in Thailand have discovered a new species of tarantula with a very unique blue hue. The tarantula is named Chilobrachys natanicharum and is also called the electric blue tarantula. The findings were described in a study published September 18 in the journal ZooKeys 

[Related: Before spider mites mate, one of them gets their skin removed.]

The new colorful arachnid was discovered in southern Thailand’s Phang-Nga province. It follows the identification of another new species of tarantula called Taksinus bambus, or the bamboo culm tarantula.

“In 2022, the bamboo culm tarantula was discovered, marking the first known instance of a tarantula species living inside bamboo stalks,” study co-author and Khon Kaen University entomologist Narin Chomphuphuang said in a statement. “Thanks to this discovery, we were inspired to rejoin the team for a fantastic expedition, during which we encountered a captivating new species of electric blue tarantula.”

The team that found the first not-so-blue bamboo culm tarantula included a local wildlife YouTuber named JoCho Sippawat. This year, Chomphuphuang joined up with Sippawat for a surveying expedition in the province to learn more about tarantula diversity and distribution. They identified this new species by this very distinctive coloration during the expedition.

“The first specimen we found was on a tree in the mangrove forest. These tarantulas inhabit hollow trees, and the difficulty of catching an electric-blue tarantula lies in the need to climb a tree and lure it out of a complex of hollows amid humid and slippery conditions,” Narin said. “During our expedition, we walked in the evening and at night during low tide, managing to collect only two of them.”

Chilobrachys natanicharum has blue coloring due to the unique structure of its hair and not the presence of blue pigments. CREDIT: Yuranan Nanthaisong
Chilobrachys natanicharum has blue coloring due to the unique structure of its hair and not the presence of blue pigments. CREDIT: Yuranan Nanthaisong

The color blue is very rare in nature. It can even exist in other animals that aren’t usually this color, including the blue lobsters that have recently been found in Massachusetts and France. Some animals also evolved wild colors including blues, yellows, and reds to appear poisonous to try and keep other animals from eating them.  

In order for an organism to appear blue, it must absorb very small amounts of energy while reflecting high-energy blue light. Since penetrating molecules that are capable of absorbing this energy is a complex process, the color blue is less common than other colors in the natural world. 

According to the study, the secret behind the electric blue tarantula’s wild color comes from the unique structure of their hair and not from a presence of blue pigment. Their hair incorporates nanostructures that manipulate the light shining on it to create the blue appearance. Their hair can also display a more violet hue depending on the light, which creates an iridescent effect. 

[Related: Blue-throated macaws are making a slow, but hopeful, comeback.]

This species was previously found on the commercial tarantula market, but there hadn’t been any documentation describing its natural habitat or unique features. 

“The electric blue tarantula demonstrates remarkable adaptability. These tarantulas can thrive in arboreal as well as terrestrial burrows in evergreen forests,” Narin said. “However, when it comes to mangrove forests, their habitat is restricted to residing inside tree hollows due to the influence of tides.”

To name the new species, the authors conducted an auction campaign and the scientific name of Chilobrachys natanicharum was selected. It is named after executives Natakorn and Nichada Changrew of Nichada Properties Co., Ltd., Thailand and the proceeds of the auction were donated to support the education of Indigenous Lahu children in Thailand and for cancer patients in need of money for treatment.

CREDIT: JoCho Sippawat/Pensoft Publishers.

The authors say that this discovery points to the continued importance of taxonomy as a basic aspect of research and conservation. It also highlights the need to protect mangrove forests from continued deforestation, as the electric blue tarantula is also one of the world’s rarest tarantulas. 

“This raises a critical question: Are we unintentionally contributing to the destruction of their natural habitats, pushing these unique creatures out of their homes?” the researchers ask in their conclusion.

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Earth’s stinkiest flower is threatened with extinction https://www.popsci.com/environment/earths-stinkiest-flower-extinction/ Mon, 25 Sep 2023 18:15:00 +0000 https://www.popsci.com/?p=574123
Rafflesia kemumu in the rainforest of Sumatra.
Rafflesia kemumu in the rainforest of Sumatra. Flowers in the Rafflesia genus are some of the world's largest, but also smelliest. Chris Thorogood

Rafflesia, which smells like rotting flesh, is facing habitat loss.

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Rafflesia kemumu in the rainforest of Sumatra.
Rafflesia kemumu in the rainforest of Sumatra. Flowers in the Rafflesia genus are some of the world's largest, but also smelliest. Chris Thorogood

As their giant petals open, the blooming of flowers in the genus Rafflesia brings with them an overwhelming odor mimics the smell of rotting flesh. While their pungent stink might keep humans away and attract flies, a study published September 19 in the journal Plants People Planet found that 67 percent of the habitats for these notorious plants is at risk of destruction. 

[Related: Corpse flowers across the country are swapping pollen to stay stinky.]

Rafflesia are the largest flowers in the world and have been a botanical enigma for centuries. In addition to their infamous stink, corpse flowers are actually a parasite that infects vines in the tropical jungles of Thailand, Indonesia, Malaysia, Brunei, and the Philippines. It remains hidden from sight for the majority of its lifecycle, existing as a system of tiny thread-like filaments that invades its host. At unpredictable intervals, the parasite produces a cabbage-like bud that will break through a vine’s bark and eventually form a giant, five-lobed flower, up to 3.2 feet across. The flower produces its signature rotten meat smell to attract pollinating flies.

This elusive lifecycle and ability to remain hidden makes them very poorly understood by botanists, and new species are still being discovered by botanists. With such an elusive lifecycle, Rafflesia remains poorly understood, and new species are still being recorded. 

In the study, an international group of researchers established the first coordinated global network to assess the threats facing Rafflesia. This network found most of the 42 known species of Rafflesia are severely threatened, but only one is listed on the IUCN’s Red List of Threatened Species. This leaves many unprotected by regional or national conservation strategies. The scientists classified 25 species as Critically Endangered and 15 as Endangered, according to the IUCN’s criteria for classification

Rafflesia bengkuluensis with its custodians in Sumatra. CREDIT: Chris Thorogood
Rafflesia bengkuluensis with its custodians in Sumatra. CREDIT: Chris Thorogood

Chris Thorogood of the University of Oxford Botanic Garden in England co-authored the study and an upcoming book on the team’s years devoted to documenting these plants. In a statement, Thorogood said that this work, “Highlights how the global conservation efforts geared towards plants–however iconic–have lagged behind those of animals. We urgently need a joined-up, cross-regional approach to save some of the world’s most remarkable flowers, most of which are now on the brink of being lost.”

Additionally, Rafflesia species often have very restricted geographical distributions, making them particularly vulnerable to habitat destruction. Many of the remaining populations of corpse flowers have only a few individuals in unprotected areas that are at risk of being converted for agricultural use, according to the study. While these and other similarly smelly flowers famously exist in some botanical gardens, these institutions have had limited success in breeding them, making habitat conservation an urgent priority.

[Related: These parasitic plants force their victims to make them dinner.]

The four-point action plan proposed by the team for local governments, research centers, and conservation organizations  includes greater habitat protections, better understanding of the full diversity of the Rafflesia that exists to better inform policy making, developing better methods to breed them outside their native habitat, and introducing new ecotourism initiatives to engage local communities in Rafflesia conservation.

The study also highlighted some valuable success stories that may offer important insights for Rafflesia conservation elsewhere, including the Bogor Botanic Garden in West Java, Indonesia, that saw a series of successful blooming events and villagers in West Sumatra benefitting from Rafflesia ecotourism by forming “pokdarwis” or tourism awareness groups linked to social media.

“Indigenous peoples are some of the best guardians of our forests, and Rafflesia conservation programmes are far more likely to be successful if they engage local communities,” Adriane Tobias, a study co-author and forester from the University of the Philippines Los Baños, said in a statement. “Rafflesia has the potential to be a new icon for conservation in the Asian tropics.”

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The deepest known ocean virus lives under 29,000 feet of water https://www.popsci.com/environment/deepest-virus/ Mon, 25 Sep 2023 13:30:00 +0000 https://www.popsci.com/?p=573884
A high-density field of corals, including the spiraling Iridogorgia magnispiralis. Image courtesy of the NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.
A high-density field of corals, including the spiraling Iridogorgia magnispiralis. Image courtesy of the NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas. NOAA

The newly discovered virus vB_HmeY_H4907 lurks in the Mariana Trench.

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A high-density field of corals, including the spiraling Iridogorgia magnispiralis. Image courtesy of the NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.
A high-density field of corals, including the spiraling Iridogorgia magnispiralis. Image courtesy of the NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas. NOAA

Marine virologists have found a novel virus living in the incredibly deep and dark Mariana Trench, more than 29,000 feet under the ocean’s surface. The virus is the deepest known isolated bacteriophage—viruses that infect and replicate inside bacteria—ever found, according to a study published September 20 in the journal Microbiology Spectrum.

[Related: Meet the marine geologist mapping the deepest point on Earth.]

The enormous trench in the western Pacific Ocean near Guam is over 36,000 feet deep at its lowest depth and is part of the hadal zone. This zone is named for Hades, the Greek god of the underworld, for its deep trenches and high pressures. The buildup of carbon along the base of the hadal zone’s trenches may even help regulate the Earth’s climate and carbon cycle. Even in its intense pressures and extreme cold and darkness, life continues to find a way. Scientists have discovered fish, shrimp, and lots of microbes lurking there. That life includes regulators to keep the living things in check. 

“Wherever there’s life, you can bet there are regulators at work. Viruses, in this case,” study co-author and Ocean University of China marine virologist Min Wang said in a statement.

This new phage works by infecting bacteria in the phylum Halomonas, which are commonly found in sediments deep seas and the geyser-like openings on the seafloor that release streams of hot water called hydrothermal vents.

In their study, Wang and an international group of researchers describe the new virus identified as vB_HmeY_H4907. The virus was brought up in sediment from a depth of about 5.5 miles or more than 29,000 feet deep and is classified as a bacteriophage. Also called phage, they infect and replicate inside bacteria and are believed to be the most abundant life forms on Earth.

“To our best knowledge, this is the deepest known isolated phage in the global ocean,” said Wang.

According to Wang, the analysis of the viral genetic material points to the existence of a previously unknown viral family living in the deep ocean and some new insights into the evolution, genetic diversity, genomic features of deep-sea phages and how they interact with their hosts. 

Previously, this team has used metagenomic analysis to study the viruses that infect bacteria in the order Oceanospirallales. This order includes Halomonas, the phylum that this newly discovered virus infects. In this new study, the team searched for viruses in bacterial strains isolated by marine virologist Yu-Zhong Zhang, also from the Ocean University of China. 

[Reading: A deep sea mining zone in the remote Pacific is also a goldmine of unique species.]

The genomic analysis of the new virus suggests that it has a similar structure to its host and is widely distributed in the ocean. It is also lysogenic, meaning it invades and replicates inside its host, but typically does not kill the bacterial cell. The virus’s genetic material is then copied and passed on as the cells divide.

The discovery points to some new questions focused on the survival strategies that viruses living in harsh and generally secluded environments like the hadal zone trenches use and how they co-evolve with their hosts. Future studies also will aim to investigate the molecular machinery driving interactions between deep-sea viruses and their hosts. 

According to Wang, discovering more new viruses in extreme places, “would contribute to broadening our comprehension of the virosphere. Extreme environments offer optimal prospects for unearthing novel viruses.”

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Nature generates more data than the internet … for now https://www.popsci.com/science/human-nature-data-comparison/ Fri, 22 Sep 2023 19:00:00 +0000 https://www.popsci.com/?p=573562
Internet data server farm with green and pink glowing LED lights
A data server farm in Frankfurt, Germany. By some estimates, the internet is growing at a rate of 26 percent annually. Sebastian Gollnow/picture alliance via Getty Images

In the next century, the information transmitted over the internet might eclipse the information shared between Earth's most abundant lifeforms.

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Internet data server farm with green and pink glowing LED lights
A data server farm in Frankfurt, Germany. By some estimates, the internet is growing at a rate of 26 percent annually. Sebastian Gollnow/picture alliance via Getty Images

Is Earth primarily a planet of life, a world stewarded by the animals, plants, bacteria, and everything else that lives here? Or, is it a planet dominated by human creations? Certainly, we’ve reshaped our home in many ways—from pumping greenhouse gases into the atmosphere to literally redrawing coastlines. But by one measure, biology wins without a contest.

 In an opinion piece published in the journal Life on August 31, astronomers and astrobiologists estimated the amount of information transmitted by a massive class of organisms and technology for communication. Their results are clear: Earth’s biosphere churns out far more information than the internet has in its 30-year history. “This indicates that, for all the rapid progress achieved by humans, nature is still far more remarkable in terms of its complexity,” says Manasvi Lingam, an astrobiologist at the Florida Institute of Technology and one of the paper’s authors.

[Related: Inside the lab that’s growing mushroom computers]

But that could change in the very near future. Lingam and his colleagues say that, if the internet keeps growing at its current voracious rate, it will eclipse the data that comes out of the biosphere in less than a century. This could help us hone our search for intelligent life on other planets by telling us what type of information we should seek.

To represent information from technology, the authors focused on the amount of data transferred through the internet, which far outweighs any other form of human communication. Each second, the internet carries about 40 terabytes of information. They then compared it to the volume of information flowing through Earth’s biosphere. We might not think of the natural world as a realm of big data, but living things have their own ways of communicating. “To my way of thought, one of the reasons—although not the only one—underpinning the complexity of the biosphere is the massive amount of information flow associated with it,” Lingam says.

Bird calls, whale song, and pheromones are all forms of communication, to be sure. But Lingam and his colleagues focused on the information that individual cells transmit—often in the form of molecules that other cells pick up and respond accordingly, such as producing particular proteins. The authors specifically focused on the 100 octillion single-celled prokaryotes that make up the majority of our planet’s biomass

“That is fairly representative of most life on Earth,” says Andrew Rushby, an astrobiologist at Birkbeck, University of London, who was not an author of the paper. “Just a green slime clinging to the surface of the planet. With a couple of primates running around on it, occasionally.”

Bacteria colony forming red biofilm on black background
This colorized image shows an intricate colony of millions of the single-celled bacterium Pseudomonas aeruginosa that have self-organized into a sticky, mat-like colony called a biofilm, which allows them to cooperate with each other, adapt to changes in their environment, and ensure their survival. Scott Chimileski and Roberto Kolter, Harvard Medical School, Boston

As all of Earth’s prokaryotes signal to each other, according to the authors’ estimate, they generate around a billion times as much data as our technology. But human progress is rapid: According to one estimate, the internet is growing by around 26 percent every year. Under the bold assumption that both these rates hold steady for decades to come, the authors stated its size will continue to balloon until it dwarfs the biosphere in around 90 years’ time, sometime in the early 22nd century.

What, then, does a world where we create more information than nature actually look like? It’s hard to predict for certain. The 2110s version of Earth may be as strange to us as the present Earth would seem to a person from the 1930s. That said, picture alien astronomers in another star system carefully monitoring our planet. Rather than glimpsing a planet teeming with natural life, their first impressions of Earth might be a torrent of digital data.

Now, picture the reverse. For decades, scientists and military experts have sought out signatures of extraterrestrials in whatever form it may take. Astronomers have traditionally focused on the energy that a civilization of intelligent life might use—but earlier this year, one group crunched the numbers to determine if aliens in a nearby star system could pick up the leakage from mobile phone towers. (The answer is probably not, at least with LTE networks and technology like today’s radio telescopes.)

MeerKAT radio telescope dish under starry sky
The MeerKAT radio telescope array in South Africa scans for, among other things, extraterrestrial communication signals from distant stars. MeerKAT

On the flip side, we don’t totally have the observational capabilities to home in on extraterrestrial life yet. “I don’t think there’s any way that we could detect the kind of predictions and findings that [Lingam and his coauthors] have quantified here,” Rushby says. “How can we remotely determine this kind of information capacity, or this information transfer rate? We’re probably not at the stage where we could do that.”

But Rushby thinks the study is an interesting next step in a trend. Astrobiologists—certainly those searching for extraterrestrial life—are increasingly thinking about the types and volume of information that different forms of life carries. “There does seem to be this information ‘revolution,’” he says, “where we’re thinking about life in a slightly different way.” In the end, we might learn that there’s more harmony between the communication networks nature has built and computers.

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Pollen could hold clues to mysteries of early human migration https://www.popsci.com/science/pollen-human-migration/ Fri, 22 Sep 2023 18:00:00 +0000 https://www.popsci.com/?p=573514
Yellow pollen spring out from a coniferous tree. The pollen that makes us sneeze every spring, may have helped lay the groundwork for the migration of our very distant ancestors into Eurasia.
The pollen that makes us sneeze every spring, may have helped lay the groundwork for the migration of our very distant ancestors into Eurasia. Deposit Photos

More tree pollen could have led to more Pleistocene-era people living in Eurasia.

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Yellow pollen spring out from a coniferous tree. The pollen that makes us sneeze every spring, may have helped lay the groundwork for the migration of our very distant ancestors into Eurasia.
The pollen that makes us sneeze every spring, may have helped lay the groundwork for the migration of our very distant ancestors into Eurasia. Deposit Photos

There’s a recurring mystery surrounding early human migration: Exactly when did Homo sapiens make their way from Africa into Europe and Asia? It’s possible that a period of warmer temperatures could have contributed to this flow of people into Eurasia, according to a study published September 22 in the journal Science Advances. Warmer temperatures and more humidity may have helped the forests in the region grow and expand north into present-day Siberia. The theory hinges on the presence of pollen in the region’s sediment record. The scourge of modern day spring allergy sufferers could have laid the groundwork for our very distant ancestors’ migration into Eurasia.  

[Related: Humans and Neanderthals could have lived together even earlier than we thought.]

This movement could have begun in three waves into Eurasia about 54,000 years ago. It is also likely that both warm and cold climates would have played a role in this travel. The Pleistocene Epoch is known for huge climatic shifts, including the formation of the massive ice sheets and glaciers that would eventually forge and shape many of the landforms we see on Earth today. 

To piece together what the climate could have looked like during a possible warm period about 45,000 to 50,000 years ago, researchers working on the study created a record of the vegetation and pollen from the Pleistocene found around Lake Baikal in present-day Siberian region of Russia with the oldest archeological traces of Homo sapiens in the area. 

Sediment cores were used to extract data for a pollen timeline, and the study suggests that the dispersal of humans occurred during some of the highest temperatures and highest humidity of the late Pleistocene. The presence of more ancient pollen, and thus plant life, in the record shows evidence that coniferous forests and grasslands may have spread further throughout the region and could support foraging for food and hunting by humans. According to study author and University of Kansas anthropologist Ted Goebel, the environmental data combined with archeological evidence tell a new story of the area. 

“This contradicts some recent archaeological perspectives in Europe. The key factor here is accurate dating, not just of human fossils and animal bones associated with the archaeology of these people, but also of environmental records, including from pollen,” Goebel said in a statement. “What we have presented is a robust chronology of environmental changes in Lake Baikal during this time period, complemented by a well-dated archaeological record of Homo sapiens’ presence in the region.”

A map of theorized migration routes of early Homo sapiens from Africa across Eurasia. CREDIT: Ted Goebel.
A map of theorized migration routes of early Homo sapiens from Africa across Eurasia. CREDIT: Ted Goebel.

Goebel worked with teams from three institutions in Japan, including Masami Izuho of Tokyo Metropolitan University. During the pollen analysis, the team found some potential connections between the pollen data and the archeological record of early human migration into the region. The early modern humans of this period were making stone tools on slender blands and using bones, antlers, and even ivory to craft the tools. 

“There is one human fossil from Siberia, although not from Lake Baikal but farther west, at a place called Ust’-Ishim,” Goebel said. “Morphologically, it is human, but more importantly, it’s exceptionally well-preserved. It has been directly radiocarbon-dated and has yielded ancient DNA, confirming it as a representative of modern Homo sapiens, distinct from Neanderthals or Denisovans, or other pre-modern archaic humans.”

[Related: World’s oldest known wooden structure pre-dates our species.]

It’s possible that the earliest humans in the area likely would have lived in extended nuclear families, but it is difficult to say with certainty since so much archeological evidence has degraded over time. Ust’-Ishim in Siberia provides the earliest known evidence of fully modern humans coexisting with other extinct human species in the area, but the find was an “isolated discovery,” according to the team.

“We lack information about its archaeological context, whether it was part of a settlement or simply a solitary bone washed downstream,” said Goebel. “Consequently, linking that single individual to the archaeological sites in the Baikal region is tenuous—do they represent the same population? We think so, but definitely need more evidence.”

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These 24-eyed jellyfish learn from their mistakes https://www.popsci.com/environment/jellyfish-learn/ Fri, 22 Sep 2023 15:00:00 +0000 https://www.popsci.com/?p=573449
A Caribbean box jellyfish on a black background. It has a round, bell shaped body, with about 11 visible tentacles. It also has four parallel brain-like structures with roughly 1,000 nerve cells in each.
A Caribbean box jellyfish has four parallel brain-like structures with roughly 1,000 nerve cells in each. Jan Bielecki

Instead of a centralized brain, the Caribbean box jellyfish uses four brain-like structures to thrive the ocean.

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A Caribbean box jellyfish on a black background. It has a round, bell shaped body, with about 11 visible tentacles. It also has four parallel brain-like structures with roughly 1,000 nerve cells in each.
A Caribbean box jellyfish has four parallel brain-like structures with roughly 1,000 nerve cells in each. Jan Bielecki

Jellyfish are an undeniable evolutionary success story, surviving at least 500 million years in Earth’s oceans. They are even poised to handle climate change very well in some areas of the world, all without a centralized brain like most animals. Despite this lack of a central brain, trained Caribbean box jellyfish can potentially remember their past experiences the way that flies, mice, and humans do, and learn to spot and dodge previously encountered obstacles in a tank. The findings are reported in a study published on September 22 in the journal Current Biology.

[Related: Jellyfish may have been roaming the seas for at least 500 million years.]

This species of jellyfish is ubiquitous in the waters of the Caribbean Sea and the central Indo-Pacific Ocean, but are generally just about a half inch in diameter. Box jellyfish like these are members of a class of jellyfish that are known for being among the most poisonous animals in the world and their stings can cause paralysis and even death in extreme cases

To keep up their stinging and navigate their watery world, jellyfish don’t have a centralized brain like most members of the animal kingdom. They have four parallel brain-like structures with roughly 1,000 nerve cells in each. By comparison, a human brain has approximately 100 billion nerve cells. Caribbean box jellyfish are equipped with a complex visual system of 24 eyes embedded into their bell-shaped body. They use this unique vision to steer through the murky waters of mangrove swamps, looking for prey and diving under underwater tree roots. 

“It was once presumed that jellyfish can only manage the simplest forms of learning, including habituation–i.e., the ability to get used to a certain stimulation, such as a constant sound or constant touch,” study co-author and University of Copenhagen neurobiologist Anders Garm said in a statement. “Now, we see that jellyfish have a much more refined ability to learn, and that they can actually learn from their mistakes. And in doing so, modify their behavior.”

In this study, the team used a round tank outfitted with gray and white stripes to mimic the jellyfish’s natural habitat. The gray stripes were mimicking mangrove roots that would appear to be distant at the start of the experiment. For 7.5 minutes, the team observed the jellyfish in the tank. Initially, the jelly swam close to these seemingly far away stripes and bumped into them frequently. However, by the end of the experiment, the jelly increased its average distance to the wall by roughly 50 percent, quadrupled the number of successful pivots to avoid collision with the fake tree, and cut its contact with the wall by half. 

The findings suggest that jellyfish can learn from experience and could acquire the ability to avoid obstacles through a process called associative learning. In this process, organisms form mental connections between sensory stimulations and behaviors

“Learning is the pinnacle [of] performance for nervous systems,” Jan Bielecki, a co-author of the study and a neuroscientist at Kiel University in Germany, said in a statement.

Bielecki added that in order to teach jellyfish a new trick, “it’s best to leverage its natural behaviors, something that makes sense to the animal, so it reaches its full potential.”

[Related: Italian chefs are cooking up a solution to booming jellyfish populations.]

The team then looked into pinpointing the underlying process of jellyfish’s associative learning by isolating the animal’s visual sensory centers called rhopalia. Each rhopalia houses six eyes that control the jellyfish’s pulsing motion. This motion spikes in frequency when the jelly swerves away from an obstacle. 

They showed the stationary rhopalium moving gray bars to mimic how the jelly approaches objects and the rhopalium did not respond to light gray bars, seemingly interpreting the bars as distant. The researchers then trained the rhopalium with some weak electric stimulations that mimicked the mechanical stimuli that occur when colliding with an object. Following the electric stimulation, the rhopalium started to generate obstacle-dodging signals in response to the light gray bars as they got closer. 

The findings from this stage of the experiment showed that combining visual and mechanical stimuli is necessary for associative learning in jellyfish and that the rhopalium is likely serving as the animal’s learning center.

“For fundamental neuroscience, this is pretty big news. It provides a new perspective on what can be done with a simple nervous system,” said Garm. “This suggests that advanced learning may have been one of the most important evolutionary benefits of the nervous system from the very beginning.”

The team plans to do a deeper dive into the cellular interactions of jellyfish nervous systems to tease apart the process of memory formation and also hope to understand how the mechanical sensor in the jellyfish’s body works to paint a more complete picture of its associative learning.

“It’s surprising how fast these animals learn; it’s about the same pace as advanced animals are doing,” says Garm. “Even the simplest nervous system seems to be able to do advanced learning, and this might turn out to be an extremely fundamental cellular mechanism invented at the dawn of the evolution nervous system.”

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Humans might just love French bulldogs because they remind them of babies https://www.popsci.com/environment/french-bulldogs-why/ Thu, 21 Sep 2023 16:00:00 +0000 https://www.popsci.com/?p=573289
A black and white French bulldog puppy sits in a garden with green grass and orange flowers. In an experiment where dogs had to find food hidden in a box, flat-faced dogs were more likely to look back at people than a breed with a mid-length muzzle.
In an experiment where dogs had to find food hidden in a box, flat-faced dogs were more likely to look back at people than a breed with a mid-length muzzle. Deposit Photos

A small study offers clues on why these pooches are so popular, despite their known health issues.

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A black and white French bulldog puppy sits in a garden with green grass and orange flowers. In an experiment where dogs had to find food hidden in a box, flat-faced dogs were more likely to look back at people than a breed with a mid-length muzzle.
In an experiment where dogs had to find food hidden in a box, flat-faced dogs were more likely to look back at people than a breed with a mid-length muzzle. Deposit Photos

Earlier this year, the French bulldog replaced the Labrador retriever as the most popular pet dog in the United States. Flat-faced or brachycephalic dogs continue to be a favorite despite their health problems. These include breathing issues like Brachycephalic Obstructive Airway Syndrome (BOAS), an increased risk of heat stroke, and multiple eye issues stemming from aesthetic-based genetic engineering and extreme breeding. In response to these health issues, the Netherlands has banned their breeding on ethical grounds, and the British Veterinary Association has urged people to not buy flat-faced breeds.

[Related: How breeding dogs for certain traits may have altered their brains.]

Cognitive ethologist and behavior biologist Eötvös Loránd University in Hungary Dorottya Júlia Ujfalussy and her team are working on understanding a “paradox phenomenon,” where the number of these flat faced pets continues to increase, despite their known health and longevity issues.

“One reason for choosing a flat-faced pet may be the child-like appearance, however, owner reports suggest that behavior is also involved. We are trying to pinpoint the behavior traits that set these breeds apart from breeds with more healthy head shapes,” Ujfalussy tells PopSci.

In a small study published September 21 in the journal Scientific Reports, Ujfalussy and her team found that these breeds are more likely to look at humans longer and display traits that appear “helpless” and more infant-like to humans. The team assessed the behavior of 15 English bulldogs and 15 French bulldogs compared to the behavior of 13 Hungarian mudis. Mudis are herding dogs with a mid-length muzzle and do not have the bulldogs’ squished face. 

The dogs had to try and open three boxes to retrieve a piece of food. The boxes had different opening techniques that varied in difficulty and they were presented to all of the dogs in a random order. The dogs also saw one of the researchers put a piece of sausage into a box and were then given two minutes to open the box. The team and dog’s owner stood behind the dog and out of direct sight during the experiment. 

A French bulldog successfully opening a box and retrieving the food. CREDIT: Erzsébet Mőbiusz/Marianna Molnár.
A French bulldog successfully opening a box and retrieving the food. CREDIT: Erzsébet Mőbiusz/Marianna Molnár.

English and French bulldogs successfully opened the box 93 percent less often than the mudis did. The successful mudis were also faster than the bulldogs who opened the boxes. By the time one minute had gone by, roughly 90 percent of mudis had opened the box, compared to about 50 percent of the bulldogs. However, the bulldogs were 4.16 and 4.49 times as likely to look back at their people than mudis.

“The most surprising was the extent of the helplessness, lack of success and visual orientation of dogs to the owners,” Ujfalussy says. “It seemed like they were depending on their humans to solve problems for them much more than your typical family dogs.”

The team believes that these findings show that short-faced dogs seek out humans when faced with problems more frequently, which may promote a stronger social relationship between the owners and their dogs due to this perception of helplessness. 

[Related: Dogs and wolves remember where you hide their food.]

The study could not establish whether flat-faced dogs are actually genetically predisposed to look more dependent on humans than other dog breeds or whether  owners’ attitudes towards flat-faced dogs encourages dependent behavior. The team is working to continue to study these behavior characteristics.

“We would like to raise awareness of this ‘flat-faced’ paradox in the hope that people make more conscious choices of pets, not relying on their instincts and falling for the ‘cute looks’ and dependent (helpless) behavior that reminds them of human children,” says Ujfalussy.

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These parasitic plants force their victims to make them dinner https://www.popsci.com/science/parasitic-plants-force-hosts-to-grow/ Thu, 21 Sep 2023 15:00:00 +0000 https://www.popsci.com/?p=573243
Multiple reddish pink parasitic plants called balanophora growing in a forest. Balanophora shed one third of its genes as it evolved into a very streamlined parasitic plant.
Balanophora shed one third of its genes as it evolved into a very streamlined parasitic plant. Ze Wei/Plant Photo Bank of China/Nature Plants

Two parasitic plants in a new study are losing genes related to photosynthesis and other plant functions as they continue their food-sucking habits.

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Multiple reddish pink parasitic plants called balanophora growing in a forest. Balanophora shed one third of its genes as it evolved into a very streamlined parasitic plant.
Balanophora shed one third of its genes as it evolved into a very streamlined parasitic plant. Ze Wei/Plant Photo Bank of China/Nature Plants

Parasitic plants make up about 1 percent of flowering species within the plant kingdom and their quirks and tricks continue to come with surprises. Some parasitic plants are now potentially evolving to be so dependent on their host plants, that they are losing sizable amounts of genomes related to basic biological processes like photosynthesis. The findings are described in a study published September 21 in the journal Nature Plants.

[Related: How a peculiar parasitic plant relies on a rare Japanese rabbit.]

Plants in the Balanophoraceae family that are found in tropical and temperate regions in Asia and tropical Africa generally resemble fungi growing around the roots of trees in the forest, but there is a lot more than meets the eye. The structures that look like mushrooms are instead inflorescences, or a cluster of flowers intricately arranged on a stem.  

However, unlike other parasitic plants that extend a skinny projection called a haustorium into a host’s tissue to steal its nutrients, plants in the Balanophora genus actually induce their host plant’s vascular system to grow into a tuber to store nutrients. This forms a unique underground organ made from tissue of both the host plant that Balanophora then uses to eat..

To learn more about how these subtropical extreme parasitic plants evolved into this unique form, a team from the Beijing Genomics Institute (BGI) and the University of British Columbia compared Balanophora’s genomes with another parasitic plant genus called Sapria that has a very different vegetative body. Sapria are members of the family Rafflesiaceae, including some very smelly corpse flowers, and can generally be found in tropical forests of Asia.

The study found that Sapria has lost 38 percent of its genomes and Balanophora has lost 28 percent of their genomes over time, while evolving their parasitic behaviors, which the authors say is a record genetic shrinking for flowering plants.

A reddish pink parasitic plant grows from a root system. Balanophora is a parasitic plant found in tropical and temperate regions in Asia and tropical Africa and generally resembles fungi growing around the roots of trees in the forest.
Balanophora is a parasitic plant found in tropical and temperate regions in Asia and tropical Africa and generally resembles fungi growing around the roots of trees in the forest. CREDIT: Xiaoli Chen/BGI Research/Nature Plants.

“The extent of similar, but independent gene losses observed in Balanophora and Sapria is striking,” study co-author and BGI Research plant geneticist Xiaoli Chen said in a statement. “It points to a very strong convergence in the genetic evolution of holoparasitic lineages, despite their outwardly distinct life histories and appearances, and despite their having evolved from different groups of photosynthetic plants.”

They found that both Balanophora and Sapria have even lost almost all of the genes associated with photosynthesis and other key biological processes, including nitrogen absorption, root development, and the regulation of flower development. 

“The majority of the lost genes in Balanophora are probably related to functions essential in green plants, which have become functionally unnecessary in the parasites,” study co-author and University of British Columbia botanist Sean Graham said in a statement.

[Related: We’re finally figuring out how plants pass on genetic memories.]

Since these parasitic plants don’t necessarily need to rely on sunlight and water to make food through photosynthesis and instead use the resources of their host plants, they appear to be losing those genes. 

Notably, the genes related to the synthesis of a major hormone responsible for plant stress responses and signaling called abscisic acid (ABA) have also been lost in Balanophora and Sapria. Even with the loss, the team still recorded a build up of the ABA hormone in Balanophora’s flowering stems and saw that genes involved in the response to ABA signaling are still retained in the parasites. According to the team, this gene loss could be beneficial to the plant. 

“The loss of their entire ABA biosynthesis pathway may be a good example. It may help them to maintain physiological synchronization with the host plants,” said Graham. “This needs to be tested in the future.”

The team says that this study deepens the major genomic alterations occurring within parasitic plants and is important in the context of a project working to sequence the genomes of 10,000 plant species called 10KP.

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As humans get louder, monkeys mark more territory https://www.popsci.com/environment/monkeys-more-smells/ Thu, 21 Sep 2023 12:30:00 +0000 https://www.popsci.com/?p=573006
A pied tamarin monkey sits on a large rope. Pied tamarin monkeys live in a small geographic range in Brazil, where they eat fruits, flowers, and various tree gums and saps.
Pied tamarin monkeys live in a small geographic range in Brazil, where they eat fruits, flowers, and various tree gums and saps. Jacob Dunn/Anglia Ruskin University

Brazil’s pied tamarin monkeys use scent marking and vocal calls to communicate, but it’s getting more difficult for them to hear one another.

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A pied tamarin monkey sits on a large rope. Pied tamarin monkeys live in a small geographic range in Brazil, where they eat fruits, flowers, and various tree gums and saps.
Pied tamarin monkeys live in a small geographic range in Brazil, where they eat fruits, flowers, and various tree gums and saps. Jacob Dunn/Anglia Ruskin University

In an increasingly noisy world, some primates are pushing to be noticed with another sense. A study published September 20 in the journal Ethology Ecology & Evolution found that pied tamarin monkeys use scent markings to communicate more often so they can compensate for noise pollution generated by humans. 

[Related: Noise pollution messes with beluga whales’ travel plans.]

Pied tamarins are 11 to 12 inch long monkeys with furry bodies and bare faces. The species is currently listed as Critically Endangered by the IUCN. They live in a very narrow geographic range in central Brazil. Most of their territory now lies within the city of Manaus, a port city of about 2.6 million residents. The expansion of the city has restricted individual groups of monkeys to small patches that are surrounded by noisy urban spaces. 

Communicating with other groups of monkeys is crucial for their survival, so in addition to long vocal calls, pied tamarins use multiple types of scent markings to send messages. The scent markings have different functions, including passing along territorial and reproductive information. Pied tamarins have special glands above their genitals and near their stomachs that emit these scents that leave behind an olfactory message to other monkeys. This practice is also not unique to pied tamarins. Domestic and wild felines can use their famously pungent spray to mark territory, as do dogs and red pandas to name a few other mammals.

In the new study, a team from the Universidade Federal do Amazonas in Brazil and Anglia Ruskin University in England looked at the behavior of nine separate groups of wild pied tamarins. They followed each group for 10 days using radio tracking and the most common source of anthropogenic noise was road traffic. There was also noise pollution from park visitors, aircraft, and military activity.

The team found that the frequency of scent marking directly increased with decibel levels, which suggests that scent marking is being used more frequently as their vocal communication becomes more drowned out by human noise. 

“Many species depend on acoustic signals to communicate with other members of the same species about essential information such as foraging, mate attraction, predators, and territorial defense,” study co-author and Universidade Federal do Amazonas biologist Tainara Sobroza said in a statement

Their long vocal calls are generally used to mark territory and for communications between members of the group. In Manaus, they are important since the forest landscape is fragmented and urban areas are encroaching on their territory. The authors believe that this increase in scent marking is directly tied to this increase in urbanization. 

[Related from PopSci+: Why your dog needs to smell the world.]

“Humans have contributed many additional stimuli to the soundscapes that animals have evolved to deal with, and anthropogenic noise is increasingly drowning out natural sounds,” study co-author and Anglia Ruskin University behavioral ecologist Jacob Dunn said in a statement. “The increased use of scent marking by pied tamarins is likely to be a flexible response towards this environmental change. This is an interesting result from a conservation perspective as it shows pied tamarins are adapting their behavior in response to city noise.

One of the advantages scent marking has over vocal communication is that the information can be passed on over several days, instead of just after making a call. On the other hand, vocal calls are a better way of communicating over long distances. 

“As the pied tamarins’ range is becoming more fragmented and groups are becoming more isolated, this could potentially have a detrimental impact on a species which is already critically endangered,” said Dunn.

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This parasite deploys mucus slime balls to make ‘zombie ants’ https://www.popsci.com/science/parasite-zombie-ants/ Tue, 19 Sep 2023 15:00:00 +0000 https://www.popsci.com/?p=572374
A dissected ant and where you can see the encapsulated parasites (white oval structures) spilling out of the hind body.
A dissected ant and where you can see the encapsulated parasites (white oval structures) spilling out of the hind body. Brian Lund Fredensborg

A new study finds that lancet liver flukes may be using air temperature to their infection advantage.

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A dissected ant and where you can see the encapsulated parasites (white oval structures) spilling out of the hind body.
A dissected ant and where you can see the encapsulated parasites (white oval structures) spilling out of the hind body. Brian Lund Fredensborg

Just in time for spooky season, scientists have learned more about how a tiny parasitic flatworm called the lancet liver fluke infects and controls the brains of ants. With their complex four-step cycle, the flukes could be cunningly adjusting to daily changes in air temperatures to infect more hosts. The findings were recently published in the journal Behavioral Ecology.

[Related: Mind-controlling ‘zombie’ parasites are real.]

Step 1: The Zombie Ant

The parasite hijacks an ant’s brain after an ant eats a ball of snail mucus infested with fluke larvae. The larvae then mature inside the brain, where the parasite can make the ant climb up a blade of grass and clamp down on the blade. This strategic height makes it easier for the parasite’s next potential host—a cow, sheep, deer, or other grazer—to eat the flukes and offer it another place to live and breed. This new study found that the liver fluke can even get the ant to crawl back down the blade of grass when it gets too hot.

“Getting the ants high up in the grass for when cattle or deer graze during the cool morning and evening hours, and then down again to avoid the sun’s deadly rays, is quite smart. Our discovery reveals a parasite that is more sophisticated than we originally believed it to be,” University of Copenhagen biologist and study co-author Brian Lund Fredensborg said in a statement. Fredensborg conducted the research with his former graduate student Simone Nordstrand Gasque, now a PhD student at Wageningen University in the Netherlands.

In their study, the team tagged several hundred infected ants in the Bidstrup Forests near Roskilde, Denmark. “It took some dexterity to glue colors and numbers onto the rear segments of the ants, but it allowed us to keep track of them for longer periods of time,” said Fredensborg.

The team observed how the infected ants behaved to humidity, light, time of day, and temperature and it was clear that temperature has an effect on their behavior. During cooler temperatures, the ants were more likely to be attached to the top of a blade of grass. When the temperature rose, the ants let go of the grass and crawled back down. 

“We found a clear correlation between temperature and ant behavior,” said Fredensborg. “We joked about having found the ants’ zombie switch,’”

Step 2: The Grazer

Once the liver fluke infects the ant, several hundred parasites invade the insect’s body. Only one of these parasites will make it to the brain where it then influences the ant’s behavior. The remaining liver flukes conceal themselves in the ant’s abdomen inside of its intestine. There, the liver flukes find their way through the bile ducts and into the liver, where they suck blood and develop into adult flukes that begin to lay eggs. 

[Related: ‘Brainwashing’ parasites inherit a strange genetic gap.]

“Here, there can be hundreds of liver flukes waiting for the ant to get them into their next host. They are wrapped in a capsule which protects them from the consequent host’s stomach acid, while the liver fluke that took control of the ant, dies. You could say that it sacrifices itself for the others,” said Fredensborg. 

The eggs are then excreted in the host animal’s feces.

Step 3: The Snail

Once the fluke eggs have been excreted, they remain on the ground waiting for a snail to crawl by and eat the feces. When the eggs are inside the snail, the eggs develop into larval flukes that reproduce asexually and can multiply into several thousand. 

“Historically, parasites have never really been focused on that much, despite there being scientific sources which say that parasitism is the most widespread life form,” said Fredensborg. “This is in part due to the fact that parasites are quite difficult to study.”

Step 4: The Slime Ball

To exit the snail and move on to their next host, the larval flukes make the snail cough. The flukes are then expelled from the snail in a lump of mucus. The ants are attracted to this moist ball, eat it, and unwittingly ingest more fluke larvae and the cycle begins all over again.

The tiny liver fluke is widespread in Denmark and other temperate regions around the world and researchers are still trying to understand more of the mechanisms behind how they take over a host’s brain. 

“We now know that temperature determines when the parasite will take over an ant’s brain. But we still need to figure out which cocktail of chemical substances the parasite uses to turn ants into zombies,” Fredensborg said. “Nevertheless, the hidden world of parasites forms a significant part of biodiversity, and by changing the host’s behavior, they can help determine who eats what in nature. That’s why they’re important for us to understand.”

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World’s oldest living aquarium fish could be 100 years young https://www.popsci.com/science/worlds-oldest-living-aquarium-fish/ Tue, 19 Sep 2023 14:00:00 +0000 https://www.popsci.com/?p=572229
An Australian lungfish named Methuselah swims in a tank at the Steinhart Aquarium. The fish has a flat snout, olive-green scales, and a long torpedo-shaped body.
Australian lungfish like Methuselah are native to only to two river systems in Australia and they can use a single lung to breathe air. Gayle Laird/California Academy of Sciences

New DNA analysis reveals that Methuselah the Australian lungfish is even further along in years than scientists previously believed.

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An Australian lungfish named Methuselah swims in a tank at the Steinhart Aquarium. The fish has a flat snout, olive-green scales, and a long torpedo-shaped body.
Australian lungfish like Methuselah are native to only to two river systems in Australia and they can use a single lung to breathe air. Gayle Laird/California Academy of Sciences

The world’s oldest living aquarium fish is actually even older than scientists initially believed. According to an analysis by the California Academy of Sciences, the Steinhart Aquarium’s beloved Australian lungfish named Methuselah is estimated to be about 92 years old, with a high-estimate of over 100.

[Related: Hogfish ‘see’ using their skin.]

Meet Methuselah

Native only to two river systems in Australia, this type of lungfish can actually breathe air. They use a single lung when the streams they live in are more dry than usual or when the water quality changes, according to the Australian Museum. They typically have olive green, black, or brown scales and a body shaped like a torpedo with a flattened snout. While the species is over 100 million years old, they are listed as Endangered on the IUCN Red List. They are very sensitive to human-caused changes to its habitat, primarily damming, that can increase sediment levels in the water. 

CREDIT: California Academy of Sciences.

Methuselah first arrived at the San Francisco aquarium in 1938, aboard a Matson Navigation Company liner. She has outlived the 231 other fish from Australia and Fiji that arrived with her, back when Franklin D. Roosevelt was in his second term as President of the United States and Back to the Future’s Christopher Llloyd was only a baby. 

In the many decades since, Methuselah has become famous in the area for not only her advanced age, but a seemingly charming personality and a puppy-like love of belly rubs. The knowledge of her age is helpful in the context of a larger study on how to more accurately determine the age of lungfish in the wild and help conservation efforts. She was previously estimated to be about 84 years old.

“Although we know Methuselah came to us in the late 1930s, there was no method for determining her age at that time, so it’s incredibly exciting to get science-based information on her actual age,” Steinhart Aquarium’s Curator of Aquarium Projects Charles Delbeek, said in a statement. “Methuselah is an important ambassador for her species, helping to educate and stoke curiosity in visitors from all over the world. But her impact goes beyond delighting guests at the aquarium: Making our living collection available to researchers across the world helps further our understanding of biodiversity and what species need to survive and thrive.”

[Related: Trumpetfish use other fish as camouflage.]

How scientists determined the age of the oldest living aquarium fish

Estimating ages for ancient and long-lived fish like lungfish is technically challenging and has traditionally relied on more invasive and sometimes lethal methods to determine the age of fishes, including removing scales and examining inner ear bones called otoliths. The new age detection method used to estimate Methuselah’s age only uses a small tissue sample from a fin clip and the team believed that this method can be applied to other threatened species, without impacting threatened populations or the animal’s health.

The DNA analysis for this new estimate was led by Ben Mayne of Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) and David T. Roberts of Australian water authority Seqwater. Their upcoming study included Methuselah, two other lungfish belonging to the California Academy of Sciences (ages 54 and 50), and 30 other lungfish from six institutions in Australia and the United States. It created a catalog of living lungfish with the goal of advancing more accurate DNA-based age clocks for the species native to Australia.  This new analysis also found that she could be as old as 101.

“For the first time since the Australian lungfish’s discovery in 1870, the DNA age clock we developed offers the ability to predict the maximum age of the species,” said Mayne. “Accurately knowing the ages of fish in a population, including the maximum age, is vital for their management. This tells us just how long a species can survive and reproduce in the wild, which is critical for modeling population viability and reproductive potential for a species.”

Their original paper detailing how this age prediction method works was published in June 2021 in the journal Molecular Ecology Resources and offers a description of how threatened fish can be safely aged with DNA methylation methods.

“Methuselah’s age was challenging to calculate as her age is beyond the currently calibrated clock. This means her actual age could conceivably be over 100, placing her in the rare club of fish centenarians. While her age prediction will improve over time, she will always live beyond the calibrated age clock, as no other lungfish we know is older than Methuselah,” said Roberts.

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‘Jet lag’ could be messing with pandas’ natural mating behaviors https://www.popsci.com/environment/giant-pandas-jet-lag/ Mon, 18 Sep 2023 17:00:00 +0000 https://www.popsci.com/?p=571738
A giant panda eats a green plant.
Giant pandas in the wild and captivity show three activity peaks in 24 hours, including one peak during nighttime hours. Deposit Photos

Giant pandas living in zoos outside of their original latitudinal range might be missing out on environmental cues.

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A giant panda eats a green plant.
Giant pandas in the wild and captivity show three activity peaks in 24 hours, including one peak during nighttime hours. Deposit Photos

Jet lag isn’t just an unpleasant side effect of travel for humans. It could also affect the internal circadian clock of captive giant pandas living outside of their natural habitat range in China. A study published September 18 in the journal Frontiers in Psychology found that outdoor cues like changes in temperature and daylight are particularly important for giant pandas. Some problems can arise when their environments and natural body clock don’t match up. 

[Related: Pandas weren’t always bamboo fiends.]

Animals’ internal circadian clocks are generally regulated by cues from the environment and are linked to changes in their behavior and physiology. For humpback whales in the North Atlantic, the decrease in the daylight around the autumnal equinox likely signals that it’s time for the whales to migrate south to their breeding grounds in the Caribbean. Several species of migratory birds use variation in temperature to time their migrations and delaying their departures may help them navigate climate change, but at a cost. 

“Animals, including humans, have evolved rhythms to synchronize their internal environment with the external environment,” University of Stirling PhD student and study co-author Kristine Gandia said in a statement. “When internal clocks are not synchronized with external cues like light and temperature, animals experience adverse effects. In humans, this can range from jet lag to metabolic issues and seasonal affective disorder.” 

For the pandas in this study, those living outside of their latitudinal ranges were observed performing fewer activities than they would in the wild and responding to some human-based cues that only exist in captivity. 

Giant pandas in the wild live highly seasonal lives, where spring is time for migrations to find new shoots of their preferred bamboo. Migration season is also mating season, possibly because finding mates is easier when pandas are all after the same bamboo shoots. Pandas are also a favorite in zoos around the world and their public webcams make them easier to observe. 

In this new study, scientists set out to understand how pandas in zoos are affected by the “jet lag” of living in latitudes they did not evolve in, since important conditions such as daylight and temperature ranges will be different in these areas. According to Gandia, the latitudinal range for giant pandas is between 26 and 42 degrees north and matching latitudes could be between 26 and 42 degrees south, since these latitudes mirror the temperature and lighting conditions further north. Other latitudes will have different amounts of sunlight and varying temperatures, which could alter the panda’s internal clocks and changes to their behaviors, such as, looking for a mate. The study also looked at whether or not anthropogenic cues like regular visits from keepers could also affect their circadian clock. 

The team of 13 observers used webcams to monitor 11 giant pandas born in captivity at six zoos both inside and outside pandas’ natural latitudinal range. Every month for one year, they carried out one day’s worth of hourly focal sampling–watching one animal for a set length of time and recording everything the animal does–to see how their behavior changed across a day and how that changed across a year. The observers noted general activity, sexual behavior, and abnormal behavior.

Daylight and temperature changes were particularly important cues for pandas and were closely associated with general activity in latitudes that matched their natural range in China. Just like their wild counterparts, pandas in captivity showed three peaks of activity over 24 hours, including a peak at night. Sexual behaviors were only displayed by adult pandas during the day, which possibly makes it easier to find mates in the wild.

[Related: The science behind our circadian rhythms, and why time changes mess them up.]

The pandas living outside their home latitude were less active, correlating to the different temperature and daylight cues in these newer latitudes. 

“When giant pandas are housed at higher latitudes—meaning they experience more extreme seasons than they evolved with—this changes their levels of general activity and abnormal behavior,” said Gandia. One of the abnormal behaviors included reacting to zoo-specific cues, such as becoming very active during the early morning. This indicates that the pandas may be anticipating a keeper visiting with fresh food.  

Additionally, the pandas’ abnormal and sexual behaviors fluctuated at similar points. The team believes that this could represent frustration that the pandas can’t mate or migrate in captivity as they would in the wild. The pandas living in mismatched latitudes performed fewer abnormal behaviors related to mating, potentially because they weren’t getting the same environmental cues for sexual behaviors.

“To expand on this research, we would want to incorporate cycles of physiological indicators,” said Gandia. “Importantly, we would want to assess sexual hormones to understand the effects the environment may have on the timing of release. This could help us further understand how to promote successful reproduction for a vulnerable species which is notoriously difficult to breed.”

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Can animals give birth to twins? https://www.popsci.com/environment/can-animals-give-birth-to-twins/ Fri, 15 Sep 2023 22:00:00 +0000 https://www.popsci.com/?p=570710
Some animals, including goats, regularly give birth to two babies at once.
Some animals, including goats, regularly give birth to two babies at once. DepositPhotos

For many animal species it’s the norm to have multiple babies at once.

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Some animals, including goats, regularly give birth to two babies at once.
Some animals, including goats, regularly give birth to two babies at once. DepositPhotos

This article is republished from The Conversation.

Ask any parent—welcoming a new baby to the family is exciting, but it comes with a lot of work. And when the new addition is a pair of babies—twins—parents really have their work cut out for them.

For many animal species it’s the norm to have multiple babies at once. A litter of piglets can be as many as 11 or more!

We are faculty members at Mississippi State University College of Veterinary Medicine. We’ve been present for the births of many puppies and kittens over the years—and the animal moms almost always deliver multiples.

But are all those animal siblings who share the same birthday twins?

Twins are two peas in a pod

Twins are defined as two offspring from the same pregnancy.

They can be identical, which means a single sperm fertilized a single egg that divided into two separate cells that went on to develop into two identical babies. They share the same DNA, and that’s why the two twins are essentially indistinguishable from each other.

Twins can also be fraternal. That’s the outcome when two separate eggs are fertilized individually at the same time. Each twin has its own set of genes from the mother and the father. One can be male and one can be female. Fraternal twins are basically as similar as any set of siblings.

diagram of two sperm fertilizing two eggs yielding two embryos, and one sperm fertilizing one egg that divides into two separate embryos

Fraternal twins originate in two eggs fertilized separately, while identical twins originate in a single fertilized egg that divides to create two embryos. Veronika Zakharova/Science Photo Library via Getty Images

Approximately 3 percent of human pregnancies in the United States produce twins. Most of those are fraternal – approximately one out of every three pairs of twins is identical.

Multiple babies from one animal mom

Each kind of animal has its own standard number of offspring per birth. People tend to know the most about domesticated species that are kept as pets or farm animals.

One study that surveyed the size of over 10,000 litters among purebred dogs found that the average number of puppies varied by the size of the dog breed. Miniature breed dogs—like chihuahuas and toy poodles, generally weighing less than 10 pounds (4.5 kilograms)—averaged 3.5 puppies per litter. Giant breed dogs—like mastiffs and Great Danes, typically over 100 pounds (45 kilograms)—averaged more than seven puppies per litter.

When a litter of dogs, for instance, consists of only two offspring, people tend to refer to the two puppies as twins. Twins are the most common pregnancy outcome in goats, though mom goats can give birth to a single-born kid or larger litters, too. Sheep frequently have twins, but single-born lambs are more common.

Horses, which are pregnant for 11 to 12 months, and cows, which are pregnant for nine to 10 months, tend to have just one foal or calf at a time—but twins may occur. Veterinarians and ranchers have long believed that it would be financially beneficial to encourage the conception of twins in dairy and beef cattle. Basically the farmer would get two calves for the price of one pregnancy.

But twins in cattle may result in birth complications for the cow and undersized calves with reduced survival rates. Similar risks come with twin pregnancies in horses, which tend to lead to both pregnancy complications that may harm the mare and the birth of weak foals.

DNA holds the answer to what kind of twins

So plenty of animals can give birth to twins. A more complicated question is whether two animal babies born together are identical or fraternal twins.

Female dogs and cats ovulate multiple eggs at one time. Fertilization of individual eggs by distinct spermatazoa from a male produces multiple embryos. This process results in puppies or kittens that are fraternal, not identical, even though they may look very much the same.

Biologists believe that identical twins in most animals are very rare. The tricky part is that lots of animal siblings look very, very similar and researchers need to do a DNA test to confirm whether two animals do in fact share all their genes. Only one documented report of identical twin dogs was confirmed by DNA testing. But no one knows for sure how frequently fertilized animal eggs split and grow into identical twin animal babies.

And reproduction is different in various animals. For instance, nine-banded armadillos normally give birth to identical quadruplets. After a mother armadillo releases an egg and it becomes fertilized, it splits into four separate identical cells that develop into identical pups. Its relative, the seven-banded armadillo, can give birth to anywhere from seven to nine identical pups at one time.

There’s still a lot that scientists aren’t sure about when it comes to twins in other species. Since DNA testing is not commonly performed in animals, no one really knows how often identical twins are born. It’s possible—maybe even likely—that identical twins may have been born in some species without anyone’s ever knowing.


Michael Jaffe is an associate professor of small animal surgery at Mississippi State University. Tracy Jaffe is an assistant clinical professor of veterinary medicine at Mississippi State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Why your pet might need a glucose monitor https://www.popsci.com/health/glucose-monitor-pets/ Fri, 15 Sep 2023 18:00:00 +0000 https://www.popsci.com/?p=570547
A beagle running through grass.
About 1 in 300 dogs and cats are diagnosed with diabetes. Depositphotos

Tracking blood sugar could make life easier for pets with diabetes, while helping vets and owners.

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A beagle running through grass.
About 1 in 300 dogs and cats are diagnosed with diabetes. Depositphotos

The small medical sensors known as continuous glucose monitors, or CGMs, were first developed to track the blood sugar levels of people with diabetes. But they have recently expanded to several other uses—they’re not just for humans anymore. Veterinarians are repurposing the devices to monitor their furry patients and help regulate diabetes with medication. 

Diabetes is fairly common in dogs and cats, occurring in about 1 in 300 patients. The biggest problem with this disease in pets isn’t its scale, though, but the burden of care, says Chen Gilor, a veterinarian and diabetes specialist at the University of Florida. Animals with diabetes require daily medication such as insulin, which needs regular monitoring to get the doses right. 

That can be tricky for vets and owners. “The question is, how do you make it easier?” says Gilor, who researches veterinary diabetes and has worked with several pharmaceutical companies that manufacture diabetes products. CGMs, he says, might offer a better alternative.

Traditionally, veterinarians measure blood sugar levels in pets using a technique called glucose curves, in which vets periodically take blood samples over roughly 12 hours and manually plot the data. The labor-intensive tool may not give an accurate picture of typical glucose levels because situations that cause anxiety in pets, like going to the vet, skew blood sugar

“It’s stressful. It’s expensive. And, the biggest problem is: It’s a lot of variability,” says Catharine Scott-Moncrieff, a veterinarian at Purdue University who specializes in small animal endocrinology. Blood sugar varies daily, so it’s difficult for vets to make treatment decisions based on just a few hours of data. Because CGMs measure glucose levels every few minutes, they can give vets a better sense of fluctuations and daily averages. 

[Related: Declawing cats is harmful. Do this instead.]

The monitors consist of two main parts: an electrode coated in enzymes, which is inserted under the skin with a guide needle, and an inch-long sensor, adhered to a shaved patch of skin on a pet’s upper back. Rather than directly reading blood sugar, the electrode measures glucose in interstitial fluid—the liquid surrounding the body’s cells—which slightly lags behind changes in blood. Veterinarians usually place the devices in their office and then send their patients home, where the CGMs collect data, transmitted to a smartphone or monitor via Bluetooth.

The sensors typically last up to two weeks—if they aren’t scratched off before then. (Even if a pet yanks out the device in this way, the electrodes are too thin to cause any harm.) Gilor says that while dogs tend not to mind the devices, cats are less tolerant. More finicky patients may have to wear jackets to prevent this preemptive removal. 

Continuous glucose monitors make it easier for vets and owners to care for pets with diabetes.
Continuous glucose monitors make it easier for vets and owners to care for pets with diabetes. Linda Fleeman/Animal Diabetes Australia

CGMs are most useful initially for determining insulin dosages, especially for newly diagnosed patients, says Scott-Moncrieff. Then, vets can apply a new CGM every few months to check in and see whether adjustments are needed.

Gilor also highlights the efficiency of regulating his patients’ diabetes with the monitors. While it might take months to regulate a dog or cat with glucose curves, he says vets can adjust insulin to the right levels in a matter of weeks when using a CGM. 

Although the devices are becoming common in veterinary practices, animal-specific devices are not currently available on the market. Instead, vets prescribe human CGMs off-label. Abbott’s Freestyle Libre is most popular, says Scott-Moncrieff. Without insurance, the newest version retails at about $75 per sensor. (By comparison, a glucose curve may cost owners well more than $100.)

Several studies of the Freestyle Libre in dogs and cats found the device reliably measured normal and high blood sugar levels, though it showed more variation for animals with low blood sugar. Additional studies are evaluating newer versions of the monitor, which is already in its third generation. “You really have to stay up to date on the technology, because it’s always changing,” says Scott-Moncrieff.

Despite its promise, using this human technology for pets comes with some hurdles. For example, the adhesive isn’t intended for animal skin, so vets often use extra, which can sometimes cause irritation. 

[Related: Should pets wear Halloween costumes? Your furry friend can help you decide.]

One diabetes management company, ALR Technologies, is developing a CGM specifically for cats and dogs. It decided to expand into the animal health space after noticing a lack of tools for veterinarians. “They’re just in such a need for a better way to check blood sugar,” says Joe Stern, who heads ALR’s animal health division.

The device, called GluCurve, uses a pet-friendly adhesive and applicator. Its software, which includes a specialized dose calculator for insulin treatment, is designed to share data across a veterinary practice. GluCurve was soft-launched in January and is now off the market while the company modifies the hardware design. It plans to begin selling the product again in the next few months, according to Stern. 

Monitoring blood sugar with any type of CGM requires involvement from a pet’s owner and veterinarian, and it often falls to vets to teach themselves and their clients how to use the tech. “It can be quite intense for veterinarians to have to manage all this additional information. There’s always a downside to technology,” says Scott-Moncrieff, which in this case is mostly time and education. Fluctuations in blood sugar are normal—but concerned owners might need reassurance. She also emphasizes that it’s important for owners to consult with vets before making any treatment decisions. With that in mind, Scott-Moncrieff says, “it’s really powerful technology.” 

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What songbirds can teach us about being smart https://www.popsci.com/science/intelligence-songbirds-vocal-learning/ Thu, 14 Sep 2023 18:00:00 +0000 https://www.popsci.com/?p=570465
A gray tufted titmouse perches on a scientist's hand.
A songbird called a tufted titmouse, commonly found in eastern North America forests. Mélanie Couture

Behavioral scientists found a relationship between styles of bird learning and problem solving.

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A gray tufted titmouse perches on a scientist's hand.
A songbird called a tufted titmouse, commonly found in eastern North America forests. Mélanie Couture

What does it mean to be intelligent? If it’s defined by having the biggest brain, then sperm whales—whose noggins are a hefty 20 pounds—would be the brightest creatures on Earth. But, more likely, it’s how a brain is wired. Viewed in this way, intelligence is what gives an organism the best chance to survive and thrive in an environment. Language may be one of the best ways to demonstrate that kind of smarts. 

Though all animals can communicate with others, humans are one of the few species to have a spoken language. Using speech, we could share complex ideas, pass knowledge through generations, and create communities. Whether spoken language actually helped us evolve as species into more advanced beings, however, has never really been tested.

“Language allowing humans to be a more advanced species is an assumption that somebody came up with one day without really trying [to prove] it,” says Erich Jarvis, a professor at Rockefeller University who studies the neurobiology of vocal learning. The idea stuck around, but so have other common beliefs that are not really supported with evidence—like the myth that we only use 10 percent of our brains at any point in time, he points out. 

But Jarvis and his colleagues were able to examine this hypothesis with the help of songbirds. Jarvis’ new study, published today in Science, provides some of the first evidence that vocal learning—one of the crucial components for a spoken language—is associated with problem-solving. Vocal learning is the ability to produce new sounds by imitating others, relying on experience rather than instinct. Birds who could do this and solve problems had bigger brain sizes, the research team found.

“Learning new sequences of sounds helps to successfully communicate with others and is often useful when you’re going to meet new members of your species that you haven’t met before,” explains Michael Goldstein, a professor of psychology at Cornell University who studies vocal learning in songbirds and humans but was not involved in the study. Vocal learning is most prominent in human infants who, in their first year of life, learn to break up the continuous speech they hear from adults into individual units of sound. Over time, the mimicry of sounds helps babies piece together words and eventually lets them build sentences, Goldstein says.

To get a better grasp of vocal learning and cognition, the study authors turned to songbirds. The majority of species in this avian suborder possess the vocal learning ability. They thrive on every continent except Antarctica. “Of all the bird species in the world, songbirds make up half that number,” explains Jarvis. “It seems like once vocal learning evolved, there was a lot of speciation and diversity.” 

The team performed seven cognitive experiments on 214 songbirds from 23 different species. Of these, 21 species were caught from the wild in New York. Two songbirds studied, zebra finches and canaries, are domesticated. The behavioral tests examined the birds’ problem solving, for instance by figuring out how to remove an object to access the food reward. The researchers also gauged two other skills often associated with intelligence: learning by association, plus what’s called reversal learning, in which an animal adjusts its behavior to get a reward.. They then looked at whether being vocal learners helped develop the three skills, comparing 21 bird species to two others, which were vocal non-learners (these birds learned sounds only during a brief developmental period).

[Related: What does brain size have to do with intelligence?]

The biologists noticed a strong relationship between vocal learning and problem-solving skills. Vocal learning bird species could come up with innovative ideas, such as getting seeds or a worm trapped under a cup by removing the obstacle, piercing it, or pulling it apart. “It’s pretty surprising that these two skills are related to intelligence but not the other traits we measured,” explains Jean-Nicolas Audet, an ecologist and neurobiologist at Rockefeller University who served as the lead study author. All three abilities—problem solving, associative learning, and reversal learning—are typically considered “components of intelligence,” he says.

This doesn’t mean that the two bird species who were not vocal learners were stupid. Instead, it shows they did not evolve this one particular form of intelligence. “We have to be careful and very specific when we talk about intelligence because it really depends on which traits we are talking about,” Audet explains.

[Related: Wild birds don’t need your backyard feeders to survive]

Brain size was another benefit to vocal learning that may have supported these problem-solving abilities. The 21 vocal-learning species had slightly larger brains, relative to their body size, than the two who weren’t. Jarvis says it’s possible these big-noggined birds packed more neurons. Or perhaps they evolved to have larger skull space, which gave rise to extra circuits for more advanced vocal learning and problem-solving skills. “This suggests to me that there’s something special about problem solving,” he says. “Like spoken language, it made some species more advanced than others.”

One question left unanswered is why there’s such a strong relationship between problem-solving abilities and vocal learning. The brain areas in charge of vocal learning are not the same ones that get activated when we need to troubleshoot an issue, says Audet. The next step for this team is to take a deeper look into the brains of songbirds and figure out what genes or other brain regions connect these two areas. Some bridge yet undiscovered helps form this type of intelligence.

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We still don’t know how animals evolved to fly https://www.popsci.com/science/how-did-dinosaurs-evolve-to-fly/ Thu, 14 Sep 2023 13:00:00 +0000 https://www.popsci.com/?p=568193
Microraptor wearing helmet is shot out of a circus cannon to represent how dinosaurs evolved to fly. Illustration in red, yellow, blue, and green.
Feathered dinosaurs like Microraptor probably shot for the skies over and over. María Jesús Contreras for Popular Science

Which came first: the flying dinosaur or the bird?

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Microraptor wearing helmet is shot out of a circus cannon to represent how dinosaurs evolved to fly. Illustration in red, yellow, blue, and green.
Feathered dinosaurs like Microraptor probably shot for the skies over and over. María Jesús Contreras for Popular Science

Dinosaur Mysteries digs into the secretive side of the “terrible lizards” and all the questions that keep paleontologists up at night.

WE STILL LIVE in an age of dinosaurs. Pigeons, penguins, and partridges are all members of the only lineage to survive the asteroid-driven disaster of 66 million years ago. The realization that at least some dinosaurs still flock among us has given a greater depth to paleontology than the field’s founders could have imagined. What we learn about living dinosaurs can help us better understand the species we can touch only as fossils. But even though we can trace the origins of birds from their Velociraptor-like ancestors, there’s one critical part of the story that we don’t fully understand. How on earth did dinosaurs such as Microraptor evolve the ability to fly?

The definition of flight can be a little tricky—it’s not simply about moving through the air. After all, there are marsupials, frogs, snakes, and other animals capable of gliding for impressive distances. Flight is something more specific, requiring the evolution of not only wings but a wing stroke. Watch a raven flap by and you’re watching a dinosaur demonstrate the exact mechanics of keeping itself aloft with one wingbeat after another. The question paleontologists face is how dinosaurs went from terrestrial reptiles scurrying over the ground to feathery, fluttering wonders.

Archaeopteryx lithographica, the earliest recognized bird at about 150 million years old, is of limited help. When the fossil was uncovered in the late 19th century, the splash of feathers found around the Jurassic dinosaur’s bones were quickly taken as an indication that its kind soared over the forests of prehistoric Bavaria. Over time, however, the genus Archaeopteryx started to look more awkward than aerodynamic. The avian ancestor had asymmetrical flight feathers with a shallow leading edge, a critical adaptation for powered flight—but its skeletal anatomy didn’t look capable of flight the way we see it in living birds. The contradiction led to a longstanding debate over whether Archaeopteryx actively flapped into the air, primarily glided, or perhaps even used a different flight stroke from its modern relatives. Whatever the answer, the solution to the mystery can’t be found in its bones alone. And as further feathery dinosaur species have been uncovered, the caper has only grown more complex.

Since the mid-1990s, paleontologists have uncovered dozens of feathery dinosaurs. Many of them are close relatives of Mesozoic birds or otherwise have adaptations related to flight, including the genus Microraptor, which had long feathers on its legs as well as its long arms. In fact, paleontologists think powered flight evolved at least three times among dinosaurs: once among birds and twice among their close dinosaur relatives such as Rahonavis ostromi. That’s not counting the number of feathery species whose anatomy made them more aerodynamically adept than others, but that still weren’t quite capable of keeping themselves aloft by flapping. Instead of a neat, orderly pattern of flight-related traits among birds and their ancestors, the emerging picture shows a tangled mess.

That changes the entire backstory of flying beasts. Up until recently, feathery dinosaurs were cast as representatives of stages in the evolution of flight. Now paleontologists have to figure out how they evolved flight independently multiple times among both birds and feathery nonavian dinosaurs. The path the ancestors of Archaeopteryx took might not be the same as the path taken by predecessors of Microraptor or Rahonavis.

Experts have tossed plenty of ideas about the origins of flight against the proverbial wall. These are broadly divided into “ground-up” and “trees-down” hypotheses, with most paleontologists favoring explanations that focus on how a ground-dwelling, Velociraptor-esque avian ancestor could evolve the ability to fly. Maybe feathery bird ancestors chased insects, leaping after them and trying to trap them with their arm feathers, which would favor dinosaurs able to stay in the air longer. Or maybe flight started with gliding and dinosaurs climbing trees to swoop through the forest, which would give an advantage to those that could flap their arms to soar just a little farther. The behavior of modern birds has provided some clues too, like the way chukar partridges flap their wings to better stabilize themselves while running up inclines.

Every hypothesis about how airborne dinosaurs evolved focuses on the behavior of animals we can’t observe in life. Experts have to draw out what clues they can from feathers, bones, the universal mechanics of flight, and how birds today manage to get into the air and stay there. While it’s possible to conduct wind-tunnel experiments based on skeletal mechanics and other inferred details to calculate how an Archaeopteryx would have fared while flying, there will always be a difference between what a prehistoric species could have done and how it actually behaved back in the Mesozoic. Evolution is not a tidy progression towards a particular outcome, but a story of constant change full of repeats, dead ends, and diversity.

There can’t be a single solution to the puzzle of how dinosaurs evolved to fly because scientists have more than one case to consider. Whether it consists of birds or nonavian dinosaurs, the history of each lineage has to be studied on its own terms. More than that, what seemed like a basic question about the first flying dinosaurs only creates more questions about what led different dinosaurs in different places and times, many miles and millions of years apart, to evolve similar abilities. Pterosaurs—fuzzy, flying reptiles that were related to dinosaurs—reigned over the skies more than 50 million years before Archaeopteryx, so it’s not as if Earth weren’t already full of fliers before dinosaurs caught on. The stories we now deduce of how flying dinosaurs gained their astonishing ability are far more complex than the ones we had even 20 years ago. When you see a house finch alight on a feeder or a turkey vulture slowly turn over a thermal, you’re catching a glimpse of one of the greatest secrets still cached in the fossil record.

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Virgin Galactic’s latest cargo? Ancient human bones https://www.popsci.com/science/virgin-galactic-human-bones/ Tue, 12 Sep 2023 14:00:00 +0000 https://www.popsci.com/?p=569610
Virgin Galactic spacecraft in suborbital flight above Earth
One passenger traveled with fossils of both Australopithecus sediba and Homo naledi. Virgin Galactic

A clavicle and thumb bone from two of humanity's oldest relatives traveled into suborbital space on a tourist trip last week.

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Virgin Galactic spacecraft in suborbital flight above Earth
One passenger traveled with fossils of both Australopithecus sediba and Homo naledi. Virgin Galactic

Space tourism is already becoming so commonplace that Virgin Galactic’s second private astronaut flight on September 8 went off without much fanfare. And although a brief press announcement only announced the names of its three-man passenger list after the trip, the recap didn’t mention Galactic 03’s historic “first” cargo—fossilized bones from two of humanity’s closest ancestors.

According to Tim Nash’s Virgin Galactic biography, the “entrepreneur, adventurer, conservationist and member of the Hubbard Council of The National Geographic Society,” carried with him the clavicle of a nearly 2-million-year-old Australopithecus sediba, as well as a roughly 250,000-year-old thumb bone from Homo naledi. Both hominid remains were previously discovered within the Cradle of Humankind UNESCO World Heritage Site outside Johannesburg, South Africa—sebedi is considered one of the potential candidates that presaged humanity’s Homo genus.

The initiative’s organizers, including researchers at the University of Witwatersrand, Johnnesburg, intended the gesture to represent “humankind’s appreciation of the contribution of all of humanity’s ancestors and our ancient relatives,” said Lee Berger, a National Geographic Explorer in Residence, Carnegie Fellow and Director of the Centre for the Exploration of the Deep Human Journey. “Without their invention of technologies such as fire and tools, and their contribution to the evolution of the contemporary human mind, such extraordinary endeavors as spaceflight would not have happened.”

[Related: Virgin Galactic’s second commercial flight sent three tourists to space’s edge.]

Berger’s son, Matthew, discovered the sebida clavicle in 2008 when he was 9 years old during an expedition alongside his father within the Cradle of Humankind heritage site. Matthew Berger traveled last week to Virgin Galactic’s Spaceport America in New Mexico to hand deliver the bones to Nash, a conservationist involved with human origins research. Caretakers stored both bone fragments within a carbon fiber container prior to their suborbital excursion.

“These fossils represent individuals who lived and died hundreds of thousands of years ago, yet were individuals who likely gazed up at the stars in wonder, much as we do,” Berger said in a September 8 statement via the University of Witwatersrand.

“The magnitude of being among the first civilians going into space, and carrying these precious fossils, has taken a while to sink in, during all of the preparations for the flight,” Nash said via the University of Witwatersrand statement, “But I am humbled and honored to represent South Africa and all of humankind, as I carry these precious representations of our collective ancestors, on this first journey of our ancient relatives into space.”

Nash, alongside Las Vegas real estate entrepreneur Ken Baxter and British engineer and racecar company founder Adrian Reynald, purchased their Virgin Galactic seats as far back as 2004 from company founder and multibillionaire Richard Branson. Tickets for the few minutes’ worth of suborbital weightlessness alongside views of the Earth’s curvature reportedly cost between $250,000 and $450,000.

“We sincerely hope it brings further awareness of the importance of our country and the African continent to understanding the journey of humankind that has led to this historic moment where commercial spaceflight is possible,” says Cradle of Humankind World Heritage Site CEO Matthew Sathekge said via University of Witwatersrand’s announcement.

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These crow relatives put food over friendship https://www.popsci.com/science/jackdaw-social-family-food/ Mon, 11 Sep 2023 14:00:00 +0000 https://www.popsci.com/?p=569128
two jackdaws (Corvus monedula) on a branch
Crows have clique dynamics too. Deposit Photos

In an experiment, jackdaws ditched 'friends' but not family.

The post These crow relatives put food over friendship appeared first on Popular Science.

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two jackdaws (Corvus monedula) on a branch
Crows have clique dynamics too. Deposit Photos

The lives of corvid, or the family of birds that include crows, are shockingly complex. They hold ‘monogamish’ relationships, build tools, hold funerals, solve puzzles, and may even have their own form of democracy. Now, researchers have provided the latest peek into corvid life that adds a new element to their intricate and complicated lives—social climbing. Yes, even birds will ditch their old friends if something better comes along, according to a new study published September 11 in Nature.

For their recent experiment, scientists at universities of Exeter and Bristol utilized the Cornish Jackdaw Project to split a group of jackdaws, members of the crow family found in Europe, western Asia and North Africa, into two randomly sorted groups—A and B. They then tagged the birds with transponder chips, worn like little anklets, to tell who was who. 

[Related: Crows and ravens flexed smarts and strength for world dominance.]

As many animal studies go, there’s got to be some kind of snack involved. This time, the scientists set up a feeding source with two locked doors—one filled with grain, a merely okay morsel for a hungry crow, and the other with a much yummier rendition of some grain and some dried mealworms. If a bird visited alone, only the low-quality snack door opened. With a buddy from the same-tagged group, say two As or two Bs, either both doors unlocked or just the high-quality snack door. But when a jackdaw visited the snack dispenser with a member of the opposite-tagged clique, there were no goodies for anybody.

The choice for the birds then was either loyalty or tasty treats. 

“The jackdaws turned out to be very strategic, quickly learning to hang out with members of their own group and ditching old ‘friends’ from the other group so they could get the best rewards,” author Alex Thornton, a professor of cognitive evolution at Exeter, said in a release.

The same couldn’t always be said for familial relationships. Despite the potentially disappointing outcome, jackdaws would still stick with their offspring, siblings, or mating partners. Some long-term relationships, it turns out, were more important to the feathery creatures than a chance at a delicious morsel. 

“The fundamental idea is that if you need to keep track of interactions you have had with other individuals, remember the outcomes of those interactions and use those to adjust your [behavior],” Thornton told the Guardian. “What we were able to do here was test the idea: can individuals keep track of the outcomes of past interactions and update their relationships. It turns out they can.”

For the authors, these results can give us clues to the evolution of intelligence, memory, and social status in the animal kingdom—and even in the human world. 

“Our findings also help us to understand how societies emerge from individual decisions,” author and Exeter PhD student Josh Arbon said in a release. “The balance between strategically playing the field for short-term benefits and investing in valuable long-term partners ultimately shapes the structure of animal societies, including our own.”

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New series offers an intimate look into how climate change impacts the lives of wildlife https://www.popsci.com/environment/animals-up-close-bertie-gregory/ Mon, 11 Sep 2023 12:00:00 +0000 https://www.popsci.com/?p=568557
An orca whale swims around an ice flow with a crabeater seal and penguin on the ice.
An orca whale swims around an ice flow with a crabeater seal and penguin on the ice. National Geographic for Disney+/Leigh Hickmott

Catch an exclusive clip of orca whales before Animals Up Close with Bertie Gregory premieres on September 13.

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An orca whale swims around an ice flow with a crabeater seal and penguin on the ice.
An orca whale swims around an ice flow with a crabeater seal and penguin on the ice. National Geographic for Disney+/Leigh Hickmott

Climate change is often in the form of extremes in weather like sweltering heat domes, devastating inland flooding or record breaking wildfire seasons, which puts lives and livelihoods at risk for humans. However, the world’s animals who are on the front lines of an ever changing planet experience these changes a little differently. 

[Related: We don’t have a full picture of the planet’s shrinking biodiversity. Here’s why.]

“When we see climate change in the news, we often think of big storms or major weather events but animals are vulnerable to the smallest changes,” wildlife filmmaker and host Bertie Gregory tells PopSci

In the new series “Animals Up Close with Bertie Gregory,” viewers can get a look into these subtleties and changes. In one episode, the team is searching a dive spot in Indonesia for the elusive devil ray, when a swarm of hundreds of jellyfish approaches.

“Avoiding their stingers was like playing a video game! We were told that huge jellyfish plumes like that were becoming a more regular sight in these tropical waters, which is not a good sign,” Gregory says. 

When Gregory checked the dive thermometer, it read 87.8 degrees Fahrenheit, in water that should have been about 82 degrees. A few degrees might not always sound like much, but has an outsized impact on animals.  “Jellyfish are thought to tolerate climate change better than other species, hence their huge numbers on that day. For us, it meant no other signs of life,” says Gregory.

[Related: Maine’s puffins show another year of remarkable resiliency.]

The series spans the planet and uses high-tech drones and cameras that Gregory calls a “game changer” for wildlife filmmaking. The tech allows the filmmakers to catch a glimpse of the outer lives of animals and even some of their more inner workings.

“We also used a military grade thermal imaging camera to film elephants at night in the depth of the jungle in the Central African Republic—it uses heat to “see” in the dark and elephant ears look incredible as you can see all their veins!” says Gregory.

The series also captures just how difficult it is for terrestrial animals like the pumas of Patagonia and marine mammals like Antarctica’s orca whales to get a solid meal and how climate change continues to threaten vital food sources. 

An episode features a group of Antarctic orcas known as the B1s during what Gregory says was the warmest Antarctic trip he has ever experienced. These killer whales are known for a unique strategy to hunt seals resting on the ice that might remind some orca enthusiasts of the hydroplaning killer whales near Argentina’s Valdés peninsula who thrust their 8,000 to 16,000 pound bodies up onto the beach to catch seals. 

Bertie records the sounds made by killer whales as they echolocate. He explains how scientists believe that this is a way that their navigation is perfectly coordinated. CREDIT: National Geographic for Disney+.

Instead of using surf, sand, and rocks like their Argentinian cousins, these Antarctic killer whales work together as a team to create waves that wash the seals into the water. 

“We witnessed and filmed the staggering intelligence and adaptability of a group of killer whales. There are thought to be just 100 of these unique killer whales in existence, and during filming it was clear they were struggling to ‘wave wash’ seals from ice because there wasn’t much ice,” says Gregory.

[Related: Orcas are attacking boats. But is it revenge or trauma?]

The whales had to constantly adapt their strategy just to get a single seal, sometimes risking an escape from their prey in order to teach the younger whales strategies to carry on to the next generation. 

These constant struggles offer up sobering reminders of the macro and micro ways that the planet is changing and making life more difficult for almost every living thing.. Over one million animal and plant species are threatened with extinction, a rate of loss that is 1,000 times greater than previously expected. The  United Nations agreed upon a biodiversity treaty at the end of 2022 pledging to protect 30 percent of the Earth’s wild land and oceans by 2030. Currently, only about 17 percent of terrestrial and 10 percent of marine areas are protected through legislation.

Bumphead parrot fish. CREDIT: National Geographic for Disney+/Bertie Gregory
A bumphead parrot fish. CREDIT: National Geographic for Disney+/Bertie Gregory

The same location in Indonesia where Gregory and his team encountered the stingy jellyfish swarm is home to the Misool Marine Reserve. Despite climate change’s constant challenges, the area is a conservation success story thanks to community-led initiatives to protect the area from overfishing by implementing specific parts where fishing is allowed.

“Now, Misool is one of the few places on earth where biodiversity is increasing. What they’ve managed to do could be a blueprint for how we can protect oceans around the world and proof that if given the chance, nature can make an amazing comeback,” says Gregory. “It’s good news for wildlife and good news for people.”

“Animals Up Close with Bertie Gregory” premieres September 13 on Disney+.

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How an internet sleuth rekindled hope for the survival of the clown wedgefish https://www.popsci.com/environment/clown-wedgefish-extinction-internet/ Fri, 08 Sep 2023 22:00:00 +0000 https://www.popsci.com/?p=568809
How do you find an elusive animal that most people have never even seen dead in a fish market? Matthew McDavitt, above, knows how.
How do you find an elusive animal that most people have never even seen dead in a fish market? Matthew McDavitt, above, knows how. Photo by Melody Robbins

Scientists were writing an obituary for this species when a lawyer found evidence of its existence in an unlikely place.

The post How an internet sleuth rekindled hope for the survival of the clown wedgefish appeared first on Popular Science.

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How do you find an elusive animal that most people have never even seen dead in a fish market? Matthew McDavitt, above, knows how.
How do you find an elusive animal that most people have never even seen dead in a fish market? Matthew McDavitt, above, knows how. Photo by Melody Robbins

This article was originally featured on Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com.

Peter Kyne sits down at his desk to write a eulogy for a fish he’s never met. It’s summer 2019. No scientist has seen signs of the critically endangered Rhynchobatus cooki, or clown wedgefish, since a dead one turned up at a fish market in 1996. Kyne, a conservation biologist at Charles Darwin University in Australia who studies wedgefish, has worked only with preserved specimens of the spotted sea creature. “This thing’s dust,” Kyne thinks, feeling defeated as he writes the somber news in a draft assessment of the global conservation status of wedgefish species for the International Union for Conservation of Nature.

Wedgefish are a type of ray. They look like sharks that swam head first into a panini press, with flat faces and sharkish tails. The clown wedgefish is the runt of the 11 known species, about as long as a baseball bat. Along with their cousins, sawfish and guitarfish, wedgefish are among the most endangered animals in the sea, thanks largely to fishers who supply the shark fin trade. Fetching up to US $1,000 per kilogram, wedgefish’s spiny fin meat is some of the most highly sought in this ecocidal economy because it’s perfect for shark fin soup, a delicacy favored by wealthy East Asian seafood connoisseurs.

Wedgefish’s pointy snouts are easily snagged in fishing nets, so they’re also a frequent, unintended casualty of other commercial fisheries. This double whammy has led to the near eradication of wedgefish worldwide. Nine species are critically endangered. Kyne is about to add an extinction to that list.

Fish photo
Peter Kyne, a conservation biologist at Charles Darwin University in Australia, thought the clown wedgefish was extinct, until Matthew McDavitt presented evidence to the contrary. Photo courtesy of Charles Darwin University

Just hours before submitting the final assessment, though, Kyne learns that a dead clown wedgefish has just shown up at a Singapore fish market. Relieved, he and his colleagues revise their work. But the swift action necessary to help the species won’t be possible without more information. The scientists don’t even know the critter’s habitat requirements. Somehow, they must find out where the last holdouts live.

Kyne mentions the problem in a Zoom meeting about wedgefish conservation. Luckily for Kyne, his friend Matthew McDavitt is among the attendees. McDavitt is an amateur academic well versed in an emerging research methodology that turns the virtual sea of social media posts into information scientists can use to track the world’s rarest species. His curiosity ignited, McDavitt gets to work. Kyne doesn’t know it yet, but the hunt for the clown wedgefish is on.


Matthew McDavitt happens to be an expert on wedgefish and their relatives, but he’s no scientist. He grew obsessed with sawfish as a kid, when the ray’s long, toothy snout hooked his curiosity. At university, McDavitt studied archaeology and became fascinated with ancient cultural ties to sawfish when he learned the Aztecs buried sawfish snouts under their temples and rendered the fish’s likeness in paintings.

After graduating, he wanted to study the sawfish’s importance to other cultures around the world. But sawfish-adjacent ethnozoologist jobs weren’t exactly falling from the sky, so McDavitt pivoted to a legal career. He earned his law degree and became a research attorney, ghostwriting trial briefs and law articles for other attorneys, judges, and mediators, but he never gave up his passion. He started obsessing over guitarfish and wedgefish, too, cramming his marine studies into what little free time he had, sometimes unable to touch them for months. “I do it on breaks. I put in the time when I can,” he says. “I do it on weekends sometimes.”

Fish photo
McDavitt, a lawyer, studied archaeology as an undergraduate and became enamored with the cultural ties ancient civilizations had to sawfish and eventually that enthusiasm extended to guitarfish and wedgefish. Photo by Melody Robbins.

In the early 2000s, as the internet gained traction and social media began its rise, McDavitt mined a treasure trove of information about wedgefish and sawfish—fishing-trip photos, sightings, ancient art, whatever he could find. Over two decades, he compiled thousands of pictures and posts about various species and stored them on his computer.

At first, McDavitt served only his own curiosity about different cultures’ connections to his favorite fish. But along the way, as he contacted ecologists who studied sharks and rays to ask questions and share his findings, he discovered species in locations where they hadn’t been formally recorded before. In some cases, he found what his new ecologist friends suspected were entirely new species. “I’ll often get into work and there, in my inbox, there’s something else he’s found,” says Kyne, who met McDavitt at a sawfish conservation workshop. “I’m like, Matt, how do you do this?” McDavitt began to realize his ethnozoological research could be used to study and protect imperiled marine animals.

McDavitt was practicing what is now known as iEcology, which relies on online public data sources to study the natural world. Scientists can download thousands of records of the species they’re studying without setting foot in the field. “It’s a huge amount of data,” says Ivan Jarić, a professor at Université Paris-Saclay in France and one of iEcology’s most devout advocates. “It is, in many cases, freely available, so it’s easy and cheap to obtain it.”

Many social media posts come tagged with dates and locations, allowing scientists to track animals through space and time to study movement patterns, interspecies behavior, and the abundance and spread of invasive or endangered species. One study used pictures and videos from Italian tourists to track blue sharks along the Mediterranean coast over a decade. Another used Facebook and Instagram posts to count whales on their annual migrations along the coast of Portugal. Scientists in Hawai‘i have used tourist photos to monitor critically endangered Hawaiian monk seal populations.

Fish photo
The COVID-19 pandemic slowed down field studies, but scientists took advantage of various internet platforms where they could find pictures of wedgefish. Photo by Melody Robbins.

iEcology’s origins trace back to at least 2011, but the method began to gain traction in the past several years, as Jarić and other scientists proselytized its advantages. It got another boost in 2020, when the pandemic scuttled fieldwork for many scientists, as iEcology offered them a remote way to continue their research. “It basically saved two years of my career,” says Valerio Sbragaglia, a behavioral ecologist at the Spanish National Research Council’s Institute of Marine Science, who spent the COVID-19 lockdown using amateur angler videos to monitor the spread of an invasive grouper species as it pushed north through a warming Mediterranean Sea.

There are other advantages, too. Field studies can be a constant game of catch-up, where data may become outdated before ecologists can publish their analyses. But iEcology allows them to monitor animals in near real time. These tools also make ecological surveys more accessible to scientists who can’t secure funding for expensive field trips. In Brazil, for instance, researchers used YouTube videos to find examples of people releasing pet fish into wild waterways, where they multiplied and became invasive. “For a developing country,” Sbragaglia says, “it’s a first source of information that can support future research.”

McDavitt’s iEcology skills have earned him a reputation among marine ecologists as a sort of super citizen scientist. His research has been cited in scientific papers detailing the illegal shark fin trade, and he has published his own research on the importance of sawfish to Indigenous peoples in Australia. McDavitt’s work was cited numerous times in a 2007 proposal that convinced the governing body behind the Convention on International Trade in Endangered Species of Wild Fauna and Flora, or CITES, to restrict the trade of seven species of endangered sawfish. “I’m good at finding weird things,” he says.


McDavitt begins his search for the clown wedgefish shortly after his 2019 Zoom meeting with Kyne. The first thing he does is create a methodology for sifting through social media posts. The known clown wedgefish sightings are all at fish markets in either Jakarta or Singapore. McDavitt figures the creatures must live somewhere between the two places, a vast stretch of sea dotted with thousands of islands, occupied by millions of people.

With this in mind, McDavitt compiles a list of about 25 common names for wedgefish from the local Indonesian, Chinese, and Malay dialects spoken across the western Indonesian archipelago. He targets the islands lining the coasts of Sumatra and Borneo, sometimes narrowing his queries to individual towns and villages he finds on Google Maps. His searches produce thousands of posts, many by local subsistence fishers showing off their catches. Dozens include wedgefish, but they’re all the wrong species. “I’m just going through picture after picture after picture, and most of it is, of course, not useful to me,” McDavitt says.

Fish photo
Hours of pouring over data gleaned from the internet eventually revealed the location of clown wedgefish, somewhere between Sumatra, Singapore, and Borneo. Photo by Melody Robbins.

In August, several weeks after Kyne almost wrote off the clown wedgefish, McDavitt hunches over a desk buried in teetering piles of legal paperwork, scrolling through Facebook posts. He pauses on yet another wedgefish photo. “It looked weird,” McDavitt says. The picture, from a 2015 post, shows a somber young Indonesian man hefting a small, flat fish. The white-edged fins and playful polka dots are unmistakable. McDavitt has found the clown wedgefish.

He jumps up from his desk and shouts for his wife. Then he emails Kyne, who has no idea what his friend has been up to until he receives the message. “If it was in the morning, I would’ve had coffee. If it was late at night, I would’ve had red wine. In either case, I probably did spit some out,” Kyne remembers.

The photo comes from Lingga Island, part of a cluster of islands wedged between Sumatra, Singapore, and Borneo. Kyne hurries to apply for grants to fund a full field study of the area. McDavitt keeps combing the web. Over the next few months, he finds five more photos of clown wedgefish from local fishers; some pictures are only a few weeks old. He and Kyne map their findings, establishing for the first time in Western science the clown wedgefish’s range, and publish their work in 2020.

Kyne also taps Charles Darwin University PhD candidate Benaya Meitasari Simeon, who’s spent years researching other wedgefish species, to spearhead the study’s local initiatives. Simeon grew up eating wedgefish, a traditional Indonesian food. Now she’s vowed to protect them; she even sports a wedgefish tattoo on one arm. Simeon musters a team of students and locals to hang illustrated wedgefish guides—scientific wanted posters—in areas where the fish has shown up on Facebook, to help local fishers identify clown wedgefish in their catch and report sightings.

Fish photo
Images of the clown wedgefish are about as scarce as the fish itself. Two animals on the left are clown wedgefish, and three on the right are broadnose wedgefish. Photo courtesy of Matthew McDavitt.

A big part of Simeon’s job is convincing locals to participate in the project. Some are wary of conservationists because they fear new fishing restrictions could harm their livelihoods. The key, Simeon says, is explaining to fishers that “if it’s gone, it’s gone forever and your kids cannot see it anymore.” Her efforts pay off: her network reports around 10 clown wedgefish catches. All are dead.

In early 2023, Simeon travels from her home in Jakarta to a Sumatran hotel room where her colleagues have a juvenile clown wedgefish for her to inspect. She takes the palm-sized spotted carcass into the hotel bathroom for a closer look. She cries as she touches it. “I saw hope,” she says.


As popular platforms like Facebook, X (formerly Twitter), and Instagram become major sources of research material, scientists must grapple with new challenges. Even experts can misidentify species in amateur photos when they can’t measure, touch, or see the creature for themselves. Researchers must meticulously review and confirm the records they’ve gathered to avoid false identifications. Some have been less thorough than others.

Last year, a group of European scientists published a paper claiming to have found the first record of a young goblin shark in the Mediterranean, a deep-sea species with a face straight out of a Ridley Scott sci-fi flick. They based their conclusion on a photo taken on a Mediterranean beach. But some experts noticed that the juvenile “shark” appeared to be missing a gill and was strangely rigid for a dead fish. McDavitt spotted the fraud immediately. The proof was on his living room shelf: a plastic goblin shark toy that matched the supposed animal in the picture. The authors retracted their paper after McDavitt and others raised concerns.

Scientists using social media data to study species that have been nearly eradicated by poaching run the risk of exposing those animals to further harm. “If it’s a very rare species, you don’t want to publicize the location where the species can be found because of potential misuse,” Jarić says. And the research raises a familiar ethical conundrum. In a social media–saturated world where personal privacy is itself endangered, how do you ethically scrape pictures and videos provided by the masses without their consent? For now, scientists manage this by anonymizing posts, blurring profile photos, and removing usernames.

Fish photo
The McDavitts of the world need months to compile data, searching for an animal rarely photographed. One day, artificial intelligence may make the job simpler. Photo by Melody Robbins.

And there is always the prospect of misinformation and falsehoods making it into data sets. Artificial intelligence (AI) may prove a complicated partner in this regard. Researchers like Sbragaglia have recruited coders to develop machine-learning models for disseminating massive arrays of data about a specific species. They hope these AI models will pull, in a matter of hours, databases of pictures and videos that the McDavitts of the world would need months to compile. But with the alarming advance of artificially generated images, AI could also hinder scientists’ ability to tell real pictures from fake ones. “This is terrifying,” Sbragaglia says. “But I think for the moment, it’s far away.”


On a windy day in June 2023, Kyne dives into the turquoise waters off the coast of Singkep Island, just south of the location where McDavitt discovered the first clown wedgefish post in 2019. Jungle-clad mountains loom in the distance. Palm trees lean drunkenly over white sand beaches. Simeon and other scientists watch from the boat as Kyne disappears into the depths, clutching an empty one-liter bottle. Fleets of commercial fishing boats dot the surrounding sea, underscoring the urgency of the task.

Kyne and Simeon are here to collect samples for an eDNA study, supported by three years of funding that the Save Our Seas Foundation supplied for the wedgefish search, thanks in large part to McDavitt’s findings. When a creature swims through the water, it sheds genetic material that can reveal its presence once water samples taken from that area are analyzed. When the survey results are back in six months to a year, the scientists hope they can zero in on where clown wedgefish are hiding. Ultimately, they hope to convince the Indonesian government to enact laws that specifically protect the species. They have some traction: officials have already sought Simeon’s advice on where to implement stricter protections for endangered marine animals.

As Kyne swims toward the ocean floor, the water grows thick with debris. He can barely see the bottle in his hand when he reaches the sandy bottom, unscrews the lid, and fills it with seawater that he hopes will contain the next clue in his team’s long quest. The clown wedgefish may remain a shrinking target in a murky sea, and Kyne has yet to see one alive. But now, as he caps the bottle and swims for the surface, he’s confident the species is still hanging on, somewhere beyond the silt and trash. McDavitt keeps finding evidence of the fish on Facebook, including several specimens from a new location on the Sumatran coast. All the team has to do is find them IRL—in real life.

This article first appeared in Hakai Magazine and is republished here with permission.

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‘Living material’ water filter uses bacteria to neutralize water pollutants https://www.popsci.com/technology/water-filter-cyanobacteria-3d-print/ Fri, 08 Sep 2023 18:15:00 +0000 https://www.popsci.com/?p=568893
3D printer making algae-based water decontaminate
The new creation safely dissolves after coming into contact with a specific molecule. UC San Diego

The algae-derived mixture can also safely break down after coming into contact with a molecular relative of caffeine.

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3D printer making algae-based water decontaminate
The new creation safely dissolves after coming into contact with a specific molecule. UC San Diego

Decontaminating water is as vital an endeavor as ever as pollution issues continue to flood the planet. Knowing this, researchers at the University of California San Diego just created the latest mind-bending tool to aid in future clean-up projects: a 3D-printed “engineered living material” made of seaweed polymers and genetically altered bacteria that breaks down organic pollutants in water.

As detailed via a new paper published in Nature Communications, the remarkable creation comes courtesy of a team working within the University of California San Diego’s Materials Research Science and Engineering Center (MRSEC). According to the project announcement, the team first hydrated a seaweed-derived polymer known as alginate. Meanwhile, the researchers genetically engineered a waterborne, photosynthetic bacteria called cyanobacteria to produce laccase, an enzyme capable of neutralizing organic pollutants like antibiotics, dyes, pharmaceutical drugs, and BPAs. The ingredients were then combined and passed through a 3D printer to produce a grid-like design whose surface area-to-volume ratio allowed the bacteria optimal access to light, gasses, and nutrients.

[Related: The US might finally regulate toxic ‘forever chemicals’ in drinking water.]

“This collaboration allowed us to apply our knowledge of the genetics and physiology of cyanobacteria to create a living material,” School of Biological Sciences faculty member Susan Golden said in a statement. “Now we can think creatively about engineering novel functions into cyanobacteria to make more useful products.”

To test their creation, the engineers introduced their decontaminator to water polluted by indigo carmine, a blue dye often used within denim textile manufacturing. The team’s grid-like, living tool managed to safely and effectively decolorize the water solution over the course of multiple days.

However, that still leaves the alginate-cyanobacteria mixture within the water. Replacing one foreign pollutant with foreign, synthesized bacteria doesn’t necessarily solve the larger problem of contamination. To solve this, the UC San Diego team further engineered their version of cyanobacteria to adversely respond to theophylline, a molecule similar to caffeine found in many teas and chocolates. Whenever the decontamination substance comes into contact with the molecule, the bacteria subsequently produces a specific protein to break down and destroy its own cells, thus getting rid of the substance.

“The living material can act on the pollutant of interest, then a small molecule can be added afterwards to kill the [cyanobacteria],” Jon Pokorski, a professor of nanoengineering and research co-lead, said in the announcement. “This way, we can alleviate any concerns about having genetically modified bacteria lingering in the environment.”

As useful as this living filer could already be in decontamination projects, the team hopes to eventually take their substance a step further by designing it to self-destruct without the need for additional outside chemicals.

“Our goal is to make materials that respond to stimuli that are already present in the environment,” Pokorski explained.

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This organ-failure detector is thinner than a human hair https://www.popsci.com/technology/kidney-transplant-sensor/ Fri, 08 Sep 2023 17:00:00 +0000 https://www.popsci.com/?p=568863
Kidney transplant sensor on researcher fingertip
The new sensor is thinner than a single human hair. Northwestern University

A new medical sensor can measure kidney temperature fluctuations as small as 0.004 degrees Celsius.

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Kidney transplant sensor on researcher fingertip
The new sensor is thinner than a single human hair. Northwestern University

Human bodies can reject organ transplants at any time—sometimes even years after the procedure itself. When this occurs, time is of the essence to potentially save not only the organ’s viability, but the life of a patient. Unfortunately, noticeable symptoms of organ rejection can show up late, but a tiny new medical device is showing immense promise in offering dramatically earlier detection times.

As detailed in a new study published September 8 in the journal Science researchers at Northwestern University have developed an ultra-thin, soft implant that adheres directly to a transplanted organ’s surface to monitor its health. In small animal clinical trials involving kidney transplants, rejection warning signs were identified as much as three weeks earlier than current methods.

[Related: The first successful pig heart transplant into a human was a century in the making.]

“I have noticed many of my patients feel constant anxiety—not knowing if their body is rejecting their transplanted organ or not. They may have waited years for a transplant… [t]hen, they spend the rest of their lives worrying about the health of that organ,” Lorenzo Gallon, a transplant nephrologist at Northwestern Medical who led the study’s clinical portion, said in a statement. “Our new device could offer some protection, and continuous monitoring could provide reassurance and peace of mind.”

According to John A. Rogers, a bioelectronics expert who led device development for the project, identifying rejection earlier can allow physicians to administer various therapies to prevent a patient from losing the organ, or even their lives.

“In worst-case scenarios, if rejection is ignored, it could be life threatening,” Rogers said via Friday’s statement. “The earlier you can catch rejection and engage therapies, the better. We developed this device with that in mind.”

At 0.3 cm wide, 0.7 cm long, and just 220 microns thick, the new sensor is thinner than a single human hair and smaller than your pinky fingernail. The device’s tininess is key to its ability to adhere, slipping beneath a kidney’s fibrous renal capsule layer to rest directly against the organ. Once positioned, the device’s extremely sensitive thermometer measures kidney temperature fluctuations as miniscule as 0.004 degrees Celsius. A miniature coin cell battery currently powers the device alongside Bluetooth capabilities to wireless stream data results to researchers.

Since tissue inflammation is often an early sign of complications, researchers were alerted much faster to potential problems than currently available detection methods like creatine and blood urea monitoring. Due to normal body fluctuations, those existing options are also far less reliable and sensitive than the new device.

“Bodies move, so there is a lot of motion to deal with. Even the kidney itself moves,” Rogers continued, explaining that the organ’s soft tissue isn’t ideal for suturing. “These were daunting engineering challenges, but this device is a gentle, seamless interface that avoids risking damage to the organ.”

Moving forward, the team intends to begin larger animal trials, along with potentially expanding to test on organs such as livers and lungs. They also hope to integrate new power sources capable of externally recharging the device’s battery, thus offering a more permanent monitoring solution.

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Scientists discover a cat-sized ancient koala in Australia https://www.popsci.com/environment/lumakoala-blackae-koala-australia/ Fri, 08 Sep 2023 15:00:00 +0000 https://www.popsci.com/?p=568844
An artist’s illustration of the 25 million year old Ditjimanka Lumakoala blackae, featuring (left to right) the wallaby-sized herbivore Muramura williamsi, an extinct koala relative named Madakoala devis,i and the calf-size lizard called Ilaria lawsone.
An artist’s illustration of the 25 million year old Ditjimanka Lumakoala blackae, featuring (left to right) the wallaby-sized herbivore Muramura williamsi, an extinct koala relative named Madakoala devis,i and the calf-size lizard called Ilaria lawsone. Peter Schouten

'Until now, there’s been no record of koalas ever being in the Northern Territory; now there are three different species from a single fossil site.'

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An artist’s illustration of the 25 million year old Ditjimanka Lumakoala blackae, featuring (left to right) the wallaby-sized herbivore Muramura williamsi, an extinct koala relative named Madakoala devis,i and the calf-size lizard called Ilaria lawsone.
An artist’s illustration of the 25 million year old Ditjimanka Lumakoala blackae, featuring (left to right) the wallaby-sized herbivore Muramura williamsi, an extinct koala relative named Madakoala devis,i and the calf-size lizard called Ilaria lawsone. Peter Schouten

Australia is currently home to the only living species of their endangered and iconic koalas, but there once were multiple species spread across the continent. Now, the discovery of another marsupial ancient relative is helping scientists fill in a 30 million year evolutionary gap. The findings are detailed in a study published September 4 in the journal Scientific Reports.

[Related: With bulging eyes and a killer smile, this sabertooth was an absolute nightmare.]

In 2014 and 2020, study co-author Arthur Crichton, a PhD student at Flinders University in Adelaide, Australia, found fossil teeth of the new species, named Lumakoala blackae, at the Pwerte Marnte Marnte fossil site in central Australia. The teeth are believed to be roughly 25 million years old. 

“Our computer analysis of its evolutionary relationships indicates that Lumakoala is a member of the koala family (Phascolarctidae) or a close relative, but it also resembles several much older fossil marsupials called Thylacotinga and Chulpasia from the 55 million-year-old Tingamarra site in northeastern Australia,” Crichton said in a statement

According to Chrichton, it was previously suggested that the enigmatic Thylacotinga and Chulpasia may have been more closely related to marsupials from South America.  This new discovery of Lumakoala suggests that they could actually be early relatives of herbivorous Australian marsupials including possums, kangaroos, koalas, and wombats.

“This group (Diprotodontia) is extremely diverse today, but nothing is known about the first half of their evolution due to a long gap in the fossil record,” said Crichton. 

If the study’s hypothesis is correct, the diprotodontian fossil record would be aged back by another 30 million years. Additionally, wombats, kangaroos, koalas and possums split off from other marsupials between roughly 65 million and 50 million years ago.

A chart comparing the upper molar morphology between Chulpasia jimthorselli, Lumakoala blackae and the modern koala.,
Comparison of upper molar morphology between Chulpasia jimthorselli, Lumakoala blackae, and the modern koala. CREDIT: A. Crichton (Flinders University)

“These Tingamarran marsupials are less mysterious than we thought, and now appear to be ancient relatives of younger, more familiar groups like koalas,” Robin Beck, study co-author and evolutionary biologist at the University of Salford in England, said in a statement. “It shows how finding new fossils like Lumakoala, even if only a few teeth, can revolutionize our understanding of the history of life on Earth.” 

The study also raises some new questions, including whether these relatives of herbivorous marsupials in Australia once lived in Antarctica and South America. According to Beck, some South American fossils look very similar to the marsupials found at the Tingamarra site. 

[Related: This 500-pound Australian marsupial had feet made for walkin.’]

It also reports that two other types of koala called Madakoala and Nimiokoala lived alongside Lumakoala and filled in different ecological niches in the forests that flourished in central Australia about 25 million years ago. The late Oligocene (about 23–25 million years ago) was  “kind of the koala heyday,” according to the Flinders University paleontologist and study co-author Gavin Prideaux.

“Until now, there’s been no record of koalas ever being in the Northern Territory; now there are three different species from a single fossil site,” Prideaux said in a statement. “While we have only one koala species today, we now know there were at least seven from the late Oligocene – along with giant koala-like marsupials called ilariids.”  

At this time, iliariids were the largest marsupials living in Australia, weighing in at up to 440 pounds. Iliariids lived alongside a strong-toothed wombat relative named Mukupirna fortidentata and a strange possum named Chunia pledgei.

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Leggy dinosaur species could be the latest feathery clue to bird evolution https://www.popsci.com/science/china-bird-dinosaur-discovery/ Wed, 06 Sep 2023 15:00:00 +0000 https://www.popsci.com/?p=568265
An artist’s illustration of Fujianvenator prodigiosus, an avialan theropod who lived during the Late Jurassic period and had a lower leg that was twice as long as its thigh.
An artist’s illustration of Fujianvenator prodigiosus, an avialan theropod who lived during the Late Jurassic period and had a lower leg that was twice as long as its thigh. ZHAO Chuang

The Fujianvenator prodigiosus was a pheasant-sized swamp creature that lived around 150 million years ago.

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An artist’s illustration of Fujianvenator prodigiosus, an avialan theropod who lived during the Late Jurassic period and had a lower leg that was twice as long as its thigh.
An artist’s illustration of Fujianvenator prodigiosus, an avialan theropod who lived during the Late Jurassic period and had a lower leg that was twice as long as its thigh. ZHAO Chuang

A newly discovered early bird-like dinosaur species is filling in some of the holes in the dinosaur-to-bird evolutionary story. The new species, named Fujianvenator prodigiosus, has a strange mixture of physical features shared with other extinct prehistoric animals from therapod dinosaurs to birdlike troodontids. This unique beast was described in a study published September 6 in the journal Nature. 

[Related: Birds are dinosaurs, and this fossil detective has rooms full of bones to prove it.]

Birds diverged from theropod dinosaurs by the Late Jurassic (about 161 million to 146 million years ago), but the general understanding of the earliest evolution of the clade comprising most modern birds, known as Avialae, has been slowed due to a limited diversity of fossils from the Jurassic. No known avialans have been reported from the Yanliao Biota paleontological site in northeast China, which dates back to the Middle–Late Jurassic about 166–159 million years ago or in the the slightly younger German Solnhofen Limestones, which preserves an early genus of avian dinosaurs called Archaeopteryx. This leaves a gap of about 30 million years before the oldest known record of Cretaceous birds. 

Jurassic era avialans are a critical key to deciphering the evolutionary origin of the avialan body,  and this elusive group is key to piecing together the origin of birds. That’s where the fossilized remains of the 148 to 150-million-year-old avialan theropod Fujianvenator prodigiosus comes in. It has some physical traits shared with extinct avialans, the small and bird-like troodontids that lived during the Cretaceous Period, and theropod dinosaurs called dromaeosaurids that were similar to raptors and also lived during the Cretaceous. According to the team on this study, this mixture shows the impact of evolutionary mosaicism–different rates of evolutionary change in body structures and function– in early bird evolution.

An artist's illustration of the 150-million-year-old avialan theropod Fujianvenator prodigiosus. CREDIT: ZHAO Chuang
An artist’s illustration of the 150-million-year-old avialan theropod Fujianvenator prodigiosus. CREDIT: ZHAO Chuang.

A joint research team from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences in Beijing and the Fujian Institute of Geological Survey (FIGS) described and the avialan theropod that was found in Zhenghe County, Fujian Province in southeastern China.

“Our comparative analyses show that marked changes in body plan occurred along the early avialan line, which is largely driven by the forelimb, eventually giving rise to the typical bird limb proportion,” study co-author and paleontologist Min Wang from IVPP said in a statement. “However, Fujianvenator is an odd species that diverged from this main trajectory and evolved bizarre hindlimb architecture.”

[Related: Birds are so specialized to their homes, it shows in their bones.]

During the Late Jurassic-Early Cretaceious, southeastern China saw some intense tectonic activities that resulted in a lot of movement of magma below the Earth’s surface. This created some deep basins with the Earth including where Fujianvenator was found.

Fujianvenator prodigiosus was likely about the size of a present day pheasant and had a tibia (lower leg) that is twice as long as its femur (thigh), which is a previously unknown condition for non-avian dinosaurs. This suggests that the bird was either a high-speed runner or a long-legged wader and it likely lived in swamps. This new finding contrasts with other early avialans, which are believed to have been more tree and sky-dwelling.  

Fujianvenator’s remains were found among a diverse collection of vertebrate fossils dominated by aquatic and semiaquatic species, including turtles and ray-finned fish. The authors named this fossil collection the Zhenghe Fauna. This diverse array of inhabitants and environment suggests that it was the site of emerging Jurassic vertebrate fauna around the time when Fujianvenator was there. This find and timing fills in an important gap in our understanding of ecosystems in Late Jurassic Northeast Asia and the team plans to continue to explore Zhenghe and other nearby areas.

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Our tree-climbing ancestors evolved our abilities to throw far and reach high https://www.popsci.com/science/shoulder-evolution-primates/ Wed, 06 Sep 2023 12:00:00 +0000 https://www.popsci.com/?p=568244
Two monkeys sitting in a forest. Dartmouth researchers report that apes and early humans evolved more flexible shoulders and elbows than monkeys to safely get out of trees. For early humans, these versatile appendages would have been essential for gathering food and deploying tools for hunting and defense.
Dartmouth researchers report that apes and early humans evolved more flexible shoulders and elbows than monkeys to safely get out of trees. For early humans, these versatile appendages would have been essential for gathering food and deploying tools for hunting and defense. Luke Fannin, Dartmouth

Football season really started 20 million years ago with this evolutionary quirk.

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Two monkeys sitting in a forest. Dartmouth researchers report that apes and early humans evolved more flexible shoulders and elbows than monkeys to safely get out of trees. For early humans, these versatile appendages would have been essential for gathering food and deploying tools for hunting and defense.
Dartmouth researchers report that apes and early humans evolved more flexible shoulders and elbows than monkeys to safely get out of trees. For early humans, these versatile appendages would have been essential for gathering food and deploying tools for hunting and defense. Luke Fannin, Dartmouth

The mechanics of how athletes like New York Giants quarterback Daniel Jones’ are able to throw a perfect spiral or how wide receiver Darius Slayton may extend his elbow to reach for the catch may have ancient roots. These skills may have first evolved as a natural braking system for our primate ancestors who simply needed a safe way to get out of trees

[Related: Chilly climates may have forged stronger social bonds in some primates.]

In a study published September 6 in the journal Royal Society Open Science, a team from Dartmouth found that apes and early human ancestors likely evolved free-moving shoulders and flexible elbows as a way to slow their descent from trees while gravity pulled down on their bodies. Versatile appendages that could throw spears for hunting and defense, climb trees, and gather food were essential for survival—especially as early humans left forests for grassy savannas.

“There’s a lot we still don’t understand about the origin of apes,” study co-author and Dartmouth University paleoanthropologist Jeremy DeSilva tells PopSci. “There was a common ancestor to monkeys and apes that lived about 25 to 30 million years ago and then there was a divergence and now we have these two different kinds of primates. But why the convergence?”

One of the possibilities is different ecological, physical, and behavioral niches related to primate size. The first apes evolved about 20 million years ago and are bigger than other early primates. Getting out of a tree presented a new set of challenges for these bigger primates, since typically the bigger the animal, the greater the risk of injury from a fall. Natural selection would have eventually favored anatomies that allowed early apes to safely descend from the trees. 

In the study, the team used sports-analysis and statistical software to compare videos and still-frames of chimpanzees and small monkeys called mangabeys climbing in the wild. They saw that mangabeys and chimps climbed up the trees similarly, with their shoulders and elbows mostly bent close to the body. 

However, when it was time to climb down, chimpanzees extended their arms above their heads to hold onto branches, similar to how a person going down a ladder, as their weight pulls them down. This process called “downcliming” appears to be significant in the evolution of apes and early humans.

“Our study broaches the idea of downclimbing as an undervalued, yet incredibly important factor in the diverging anatomical differences between monkeys and apes that would eventually manifest in humans,” study co-author and Dartmouth graduate student Luke Fannin said in a statement

[Related: How to hike downhill safely and comfortably.]

These flexible shoulders and elbows passed on from ancestral apes would have allowed early humans such as Australopithecus to climb into trees at night for safety and then come down in the daylight unscathed. Once Homo erectus could use fire to protect itself at night, the human form took on the broader shoulders capable of a 90-degree twist that worked with free moving shoulders and elbows to make human ancestors excellent shots with a spear for hunting.

“The idea that downclimbing could be such a strong evolutionary force as to change the nature of how our bones and range of motion evolved was very fascinating,” study co-author Mary Joy tells PopSci. “Not a lot of the field really thinks about downclimbing as its own motion with implications on natural selection.” Joy brought her experience as a trail runner and athlete to the study to bring in a different perspective to looking at biological sciences and evolution. 

The team also used skeletal collections from Harvard University to study the anatomical structure of chimpanzee arm alongside remains in The Ohio State University’s collections to study  mangabey arms. Chimpanzees are more like humans than mangabeys and have a shallow ball-and-socket shoulder that allows for a greater range of movement. Chimps can also fully extend their arms due to a reduced length of bone located just behind the elbow called the olecranon process.

Three mangabeys in a tree. The researchers used sports-analysis software to compare the climbing movements of chimpanzees and mangabeys (pictured). They found that chimps support their greater weight when climbing down by fully extending their arms above their heads thanks to shallow, rounded shoulder joints and shortened elbow bones that are similar to those in humans. Mangabeys, which are built more like cats or dogs, have less flexibility and position their shoulders and elbows roughly the same when climbing up or down. CREDIT: Luke Fannin, Dartmouth
The researchers used sports-analysis software to compare the climbing movements of chimpanzees and mangabeys (pictured). They found that chimps support their greater weight when climbing down by fully extending their arms above their heads thanks to shallow, rounded shoulder joints and shortened elbow bones that are similar to those in humans. Mangabeys, which are built more like cats or dogs, have less flexibility and position their shoulders and elbows roughly the same when climbing up or down. CREDIT: Luke Fannin, Dartmouth.

Mangabeys and other monkeys are built more like four-legged animals like cats and dogs, with deep pear-shaped shoulder sockets and elbows that have a protruding olecranon process, which makes the joint look like the letter L. These joints are more stable, but they have a more limited range of movement and flexibility.

The analysis showed that the angle of a chimp’s shoulders was 14 degrees greater during their descent than when scaling a tree. The arm also extended outward at the elbow 34 degrees more when climbing down a tree than climbing up. The angles at which the mangabeys positioned their shoulders and elbows were only about four degrees or less when ascending a tree versus downclimbing.

“If cats could talk, they would tell you that climbing down is trickier than climbing up and many human rock climbers would agree. But the question is why is it so hard,” study co-author and 

anthropologist and evolutionary biologist Nathaniel Dominy said in a statement. “The reason is that you’re not only resisting the pull of gravity, but you also have to decelerate. 

[Related: Lucy, our ancient human ancestor, was super buff.]

According to DeSilva, the question of “how did we not see this before” in regards to downclimbing was one of the most surprising parts of the study. The fresh eyes of both Joy and graduate student Fannin were crucial in uncovering one of evolution’s hidden wonders. 

“Our evolutionary ancestry is this wonderful example of how evolution just sort of tinkers and tweaks pre-existing forms,” says DeSilva. “Our bodies are bodies that have been just tweaked and modified through natural selection over millions of years, to give us the bodies we have now, but there are all these wonderful echoes of our ancestry in our bodies today.”

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Paper cups still use plastic—and it’s a problem for the planet https://www.popsci.com/environment/paper-cups-environment-plastic/ Tue, 05 Sep 2023 18:00:00 +0000 https://www.popsci.com/?p=568035
Fiver different types of paper cups sitting are sitting on a table. Some have eco-friendly labeling and one warns of plastic chemical leaching. Paper cups are replacing plastic cups on the market, but paper cups can also be toxic to living organisms, shows a new study from the University of Gothenburg.
Paper cups are replacing plastic cups on the market, but paper cups can also be toxic to living organisms, shows a new study from the University of Gothenburg. Olof Lönnehed

A layer of plastic on paper cups used to keep hot drinks away from skin could be leaching toxic chemicals.

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Fiver different types of paper cups sitting are sitting on a table. Some have eco-friendly labeling and one warns of plastic chemical leaching. Paper cups are replacing plastic cups on the market, but paper cups can also be toxic to living organisms, shows a new study from the University of Gothenburg.
Paper cups are replacing plastic cups on the market, but paper cups can also be toxic to living organisms, shows a new study from the University of Gothenburg. Olof Lönnehed

Much like the paper straws that were ushered in to reduce the use of single use plastic straws, paper cups may also be problematic for the environment. A study published in the August issue of the journal Environmental Pollution found that many paper cups are coated with a thin coating of plastic. This layer keeps liquids from seeping into the paper, but can emit toxic substances.

[Related: ‘Forever chemicals’ detected in paper and plastic straws.]

In the study, a team of researchers from the University of Gothenburg in Sweden tested the effect of disposable cups made from different materials on the larvae of the butterfly mosquito. The paper and plastic cups were placed in temperate water or sediment and were left to leach for up to four weeks. Then, the larvae were housed in aquariums that had the water or sediment that had been tainted by paper and plastic cups. 

The larvae grew less in the sediment regardless of the source of contamination.The exposure to the tainted water from both cup types appeared to hinder their development. 

“All of the mugs negatively affected the growth of mosquito larvae,” study co-author and ecotoxicologist and fish biologist Bethanie Carney Almroth said in a statement

Since paper isn’t resistant to either water or fats, the paper used to package foods and liquids needs to be treated with a top coat that protects the paper and user from what is inside. The plastic film is often made of a type of bioplastic called polylactide (PLA). Bioplastics are produced from renewable resources instead of much more frequently used fossil fuels. PLA is commonly produced from corn, cassava, or sugarcane and while it is often believed to be biodegradable, this study shows that it can still be toxic.

“Bioplastics do not break down effectively when they end up in the environment, in water. There may be a risk that the plastic remains in nature and resulting microplastics can be ingested by animals and humans, just as other plastics do. Bioplastics contain at least as many chemicals as conventional plastic,” says Carney Almroth.

Some of the chemicals in plastics are known to be toxic, while others are still unknown. According to the team, paper presents a potential health hazard compared to other materials and it is becoming more common as society shifts away from plastics and people become exposed to the chemicals in the plastic through contact with food. The team did not perform a chemical analysis to see which substances had leached from the paper cups and into the water and damaged the larvae, but they suspect it was a mixture of various chemicals. 

[Related: Plastic garbage in the sea is a life raft for pathogens.]

The carbon footprint of reusable plastic cups is tough to pin down, and scientists don’t know if they are better in terms of chemical leaching compared to their trashable counterparts. Some estimates find that a reusable cup must be used between 20 and 100 times to offset its greenhouse gas emissions when compared to a disposable cup, due to the high amount of energy needed to make these popular options durable and the hot water required to keep it clean. However, these reusable options do last longer and have better potential to offset the impacts of disposable cups. 

“When disposable products arrived on the market after the Second World War, large campaigns were conducted to teach people to throw the products away, it was unnatural to us! Now we need to shift back and move away from disposable lifestyles. It is better if you bring your own mug when buying take away coffee. Or by all means, take a few minutes, sit down and drink your coffee from a porcelain mug,” said Carney Almroth.

Currently, the United Nations is working to negotiate a binding agreement to end the spread of plastics.  Carney Almroth is a member of a council of scientists called the Scientists Coalition for an Effective Plastics Treaty (SCEPT) which contributes up-to-date scientific evidence to these negotiations. SCEPT is calling for a rapid phasing out of unnecessary and problematic plastics, as well as added vigilance to avoid the repeat mistakes of replacing one bad product with another.

“We at SCEPT are calling for transparency requirements within the plastics industry that forces a clear reporting of what chemicals all products contain, much like in the pharmaceutical industry,” said Carney Almroth. “But the main goal of our work is to minimize plastic production.”

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Couples often share more common traits than we might think https://www.popsci.com/science/dating-similar-traits/ Tue, 05 Sep 2023 14:05:00 +0000 https://www.popsci.com/?p=567898
A couple standing on the beach in warm sunlight.
Traits such as and religious attitudes, level of education, and certain measures of IQ showed particularly high correlations in a new study. Deposit Photos

Most opposite sex romantic partners share traits ranging from drinking habits to political leanings.

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A couple standing on the beach in warm sunlight.
Traits such as and religious attitudes, level of education, and certain measures of IQ showed particularly high correlations in a new study. Deposit Photos

Finding lasting love can be really difficult. We’ve all heard the annoying adages like “there’s plenty of fish in the sea,” not to mention the old “opposites attract” chestnut. However, many people tend to end up being quite similar to their partners, according to the results of a study published August 31 in the journal Nature Human Behaviour.

[Related: Social relationships are important to the health of aging adults.]

The new research included numerous studies dating back more than a century. The team examined 130 traits from millions of couples, ranging from political leanings to age of first sexual intercourse to substance use habits. For between 82 and 89 percent of traits analyzed, partners were more likely than not to be similar. In only one part of the analysis, and for only three percent of studied traits, did individuals tend to be coupled with someone who is demonstrates an opposing trait.

In addition to shedding light on some of those unseen forces that may shape human relationships, this research could have some important implications for the field of genetic research.

“A lot of models in genetics assume that human mating is random. This study shows this assumption is probably wrong,” study co-author and University of Colorado at Boulder psychologist and neuroscientists Matt Keller, said in a statement. Keller noted that a tendency called assortative mating—when individuals with similar traits couple up—can actually skew findings of genetic studies.

To find their results, the team conducted both a meta-analysis of previous research and their own original data analysis. In the meta-analysis, they examined 22 traits across 199 studies of millions of male-female co-parents, engaged pairs, married pairs, or cohabitating pairs. The oldest study in this analysis was conducted back in 1903. They also used a dataset called the UK Biobank to analyze 133 traits across almost 80,000 opposite-sex pairs in the United Kingdom.

Same sex couples were not included in the research because the patterns in these types of partnerships may differ significantly. The authors are now pursuing those relationships in a separate study.

[Related: These fuzzy burrowers don’t need oxytocin to fall in love.]

Traits such as political and religious attitudes, level of education, and certain measures of IQ showed particularly high correlations. For example, on a scale of 0 meaning no correlation and 1 meaning couples always share a trait, the correlation for political values was .58. Traits surrounding substance use also showed high correlations, with heavy drinkers, smokers, and teetotalers tending to strongly pair with those who share similar traits. Traits like height and weight, medical conditions, and personality showed much lower but still positive correlations. For example, the correlation for neuroticism was .11.

Interestingly, some traits, such as extroversion, did not have much of a correlation.

“People have all these theories that extroverts like introverts or extroverts like other extroverts, but the fact of the matter is that it’s about like flipping a coin: Extroverts are similarly likely to end up with extroverts as with introverts,” study co-author and University of Colorado at Boulder PhD student Tanya Horwitz said in a statement

The meta-analysis found “no compelling evidence” that on any trait that opposites attract. However, in the sample from the UK Biobank, the team did find a handful of traits in which there seemed to be a small negative correlation, including hearing difficulty, tendency to worry, and whether someone is more of a morning person or night person (called chronotype). Additional studies will be needed to understand those findings, according to the team. 

Some of the less-frequently studied traits including number of sexual partners and whether an individual had been breastfed as a child also showed some correlation.

“These findings suggest that even in situations where we feel like we have a choice about our relationships, there may be mechanisms happening behind the scenes of which we aren’t fully aware,” said Horwitz.

According to the authors, couples could share traits for a variety of reasons, including growing up in a similar area. Some people are simply attracted to those who are similar based on the traits studied, and some couples grow more similar the longer they stay in the relationship. 

These pairings could lead to some downstream genetic consequences. For example, if short people are more likely to produce offspring with a similar height and vice versa, there could be more people at the height extremes in the next generation. This same thing apply for medical, psychiatric, and other traits according to Horowitz. 

Some of the social implications include those with similar educational backgrounds continuing to pair up, which could widen socioeconomic divides.

The team cautions that the correlations found were fairly modest and should not be overstated or misused to promote an agenda. Assortative mating has historically been dangerously co-opted by the eugenics movement, which gained traction during the early 20th century.

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The next frontier in saving the world’s heaviest parrots: genome sequencing https://www.popsci.com/environment/genomic-sequencing-kakapo/ Fri, 01 Sep 2023 12:00:00 +0000 https://www.popsci.com/?p=567328
A kākāpō sitting in its burrow. They can live up to 90 years and forage on the ground for food since they are flightless birds.
A kākāpō sitting in its burrow. They can live up to 90 years and forage on the ground for food since they are flightless birds. Jake Osborne

Kākāpō's were once considered 'doomed to early extermination.' Now these quirky New Zealand birds are slowly making a comeback.

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A kākāpō sitting in its burrow. They can live up to 90 years and forage on the ground for food since they are flightless birds.
A kākāpō sitting in its burrow. They can live up to 90 years and forage on the ground for food since they are flightless birds. Jake Osborne

New Zealand’s quirky and critically endangered kākāpō have begun to return to the country’s mainland for the first time in almost 40 years. Kākāpōs are the heaviest parrots in the world, with some exceeding six pounds, and they have a lifespan of up to 90 years. Like penguins and ostriches, they can’t fly, so kākāpōs climb trees and forage on the ground for nuts and seeds to eat.  

[Related: A flightless parrot is returning to mainland New Zealand after a 40-year absence.]

The big, green, nocturnal birds used to be widespread across New Zealand, but were hunted to near extinction and threatened by non native predators like cats and dogs. Popular Science magazine described these “curious” green birds as already being “doomed to early extermination” all the way back in April 1895

The roughly 250 or so individual birds that are left are managed by New Zealand’s Department of Conservation (DOC) and the South Island’s Ngāi Tahu tribe on five islands that are free of predators. Now equipped with 21st Century genetic science, research platform Genomics Aotearoa is funding high-quality genetic sequencing of almost the entire kākāpō population. The results of an early study of how these full genomic sequences will help manage the health of these iconic birds was published August 28 in the journal Nature Ecology & Evolution.

Establishing genetic sequencing methods is not expected to only play a part in kākāpō survival, but other endangered species throughout New Zealand and the rest of the world. Conservation genomics is part of a growing trend in the field. In 2019, a team from San Diego and the University of Hawaii used advanced DNA sequencing technology to create a nearly complete genome assembly for Hawaii’s only remaining lineage of the crow family ‘alalā (Corvus hawaiiensis). The sequencing gave conservationists critical clues into the disease susceptibility, population-level diversity, and genetic load of the alalā to better inform their policies.

A close up of a female bird named Solstice. Solstice is one of New Zealand’s largest female kākāpōs, often weighing 4.5 pounds, even without the help of supplementary feeding. CREDIT: DOC.
Solstice is one of New Zealand’s largest female kākāpōs, often weighing 4.5 pounds, even without the help of supplementary feeding. CREDIT: DOC.

The same information could help the kākāpō thrive. This work over the last year has produced two very significant outcomes. First, it has given the team an in-depth understanding of kākāpō biology. It has also produced a high-quality code and reusable pipeline, which allows other researchers to rapidly use these methods in their own work and advanced New Zealand’s genomic capability.

“Kākāpō suffer from disease and low reproductive output, so by understanding the genetic reasons for these problems, we can now help mitigate them,” Andrew Digby, the DOC’s Science Advisor for Kākāpō Recovery, said in a statement. “It gives us the ability to predict things like kākāpō chick growth and susceptibility to disease, which changes our on-the-ground management practices and will help improve survival rates.”

[Related: Eavesdropping on pink river dolphins could help save them.]

Diby added that the Kakapo125+ project is another example of how genetic data can assist population growth. The 125 refers to the number of kākāpō living when the project began in 2015. “The novel genetic and machine learning tools developed can be applied to improve the productivity and survival of other taonga under conservation management,” said Digby.

The sequencing technique was developed by University of Otago microbial scientist Joseph Guhlin and an international team of researchers and could have impacts outside of New Zealand. 

“Using technology created by Google, we have achieved what is likely the highest quality variant dataset for any endangered species in the world,” said Guhlin. “This dataset is made available, through DOC and Ngai Tahu, for future researchers working with kākāpō.”

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Maine’s puffins show another year of remarkable resiliency https://www.popsci.com/environment/puffin-maine-rebound/ Thu, 31 Aug 2023 15:00:00 +0000 https://www.popsci.com/?p=567239
Two Atlantic puffins stand on a white rock above the ocean, with another group of puffins in the background, Atlantic puffins are sometimes nicknamed “sea parrots,” and their chicks hatch in Maine in early July.
Atlantic puffins are sometimes nicknamed “sea parrots,” and their chicks hatch in Maine in early July. Deposit Photos

Despite enormous challenges from climate change, the fledgling seabirds had their second consecutive rebound year.

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Two Atlantic puffins stand on a white rock above the ocean, with another group of puffins in the background, Atlantic puffins are sometimes nicknamed “sea parrots,” and their chicks hatch in Maine in early July.
Atlantic puffins are sometimes nicknamed “sea parrots,” and their chicks hatch in Maine in early July. Deposit Photos

For the second year in a row, the Atlantic puffins living on the rocky islands off Maine’s coast had a rebound year for fledgling chicks, all in the face of record warm waters due to climate change. This second consecutive rebound year is welcome news, after 90 percent of nesting puffins failed to raise a single chick in 2021 while the climate change in New England has put this species, and others like humpback whales and the zooplankton at the base of the Gulfs food web, in jeopardy.

[Related: Cyclones can be fatal for seabirds, but not in the way you think.]

The Gulf of Maine and its bays are among the world’s fastest-warming bodies of water. Since the early 1980s, it has warmed about four degrees Fahrenheit, while the global ocean has risen by about 1.5 degrees Fahrenheit in the same period of time. The rising heat has affected the fish stocks in the area that puffins and other species rely on. Haddock used to make up a large portion of puffin diets, but populations have fluctuated in recent years, first increasing in 2017 due to federal management to this year showing signs of a decrease

However, a small eel-like fish called the sand lance has been abundant this year. The fish are only about four to eight inches long, but are high in fats and make them a great forage fish for seabirds. A 2020 study found that 72 Atlantic Ocean animal species from whales to bluefish to gannets eat sand lances in the waters from Greenland to North Carolina. 

According to the Maine Monitor, the sand lance were less abundant in the region by mid-July, but the puffins were found feasting on a mixture of haddock, hake, and redfish depending upon where they were. Don Lyons, the director of conservation science at National Audubon Society’s Seabird Institute, told the Maine Monitor, “I can’t offhand recall such a seamless transition from one fish to another. It tells you a lot about the resourcefulness of puffins and at the same time, it’s a reminder of how much we still don’t know of when and where food is for seabirds, and how fast that all can change.”

Lyons estimated that there are now as many as 3,000 puffins in Maine, what he calls a stable population. In 2022, about two-thirds of the puffins fledged—or developed wing feathers that are large enough for flight. While they didn’t reach that number this year, they had a better season than the catastrophic 2021 season despite a rainy and hot summer. The Audubon Society’s Project Puffin has been monitoring the population for 50 years and uses decoys, mirrors, and recordings to attract the birds to suitable nesting sites to raise the next generation of birds.

This cozy burrow 21 miles off the coast of Maine is where Atlantic puffins breed and raise their young. CREDIT: Audubon/Explore.org

Maine’s puffin population was once as low as 70 pairs on Matinicus Rock 25 miles off the coast. They were hunted for their feathers and meat in the early 20th Century, but by the 1970’s Audubon conservationists worked to grow puffin colonies in the state, by bringing chicks from Canada to Maine’s Eastern Egg Rock. Puffins still call that tiny rock home, in addition to Seal Island and Petit Manan Island. Live cams keep an eye on them and volunteers and scientists monitor their progress every year.

Currently, Maine’s population are the only breeding Atlantic puffins in the United States. The species lives in areas of the North Atlantic from Maine and Canada eastward to Europe. Iceland, a country well known for its puffins, has seen the puffin populations decline by 70 percent in 30 years largely due to lack of food due to warming oceans.

[Related: Emperor penguins suffer ‘unprecedented’ breeding failure as sea ice disappears.]

While this ability to reproduce despite huge environmental changes does speak to their resiliency as a species, puffins are still at risk of long term dangers from marine heat waves, sea level rise threatening nesting sites, and a loss of food.  

“The problem with climate change is these breeding failures and low breeding productivity years are now becoming chronic,” Bill Sydeman, president and chief scientist of the California-based Farallon Institute, told the AP. “There will be fewer young birds in the population that are able to recruit into the breeding population.”

Some of the ways to help Maine puffin population and other coastal birds in the face of this constant uncertainty include Audubon’s adopt-a-puffin program and advocating for your local seabirds by contacting regional elected officials.

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Florida’s aquatic animals prepare early for storms like Hurricane Idalia https://www.popsci.com/science/can-animals-feel-hurricanes/ Wed, 28 Sep 2022 21:00:00 +0000 https://www.popsci.com/?p=473702
A manatee swims through blue water, surrounded by a school of fish
Even though manatees know what to do in a hurricane, their curiosity can get them in trouble. Keith Ramos, USFWS

Sharks, manatees, and gators don’t need an evacuation order to know when a storm might be trouble.

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A manatee swims through blue water, surrounded by a school of fish
Even though manatees know what to do in a hurricane, their curiosity can get them in trouble. Keith Ramos, USFWS

Weeks before we even think about getting sandbags or boarding up windows to prevent hurricane damage, an underwater evacuation begins. Sharks, sea snakes, and other wildlife will make preparations to escape becoming trapped or hurt as massive storms approach a coast. 

Much of Florida’s aquatic life—including species as diverse as manatees and alligators—know what to do in a storm like Hurricane Idalia. After all, these native animals have had millions more years of practice than us. But those age-old skills will only become more useful as hurricanes become more intense from climate change. 

“Aquatic animals respond to storms for the same reason we do—to avoid injury, death, and the destruction from hurricanes,” says Bradley Strickland, a postdoctoral researcher who studies aquatic animal response to hurricanes and climate change at William and Mary’s Virginia Institute of Marine Science. Still, some animals are better equipped to weather or evade the storms than others. And sharks are among the best. 

[Related: Sharks are learning to love coastal cities]

Even when a hurricane is far on the horizon, the atmosphere changes: the barometric pressure drops. “From two weeks out of a hurricane, sharks can actually detect the change and start heading for deeper water,” says Neil Hammerschlag, director of the shark research and conservation program at the University of Miami. The air around a hurricane decreases in pressure as a storm strengthens and wind speeds increase. Sharks can sense that, allowing them to flee long before Florida’s human residents were given mandatory evacuation orders. 

“Similar to the way we use meteorological technologies and observations about the changing wind and temperature before a storm, aquatic animals have ways to sense the approach of a storm,” Strickland says. Sharks use their sensitive inner ears to detect a gathering storm’s pressure changes, he adds. And, because of their incredible swimming abilities (some can swim up to 45 miles per hour), they can quickly escape oncoming storms—that is, if they choose to. 

Smaller shark species and juveniles opt to escape to deeper water to avoid the turbulence near the shore. For them, “staying in shallow water would be like a shark tornado,” Hammerschlag says, because hurricanes can push currents up to 300 feet below the ocean’s surface. For smaller sharks that remain in the shallows, they risk being swept inland.

Yet other larger predators, like tiger sharks that grow up to 14 feet and 1,400 pounds, view hurricanes as an opportunity for the ultimate sea smorgasbord. By tracking tiger sharks during and after Hurricane Irma, Hammerschlag noticed that “not only did they not run away, but they may have been taking advantage of the things that were dying, either birds that got washed into the water or fish and invertebrates that collided with debris.” After the storm, he adds, there were “higher numbers of tiger sharks in the area for about two weeks.”

For aquatic and semi-aquatic animals that can’t ride out the storm or swim beyond its reach, finding shelter may be the superior option for survival. “Sea snakes will seek refuge in volcanic rocks to avoid typhoons,” Strickland says. “Alligators likely hunker down to weather a storm by finding easy to get in and out of places,” he adds. Some smaller gators may get swept away by hurricanes; others might change their foraging patterns altogether to stay safe. 

Other species may be less lucky. After Hurricane Ian struck Florida in 2022, clean-up crews had to remove debris from the holes where burrowing owls live, since the threatened birds can’t claw through the trash on their own, as one wildlife rehabilitation expert told CNN. And when storms shove salty seawater inland, increases in salinity can disturb trees or turtles that dwell in freshwater ecosystems.

Along the coast, graceful manatees, too, have been found in particularly sticky situations post-hurricane. Although weight-wise they are comparable to a tiger shark, speed-wise they are definitely not, cruising up to 15 mph only if they really push it. And try as they might to hunker down before a storm, this doesn’t always work out for them. Instead, they may get swept out of coastal waters by floods. Others, curious to explore new streams, have been found stuck in smaller ponds, forests, or even by roads after post-storm swims through flooded areas. Yet hurricanes rank low on the dangers to manatees, a threatened keystone species in Florida often imperiled by watercraft.

Even if Hurricane Idalia is the first big tempest that a Floridian animal will experience, the odds are good it will take some kind of action. “We see animals evacuating the places they call home in advance of a major storm despite, in some cases, having never experienced a hurricane within their lifetime,” Strickland says. “This shows just how innate it is to protect yourself from a storm by preparing or fleeing compared to just waiting it out.”

This post has been updated. It was originally published on September 28, 2022.

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A three-eyed organism roamed the seas half a billion years ago https://www.popsci.com/environment/three-eyed-cambrian-arthropod/ Wed, 30 Aug 2023 13:00:00 +0000 https://www.popsci.com/?p=566874
An artistic reconstruction of Kylinxia, a relative of present day insects and crustaceans. It has two extended forelimbs, a round and segmented body, and three eyes on its head.
An artistic reconstruction of Kylinxia, a relative of present day insects and crustaceans. X. Wang

The shrimpy creature is filling in some evolutionary gaps.

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An artistic reconstruction of Kylinxia, a relative of present day insects and crustaceans. It has two extended forelimbs, a round and segmented body, and three eyes on its head.
An artistic reconstruction of Kylinxia, a relative of present day insects and crustaceans. X. Wang

A newly discovered three-eyed relative is disappointingly unrelated to the eerie three-eyed ravens of Game of Thrones. But this Cambrian-era beast is a relative of today’s insects and boasts some fearsome limbs. The unique fossilized animal was described in a study published August 28 in the journal Current Biology

[Related: This ancient ‘mothership’ used probing ‘fingers’ to scrape the ocean floor for prey.]

The animal, scientific name Kylinxia, was found in 520 million year old rocks in a fossil deposit called the Cambrian Chengjiang biota near the town of Chengjiang in southern China. More than 250 species of exceptionally well-preserved fossil organisms have already been described from this location, which gives scientists a glimpse of what was going on in the world’s oceans as they developed. 

Importantly, Kylinxia is filling in some evolutionary gaps in our understanding of the evolution of animals known as arthropods. This phylum of animals includes insects, crabs, shrimp, scorpions, spiders, and centipedes among others. Arthropods have an exoskeleton made of a tough material called chitin that is mineralized with calcium carbonate, as well as a body divided into segments and paired jointed appendages. They are considered some of Earth’s most successful species and over 85 percent of all known animal species are classified as arthropods.

Kylinxia was about the size of a large shrimp, had a pair of limbs that it likely used to catch prey, and a signature trio of eyes on its head. 

“Most of our theories on how the head of arthropods evolved were based on these early-branching species having fewer segments than living species,” Greg Edgecombe, a co-author of the study and arthropod evolution expert at London’s Natural History Museum, said in a statement. “Discovering two previously undetected pairs of legs in Kylinxia suggests that living arthropods inherited a six-segmented head from an ancestor at least 518 million years ago.”

After its initial discovery, Kylinxia was imaged using a CT scanner. The scan revealed that more soft parts of the animals’ anatomy were also buried in the rock. While there are plenty of species of arthropods preserved in the fossil record, most fossils only preserve the hard skeletons. 

[Related: Newly discovered fossils give a whole new meaning to jumbo shrimp.]

“The preservation of the fossil animal is amazing,” study co-author and University of Leicester PhD student Robert O’Flynn said in a statement. “After CT-scanning we can digitally turn it around and literally stare into the face of something that was alive over 500 million years ago. As we spun the animal around, we could see that its head possesses six segments, just as in many living arthropods.”

CT images of the fossil animal Kylinxia zhangi from southern China, courtesy of Professor Yu Liu, Yunnan University. The animal is the size of a large shrimp, with its front end to the right. The top image clearly shows the segmentation of the body and the large eyes at the front. The bottom image shows the large frontal limbs extended.
CT images of the fossil animal Kylinxia zhangi from southern China, courtesy of Professor Yu Liu, Yunnan University. The animal is the size of a large shrimp, with its front end to the right. The top image clearly shows the segmentation of the body and the large eyes at the front. The bottom image shows the large frontal limbs extended. CREDIT: Professor Yu Liu, Yunnan University.

This new specimen was nearly complete, which enabled the team to identify the six segments that made up its body: the head, a second segment with its grasping limbs, and the other four segments which have a pair of jointed limbs.

“Robert and I were examining the micro-CT data as part of his doctoral thesis in the hope of refining and correcting previous interpretation of head structures in this genus, Kylinxia,” study co-author and Yunnan Key Laboratory for Palaeobiology paleobiologist Yu Liu said in a statement. “Amazingly, we found that its head is composed of six segments, as in, e.g., insects.”

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‘Alive and wriggling’ worm survived in woman’s body and brain for at least a year https://www.popsci.com/health/roundworm-parasite-human-brain/ Tue, 29 Aug 2023 14:00:00 +0000 https://www.popsci.com/?p=566489
A magnetic resonance image of the patient’s brain by fluid-attenuated inversion recovery showing an enhancing right frontal lobe lesion (left). A live third-stage larval form of Ophidascaris robertsi removed from the patient’s right frontal lobe (right).
A magnetic resonance image of the patient’s brain by fluid-attenuated inversion recovery showing an enhancing right frontal lobe lesion (left). A live third-stage larval form of Ophidascaris robertsi removed from the patient’s right frontal lobe (right). Hossain M/Kennedy KJ/Wilson HL

The parasite and larvae known to plague pythons highlights the growing danger of zoonotic transmission.

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A magnetic resonance image of the patient’s brain by fluid-attenuated inversion recovery showing an enhancing right frontal lobe lesion (left). A live third-stage larval form of Ophidascaris robertsi removed from the patient’s right frontal lobe (right).
A magnetic resonance image of the patient’s brain by fluid-attenuated inversion recovery showing an enhancing right frontal lobe lesion (left). A live third-stage larval form of Ophidascaris robertsi removed from the patient’s right frontal lobe (right). Hossain M/Kennedy KJ/Wilson HL

A neurosurgeon in Australia pulled a live, three inch-long worm from the brain of a 64-year-old woman in June 2022. The roundworm Ophidascaris robertsi is native to Australia and its larvae were also present in other organs in the patient’s body, including the liver and lungs. This is the first known human case of this parasitic infection and it is described in a case study published in the September 2023 issue of the journal Emerging Infectious Diseases.

[Related: Rare parasites found in 200 million-year-old reptile poop.]

The patient was first admitted to her local hospital in late January 2021 after experiencing three weeks of diarrhea and abdominal pain, followed by dry cough, night sweats, and fever. By June 2022, she was also experiencing forgetfulness and depression, and was referred to Canberra Hospital. While there, she underwent brain surgery when an MRI revealed some abnormalities.

Neurosurgeon Hari Priya Bandi was performing a biopsy when she used forceps to pull the parasite out of the woman’s brain. She immediately contacted Canberra Hospital infectious diseases physician Sanjaya Senanayake, saying “Oh my god, you wouldn’t believe what I just found in this lady’s brain—and it’s alive and wriggling,” Bandi said, according to The Guardian.

According to the case study, this is the first known human Ophidascaris infection and the first to involve the brain of a mammalian species. These worms are common to carpet pythons and they typically live in a python’s stomach and esophagus. Humans infected with Ophidascaris robertsi larvae would be considered accidental parasite hosts.

“Normally the larvae from the roundworm are found in small mammals and marsupials, which are eaten by the python, allowing the life cycle to complete itself in the snake,” Senanayake, who is also one of the co-authors of the case study, said in a statement

The researchers believe that the woman from southeastern New South Wales likely caught the roundworm after collecting Warrigal greens next to a nearby lake where a python had shed the parasite via its feces. The patient used the Warrigal greens for cooking and was probably infected with the parasite directly from touching the native grass or after consuming the greens.

A live third-stage larval form of Ophidascaris robertsi that is about 3 inches long and only one millimeter in diameter. The worm is seen under a stereomicroscope.
A live third-stage larval form of Ophidascaris robertsi that is about 3 inches long and only one millimeter in diameter. The worm is seen under a stereomicroscope. CREDIT: Hossain M/Kennedy KJ/Wilson HL.

According to the team, this world-first case highlights the danger of zoonotic transmission, or  diseases and infections that pass from animals to humans. This risk is growing as humans and animals start to live more closely together and habitats continue to overlap. 

“There have been about 30 new infections in the world in the last 30 years. Of the emerging infections globally, about 75 percent are zoonotic, meaning there has been transmission from the animal world to the human world. This includes coronaviruses,” Senanayake said. “This Ophidascaris infection does not transmit between people, so it won’t cause a pandemic like SARS, COVID-19, or Ebola. However, the snake and parasite are found in other parts of the world, so it is likely that other cases will be recognised in coming years in other countries.”

[Related: Mind-controlling ‘zombie’ parasites are real.]

The patient was sent home following the surgery with antiparasitic drugs and has not returned to hospital since, but they are monitoring her since this is such a new infection.  

Despite this case being extremely rare and spine-tingling, parasitic infection is actually extremely common. One of the most widespread types is pinworm (Enterobius vermicularis or threadworm), and some estimates say it is present in over one billion people around the world. They are specific to humans and can cause intense itching and are passed from person-to-person.

Two types of hookwormNecator americanis and Ancylostoma duadonale—are found in soil. Ancylostoma duodenale only lives in Australia typically in more remote communities. These worms typically enter the bloodstream through the feet.

According to Vincent Ho, an associate professor and clinical academic gastroenterologist at Western Sydney University, the best ways to avoid a parasitic infection include avoiding undercooked or raw pork, avoiding swimming or jumping into warm fresh bodies of water, practicing good hand washing, and wearing shoes in rural areas. 

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This is how space might disturb our immune systems https://www.popsci.com/science/space-immune-system-t-cell-genes/ Tue, 29 Aug 2023 10:00:00 +0000 https://www.popsci.com/?p=566320
A close-up astronaut outside the ISS above a blue slice of Earth.
Astronauts face various health effects while in space. NASA

Microgravity can have big changes to the genes of tiny, mighty T cells.

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A close-up astronaut outside the ISS above a blue slice of Earth.
Astronauts face various health effects while in space. NASA

Outer space is a rough place for the human body. The effects of space travel on our health pose substantial challenges to our future in the cosmos. Beyond Earth, astronauts literally lose bone and muscle while being exposed to potentially cancer-causing radiation. As they plan to go on longer trips—like to the moon and Mars, such as in NASA’s Artemis program—biologists need to prepare to keep these explorers safe on these extended voyages. 

Part of that is understanding exactly how space changes our bodies, from the macroscopic scale of our organs all the way down to our microscopic cells. To that end, Swedish biologists used an experiment here on Earth to simulate what happens to a human’s immune system in microgravity, the “weightlessness” experienced by space travelers. In a new research paper, published last week in Science Advances, the study authors report significant genetic changes to these guardian cells. 

The immune system is a crucial system in the human body, protecting us from a barrage of bacteria and viruses that dwell on our lively planet. If an astronaut’s immune system is damaged by the conditions of outer space, they may not be able to fight off infections when they return to Earth, and viruses that were lingering dormant in their system might even come back with a vengeance. 

[Related: Most of us have viruses sleeping inside us, and spaceflight wakes them up]

To study this on Earth, volunteer test subjects lived in space-like conditions for 21 days, essentially floating on what are called “dry immersion” beds. Researchers analyzed the participants’ blood and found that the genes in their T cells, a type of germ-fighting white blood cell, had altered in ways that might make them less effective at protecting against pathogens.

“T cells significantly changed their gene expression—that is to say, which genes were active and which were not—after seven and 14 days of weightlessness,” says co-author Lisa Westerberg, an immunologist from Sweden’s Karolinska Institute. “T cells began to resemble more so-called naïve T cells, which have not yet encountered any intruders. This could mean that they become less effective at fighting tumor cells and infections.” 

But there’s some good news. After a return to usual gravity, some of the cells’ changes reverted back to normal, Westerberg and her colleagues observed. This suggests human bodies have the potential to re-adapt once they’re back on Earth—at least, based on this research, for 21-day trips. It’s still unclear how longer-term spaceflight, like the perilous possibly years-long journey to and from Mars, would affect astronauts, their genes, and their immune systems.

[Related: Space stations could wage war on hitchhiking bacteria with self-cleaning tech]

This isn’t the first time that scientists have noticed changes in DNA due to space travel. NASA’s famous “Twins Study”, in which astronaut Scott Kelly lived aboard the International Space Station while his twin brother Mark Kelly remained on Earth, revealed that a year in space does affect and sometimes damage genes. We also know that space can harm blood cells and bone marrow, destroying them to the point that astronauts could experience so-called “space anemia.” (Although new research shows there might be a way to combat that, using fat cells.)

The truly novel bit of this new research is how it ties cellular changes to the human body’s broader functions, allowing researchers to brainstorm fixes to the problem at a cellular level. Several clinical trials are underway for new drugs and therapies to treat similar cell-related issues on Earth, including certain cancers, allergies, and autoimmune disorders. “We therefore think this study can pave the way for new treatments that reverse these changes to the immune cells’ genetic program,” says Westerberg.

Prepping for Mars or beyond, then, has the potential to help both Earth-bound patients and spacefaring travelers, providing a better understanding of the human body no matter where it is in the universe.

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We’re finally figuring out how plants pass on genetic memories https://www.popsci.com/environment/plants-genetic-memories/ Mon, 28 Aug 2023 15:00:00 +0000 https://www.popsci.com/?p=565929
Lush and green mint leaves growing in a garden. To keep disruptive “jumping genes” quiet, some plant species use a process called methylation, which adds regulatory markers to the specific sites in the DNA and can be passed down through epigenetic memory.
To keep disruptive “jumping genes” quiet, some plant species use a process called methylation, which adds regulatory markers to the specific sites in the DNA and can be passed down through epigenetic memory. Deposit Photos

New research delves deeper into how plant proteins act like yo-yos to clear paths for important chemical markers.

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Lush and green mint leaves growing in a garden. To keep disruptive “jumping genes” quiet, some plant species use a process called methylation, which adds regulatory markers to the specific sites in the DNA and can be passed down through epigenetic memory.
To keep disruptive “jumping genes” quiet, some plant species use a process called methylation, which adds regulatory markers to the specific sites in the DNA and can be passed down through epigenetic memory. Deposit Photos

When an animal is born or when a plant sprouts, the new organism has not only inherited its parent DNA, but also some genetic memories called epigenetic memories. These genetic recollections can come in the form of a changed gene expression due to the trauma from past environmental stress or the basic instructions on how specific chemical markers in the cell should be used in the genetic code they’ve inherited. Epigenetic inheritance is particularly common in plants and understanding how it works could help produce more robust plants to secure future food supplies in the face of global climate change. 

Scientists are getting closer to understanding the processes behind epigenetic inheritance in some plants and have discovered how a specific protein works to control this process. The findings are detailed in a study published August 28 in the journal Cell

[Related: Scientists can now tell if you had a ‘vanishing’ twin in the womb.]

In the study, a team from Cold Spring Harbor Laboratory and Howard Hughes Medical Institute looked deeper into how plants pass along markers that inactivate potentially disruptive genes called transposons. Transposons are also called “jumping genes.” When they’re switched on, they can move around and disturb the other genes within a cell. To keep transposons quiet and protect the rest of the genome, cells use a process called methylation, which adds regulatory markers to the specific DNA sites where the transposons are jumping around.

During methylation, a protein that silences genes called DDM1 clears the way for the specific enzymes that place important inherited chemical markers onto a plant’s new DNA strands. Plant cells need DDM1 to clear paths because their DNA is naturally very tightly packed together. To keep the DNA properly condensed, cells wrap their DNA around packing proteins called histones

“But that blocks access to the DNA for all sorts of important enzymes,” study co-author and plant biologist Rob Martienssen said in a statement. He added that before methylation can occur, “you have to remove or slide the histones out of the way.”

A green plant with about eight leaves grows out of soil. Arabidopsis thaliana is a plant species widely used to make fundamental biological discoveries. With the help of this versatile test subject, Cold Spring Harbor Laboratory scientists have now dug up the secrets of a process that helps control inheritance. CREDIT: Martienssen Lab/Cold Spring Harbor Laboratory.
Arabidopsis thaliana is a plant species widely used to make fundamental biological discoveries. With the help of this versatile test subject, Cold Spring Harbor Laboratory scientists have now dug up the secrets of a process that helps control inheritance. CREDIT: Martienssen Lab/Cold Spring Harbor Laboratory.

This is where DDM1 works. DDM1 slides DNA along the packing proteins to expose the sites in the plant cell that need methylation. Martienssen explained that this process is like the way a yo-yo glides along a string. The histones “can move up and down the DNA, exposing parts of the DNA at a time, but never falling off,” he said.

Martienssen and former colleague Eric Richards first discovered DDM1 30 years ago and this study is building upon that initial finding using a plant called Arabidopsis thaliana or thale cress.

In a series of genetic and biochemical experiments, Martienssen pinpointed the histones that DDM1 displaces. Next, study co-author Leemor Joshua-Tor used a process called cryo-electron microscopy to take detailed images of the enzyme interacting with DNA and the packing proteins associated with it. The team saw how DDM1 grabs onto particular histones to rearrange the packaged DNA.

[Related: Dying plants are ‘screaming’ at you.]

“An unexpected bond that ties DDM1 together turned out to correspond to the first mutation found all those years ago,” molecular biologist Joshua-Tor said in a statement

Their experiments also showed how DDM1’s preference for certain histones preserves epigenetic controls across generations of plants. A histone found only in pollen is resistant to DDM1 and acts as a placeholder during cell division. “It remembers where the histone was during plant development and retains that memory into the next generation,” Martienssen said. This knowledge will help new generations of plants keep jumpy transposons from disturbing the rest of the genome. 

Plants are potentially not the only organisms performing this process. Humans also depend on proteins similar to DDM1 to maintain DNA methylation. This new understanding of its role in epigenetics could one day explain how these proteins keep our own genomes both intact and functional, but more research is needed. 

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Fossils of 10 unknown species found by sewage plant https://www.popsci.com/science/fossils-unknown-species/ Mon, 28 Aug 2023 12:00:00 +0000 https://www.popsci.com/?p=565893
A large group of white and gray fossils laid out on a blue tarp.
Some of the 266 fossil species found during a wastewater plant excavation in New Zealand. Bruce Hayward

Paleontologists sifted through thousands of 3 to 3.7 million year-old fossils in New Zealand, which also included great white shark teeth and the spine of an extinct sawshark.

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A large group of white and gray fossils laid out on a blue tarp.
Some of the 266 fossil species found during a wastewater plant excavation in New Zealand. Bruce Hayward

Fossils and ancient relics of the past turn up in some weird places, from the stretches of the New Jersey shore and random Walmarts to Swedish lakes and even the moon. They are also common finds during major excavations. More than 200 fossil species were found in a mound of sand beneath Mangere Wastewater Treatment Plant in Auckland, New Zealand.

[Related from PopSci+: The ghosts of the dinosaurs we may never discover.]

The fossils include some of the world’s oldest known flax snails, an extinct sawshark spine, great white shark teeth, and at least 10 previously known species. They are described in a study published on August 28 in the New Zealand Journal of Geology and Geophysics. According to the team, this treasure trove represents one of the richest and most diverse groups of three-million-year-old animal fossils ever found in New Zealand. 

They were first uncovered in 2020 by Watercare, Auckland’s water and wastewater service. The company was excavating two large vertical shafts as part of an upgrade to the major pipeline that brings raw sewage from the center of the city to a plant for treatment. While digging, they came upon the ancient shell bed dating back at least three million years. Geologist and study co-author Bruce Hayward from Auckland-based research group Geomarine Research said that the discovery was similar to “finding gold right on your doorstep.”

Watercare and their contractors brought the shelly sand over to a nearby field so that Hayward and a team of paleontologists led by Auckland Museum curator Wilma Blom could carefully sift through it. The team examined more than 300,000 fossils of 266 species, and several thousand specimens have been brought to this museum.

The fossils were likely deposited between 3 and 3.7 million years ago into a subtidal channel that would become present-day Manukau Harbour. “At that time, sea level was slightly higher than it is today as the world was also several degrees warmer than now,” Hayward said in a statement. “As a result, the fossils include a number of subtropical species, whose relatives today live in the warmer waters around the Kermadec and Norfolk islands.”

In the study, the team describes 266 different fossil species and some rare finds, including a baleen whale vertebrae, dental plates of eagle rays, and a broken sperm whale tooth. The roughly 10 previously unknown species described and named in future research. 

[Related: Fossil trove in Wales is a 462-million-year-old world of wee sea creatures.]

One aspect of this fossil bed that surprised the team is that the fossilized remains belong to animals that lived in many different environments that were eventually brought together in the ancient marine channel through strong currents and waves. Ten specimens of an iconic  mollusk called the New Zealand flax snail likely lived on the land next to the ancient subtidal channel and were washed out to sea by storm runoff, according to the team. Other specimens were likely attached to hard rocky shorelines, while others were washed into the channel from areas further offshore.  

The team dedicated the work to New Zealand’s leading molluscan fossil expert Alan Beu, who was working on the fossils before he died earlier this year.

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The largest search of Loch Ness in more than 50 years will deploy drones and hydrophones https://www.popsci.com/technology/loch-ness-exploration/ Thu, 24 Aug 2023 16:30:00 +0000 https://www.popsci.com/?p=565302
Famous, debunked black and white 'Surgeon's Photo' of Loch Ness Monster
The famous 1934 'Surgeon's Photo' of the 'Loch Ness Monster' was later proven to be a hoax. Keystone/Getty

Enthusiasts will use thermal imaging and underwater listening devices to search for "Nessie."

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Famous, debunked black and white 'Surgeon's Photo' of Loch Ness Monster
The famous 1934 'Surgeon's Photo' of the 'Loch Ness Monster' was later proven to be a hoax. Keystone/Getty

The largest cryptological survey of Loch Ness in over 50 years is scheduled to take place this weekend, featuring technology never before used to search for the elusive, still unproven Loch Ness Monster. Affectionately known by many as “Nessie,” no physical evidence of the cryptid—a creature whose existence isn’t proven by science or biology—has ever been found. The expedition is sponsored by the “independent and voluntary research team,” Loch Ness Exploration (LNE), an organization that is currently seeking additional help from the public in conducting a “giant surface watch” of the loch’s waters. Although an “overwhelming” demand has already resulted in sold out in-person spots, those who can’t make it over to Scotland can still tune in to LNE’s official 24/7 live stream to help out organizers.

“Since starting LNE, it’s always been our goal to record, study and analyze all manner of natural behavior and phenomena that may be more challenging to explain,” Alan McKenna, LNE founder, said in a statement earlier this month. “It’s our hope to inspire a new generation of Loch Ness enthusiasts and by joining this large scale surface watch… to personally contribute towards this fascinating mystery that has captivated so many people from around the world.”

[Related: New DNA evidence may prove what the Loch Ness Monster really is.]

Alleged sightings of the supposed lake monster (or monsters) in Loch Ness date back centuries, but the tales particularly rose to global attention after the famous 1934 “Surgeon’s Photo.” Although the iconic silhouette was later proved a hoax, folklore surrounding a large aquatic creature lurking within the loch remains strong. In 2019, samples taken from the nearly 22-square-mile body of water indicated the prevalence of eel DNA, potentially providing an explanation for at least some of visitors’ sightings over the decades. The collected DNA, however, did not indicate an eel’s size, thus adding little support to a “giant eel” theory. Of course, many still hold out hope for the possibility of a somehow still undiscovered pod of plesiosaurs calling Loch Ness home.

On August 26 and 27, however, the LNE team will deploy at least a few new tools in hopes of uncovering evidence of something strange. According to the event’s announcement page, drones will traverse the loch while taking thermal imaging of the waters via infrared cameras, potentially “identifying any mysterious anomalies.” Meanwhile, researchers will repeatedly deploy an underwater hydrophone to listen in on any “Nessie-like calls.”

“The weekend gives an opportunity to search the waters in a way that has never been done before, and we can’t wait to see what we find,” said Loch Ness Centre general manager, Paul Nixon. 

Of course, the odds aren’t exactly in Nessie volunteers’ favor following decades of debunks, hoaxes, and misattributed sightings. Still, it’s probably as nice a time of the year as any to get out onto the loch and enjoy the Scottish summer.

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The final missing piece of the human genome has been decoded https://www.popsci.com/science/human-y-chromosome-full-sequence/ Wed, 23 Aug 2023 19:32:00 +0000 https://www.popsci.com/?p=564923
Purple and blue visualizations of human chromosomes.
It took roughly 100 years to fill in all the missing details of the Y chromosome. Darryl Leja, National Human Genome Research Institute, NIH

Mysteries hidden in the human Y chromosomes are now coming to light.

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Purple and blue visualizations of human chromosomes.
It took roughly 100 years to fill in all the missing details of the Y chromosome. Darryl Leja, National Human Genome Research Institute, NIH

Despite its macho connotations, the Y chromosome is among the tiniest of the 46 chromosomes in the human genome. It makes up only 2 percent of a human cell’s total DNA. But because of its seemingly endless repeating bases, the Y chromosome is one of the most difficult to genetically sequence. Scientists initially believed it was nothing more than a genetic wasteland, only good for making sperm.

Yet, in reality, that’s not the case at all. As genetic technology grows more advanced, so has our understanding of the Y chromosome’s importance. Its loss in older men, for example, is associated with an increased risk of cancer and other chronic diseases. Its genes somehow play a part in multiple biological processes. But, for decades, more than half of the Y chromosome remained unsequenced, and its role in human health remained a mystery.

That age of mystery is ending. For the first time, geneticists have assembled a complete sequence of the Y chromosome. The international Telomere-to-Telomere (T2T) Consortium added data for more than 30 million new base pairs and identified 41 new protein-coding genes. Two studies published today in Nature break down those findings, explaining how this chromosome affects our reproduction, evolution, and even the gut microbiome.

[Related: What we might learn about embryos and evolution from the most complete human genome map yet]

“The complete sequence of the Y chromosome has opened up a lot of doors for the scientific community,” says Chris Lau, a professor of medicine at the University of California, San Francisco who studies the human Y chromosome but was not involved in these current studies. “We anticipate some surprises could be forthcoming, just like the time in the past we thought it was full of junk materials.”

A picture a century in the making

It took more than 100 years for biologists to construct a complete assembly of the Y chromosome’s structure, after its discovery in 1905. The first human genome was completed in April 2003, but it left behind some unknown gaps, including swathes of the Y chromosome. 

The chromosome’s repetition made it a challenge to reconstruct. It has more than a million of base pairs lined up in long repeated sequences, says Karen Miga, the associate director at the University of California, Santa Cruz Genomics Institute and co-lead of the T2T Consortium. These are known as palindromes, because they are the same from front to back. 

The Y chromosome is among the tiniest of these 46 paired structures.
The Y chromosome is among the tiniest of these 46 paired structures. National Human Genome Research Institute

All chromosomes have some repeats in their genes, but the Y chromosome has an unusually high amount. Assembling these was a laborious and expensive process. “Researchers have had a hard time studying this in the past because we just didn’t have the right tools to reconstruct these really complex repeats,” Miga says. 

New advances in long-read sequencing technology and computational assembly methods made it easier to put each repetitive sequence in order. For example, the team could now identify exactly where an inversion occurs—where breaks in the DNA cause a segment to reinsert itself in reverse order—and use that technique to spot other inversions. 

Filling in millions of blanks

The new techniques added more than 30 million base pairs missing from the current Human Genome Project, for a grand total of 62,460,029 base pairs in the Y chromosome. The Y chromosome shows to have a unique organization of DNA sequences that’s strangely not seen in other chromosomes, Miga says. She believes a ton of new biology is required to understand the evolutionary reason behind this organization and how parts of the chromosome correspond to human function. 

[Related: We’re one step closer to identifying the first-ever mammals]

The research team has already made some headway in reshaping science. These newly discovered sequences corrected several mistakes and assumptions found in the human genome reference sequence. They’ve also provided new insight into the ways the Y chromosome shapes human life.

“This is an extremely important finding in the human genome field,” Lau says.

Fertility and proteins

The Y chromosome contains many genes that regulate the production of sperm. Some of these newfound repetitive genomic regions, according to Miga, play a part in that process, too. “Understanding differences that could exist between humans could really inform things like infertility and how that process is inherited across time.”

Sequencing the Y chromosome also revealed 41 new protein-coding genes, 38 of which were extra copies of a gene family called TSPY, thought to be involved in sperm production. It’s possible they are also responsible for the development of male sex characteristics, but more research is needed to determine their precise roles. 

Variation in human evolution

Commercial ancestry sites use Y chromosomes to trace paternal lineages. The new DNA sequences can further help researchers understand how humans evolved over time. In the second study, geneticists examined the Y chromosomes from 43 genetically diverse men. They found significant amounts of genetic variation between individuals. 

In some parts of the chromosome, its component parts—nucleotides—were very similar across the men. But half of gene-rich regions in the Y chromosomes had greater mutation rates carrying large inversions, at a higher rate than most other parts of the genome. These differences in genetic variation could have potentially evolved to hold some important biological function, though what that could be is unknown. 

Correcting bacterial confusion

When analyzing genetic samples, researchers often use databases to screen for sequences belonging to human DNA. If the sequences aren’t found anywhere in the current model of the human genome, scientists are likely to conclude the material belongs to bacteria. The new studies show some Y chromosome sequences, not yet entered in human databases, were mislabeled as bacteria.

Not junk after all

Geneticists will continue to mine discoveries from this treasure trove of data. Further analyses of the Y chromosome are likely to clarify the relevance of this chromosome in human health and disease.
This information “will benefit research in human evolution and migration, forensic science, and many translational applications in diagnostic and prognostic development in human diseases,” Lau says, “particularly the scientific reason for the mosaic loss of the Y chromosome in disease and cancer among others.”

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Hogfish ‘see’ using their skin https://www.popsci.com/environment/hogfish-skin-vision/ Wed, 23 Aug 2023 14:00:00 +0000 https://www.popsci.com/?p=564665
A hogfish swims near the Florida Keys. It has spikes on top and a pointy snout.
Hogfish are found in the western Atlantic Ocean and carry a gene for a light-sensitive protein called opsin. Deposit Photos

These chameleons of the sea can change color in milliseconds.

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A hogfish swims near the Florida Keys. It has spikes on top and a pointy snout.
Hogfish are found in the western Atlantic Ocean and carry a gene for a light-sensitive protein called opsin. Deposit Photos

The pointy-snouted and reef dwelling hogfish that dot the Atlantic Ocean between North Carolina and Brazil are known for their color-changing skin. These chameleons of the sea can quickly switch from white to a reddish brown to blend in with reefs, but their skin may be hiding something else.

[Related: Octopus change color as they shift between sleep phases.]

A study published August 21 in the journal Nature Communications looked deeper into the hogfish’s sensory feedback system and found that the fish could be using their skin to help see underwater. They can also use this to take mental photographs of themselves from the inside.

University of North Carolina Wilmington biologist Lori Schweikert was inspired to study this phenomenon after she witnessed it first hand in the Florida Keys. When she saw that a hogfish could continue this camouflage act even after it had died, she wondered if hogfish could detect light using only their skin, versus relying on their eyes and brain. 

In an earlier study, Schweikert and Duke University biologist Sönke Johnsen found that hogfish carry a gene for a light-sensitive protein called opsin that is activated in their skin. This gene is different from the opsin genes that are found in their eyes. Squid, geckos, and other color-changing animals also make light-sensing opsins in their skin, but scientists are unsure how they help the animals change color. One hypothesis is that light-sensing skin helps animals take in their surroundings, but it also could be a way that the animals view themselves. 

In this new study, Schweikert and Johnsen took pieces of skin from different parts of the hogfish’s body and took images of them under a microscope. Up close, each dot of color on the skin is a specialized cell called a chromatophore. These cells have granules of pigment inside them that can be black, yellow, or red.

The movement of these pigment granules changes the skin color. When they are spread out across the cell, darker colors appear. The cell becomes more transparent when they cluster together into a tiny spot. 

Fish photo
Seen through a microscope, a hogfish’s skin looks like a pointillist painting. Each dot of color is a specialized cell containing pigment granules that can be red, yellow or black. The pigment granules can spread out or cluster tightly together within the cell, making the color appear darker or more transparent. CREDIT: Lori Schweikert, University of North Carolina Wilmington

Next, the team used a technique called immunolabeling to find the light sensing opsin proteins within the skin. They saw that in hogfish, the opsins aren’t produced in the color-changing chromatophore cells. The opsins actually reside in other cells that are located directly beneath them.

Images taken with a transmission electron microscope showed a previously unknown cell type below the chromatophores that are full of opsin protein.

[Related: Some sea snakes may not be colorblind after all.]

According to Schweikert, the light striking the skin must pass through the pigment-filled chromatophores first before it gets to the light-sensitive layer. She and the team estimate that the opsin molecules in the hogfish are most sensitive to blue light. This is the wavelength of light that the pigment granules in the hogfish absorb best. 

The fish’s light-sensitive opsins are somewhat like an internal roll of Polaroid film, that captures changes in the light and then can filter through the pigment-filled cells when the pigment granules fan out or scrunch up. 

“The animals can literally take a photo of their own skin from the inside,” Johnsen said in a statement. “In a way they can tell the animal what its skin looks like, since it can’t really bend over to look.”

Eyes do more than merely detect light and work to form images, so it’s not enough to say that hogfish skin is like a giant eye. 

“Just to be clear, we’re not arguing that hogfish skin functions like an eye,” Schweikert added in a statement. “We don’t have any evidence to suggest that’s what’s happening in their skin. They appear to be watching their own color change.”

The findings may help researchers develop better sensory feedback techniques for devices that need to fine-tune performance without eyesight or camera feeds, such as robotic limbs and self-driving cars.

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