By Claudia López Lloreda Genetic tweaks in kingfishers might help cushion the blow when the diving birds plunge beak first into the water to catch fish. Analysis of the genetic instruction book of some diving kingfishers identified changes in genes related to brain function as well as retina and blood vessel development, which might protect against damage during dives, researchers report October 24 in Communications Biology. The results suggest the different species of diving kingfishers may have adapted to survive their dives unscathed in some of the same ways, but it’s still unclear how the genetic changes protect the birds. Hitting speeds of up to 40 kilometers per hour, kingfisher dives put huge amounts of potentially damaging pressure on the birds’ heads, beaks and brains. The birds dive repeatedly, smacking their heads into the water in ways that could cause concussions in humans, says Shannon Hackett, an evolutionary biologist and curator at the Field Museum in Chicago. “So there has to be something that protects them from the terrible consequences of repeatedly hitting their heads against a hard substrate.” Hackett first became interested in how the birds protect their brains while she worked with her son’s hockey team and started worrying about the effect of repeated hits on the human brain. Around the same time, evolutionary biologist Chad Eliason joined the museum to study kingfishers and their plunge diving behavior. In the new study, Hackett, Eliason and colleagues analyzed the complete genome of 30 kingfisher species, some that plunge dive and others that don’t, from specimens frozen and stored at the museum. The preserved birds came from all over the world; some of the diving species came from mainland areas and others from islands and had evolved to dive independently rather than from the same plunge-diving ancestor. The team wanted to know if the different diving species had evolved similar genetic changes to arrive at the same behaviors. Many kingfisher species have developed this behavior, but it was unclear whether this was through genetic convergence, similar to how many species of birds have lost their flight or how bats and dolphins independently developed echolocation (SN: 9/6/2013). © Society for Science & the Public 2000–2023.

Keyword: Brain Injury/Concussion; Evolution
Link ID: 28991 - Posted: 11.08.2023

By Darren Incorvaia The idea of a chicken running around with its head cut off, inspired by a real-life story, may make it seem like the bird doesn’t have much going on upstairs. But Sonja Hillemacher, an animal behavior researcher at the University of Bonn in Germany, always knew that chickens were more than mindless sources of wings and nuggets. “They are way smarter than you think,” Ms. Hillemacher said. Now, in a study published in the journal PLOS One on Wednesday, Ms. Hillemacher and her colleagues say they have found evidence that roosters can recognize themselves in mirrors. In addition to shedding new light on chicken intellect, the researchers hope that their experiment can prompt re-evaluations of the smarts of other animals. The mirror test is a common, but contested, test of self-awareness. It was introduced by the psychologist Gordon Gallup in 1970. He housed chimpanzees with mirrors and then marked their faces with red dye. The chimps didn’t seem to notice until they could see their reflections, and then they began inspecting and touching the marked spot on their faces, suggesting that they recognized themselves in the mirror. The mirror test has since been used to assess self-recognition in many other species. But only a few — such as dolphins and elephants — have passed. After being piloted on primates, the mirror test was “somehow sealed in a nearly magical way as sacred,” said Onur Güntürkün, a neuroscientist at Ruhr University Bochum in Germany and an author of the study who worked with Ms. Hillemacher and Inga Tiemann, also at the University of Bonn. But different cognitive processes are active in different situations, and there’s no reason to think that the mirror test is accurate for animals with vastly different sensory abilities and social systems than what chimps have. The roosters failed the classic mirror test. When the team marked them with pink powder, the birds showed no inclination to inspect or touch the smudge in front of the mirror the way that Dr. Gallup’s chimps did. As an alternative, the team tested rooster self-awareness in a more fowl friendly way. © 2023 The New York Times Company

Keyword: Consciousness; Intelligence
Link ID: 28978 - Posted: 10.28.2023

By Christa Lesté-Lasserre A gray cat stares quietly at a nearby orange tabby, squinting her eyes, flattening her ears, and licking her lips. The tabby glares back, wrinkles his nose, and pulls back his whiskers. Cat people know what’s about to go down: a fight. If looks and growls don’t resolve the budding tiff, claws will pop out and fur will fly. Those faces aren’t the only ones cats make at each other, of course—not by a long shot. In a study published this month in Behavioural Processes, researchers tallied 276 different feline facial expressions, used to communicate hostile and friendly intent and everything in between. What’s more, the team found, we humans might be to thank: Our feline friends may have evolved this range of sneers, smiles, and grimaces over the course of their 10,000-year history with us. “Many people still consider cats—erroneously—to be a largely nonsocial species,” says Daniel Mills, a veterinary behaviorist at the University of Lincoln who was not involved in the study. The facial expressions described in the new study suggest otherwise, he notes. “There is clearly a lot going on that we are not aware of.” Cats can be solitary creatures, but they often form friendships with fellow kitties in people’s homes or on the street; feral cats can live in colonies of thousands, sometimes taking over entire islands. Lauren Scott, a medical student and self-described cat person at the University of Kansas, long wondered how all these felines communicated with one another. There has to be love and diplomacy, not just fighting, yet most studies of feline expression have focused on aggression. Fortunately in 2021, Scott was studying at the University of California, Los Angeles (UCLA), just minutes from the CatCafé Lounge. There, human visitors can interact—and even do yoga—with dozens of group-housed, adoptable cats. From August to June, Scott video recorded 194 minutes of cats’ facial expressions, specifically those aimed at other cats, after the café had closed for the day. Then she and evolutionary psychologist Brittany Florkiewicz, also at UCLA at the time but now at Lyon College, coded all their facial muscle movements—excluding any related to breathing, chewing, yawning, and the like.

Keyword: Emotions; Evolution
Link ID: 28977 - Posted: 10.28.2023

By Bruce Bower Female chimps living in an East African forest experience menopause and then survive years, even decades, after becoming biologically unable to reproduce. The apes are the first known examples of wild, nonhuman primates to go through the fertility-squelching hormonal changes and live well beyond their reproductive years. The finding raises new questions about how menopause evolved, UCLA evolutionary anthropologist Brian Wood and colleagues conclude in the Oct. 27 Science. Until now, females who experience menopause and keep living for years have been documented only in humans and five whale species. It’s unclear what evolutionary benefit exists to explain such longevity past the point of being able to give birth and pass on one’s genes. Although evolutionary explanations for menopause remain debatable, the new finding reflects an especially close genetic relationship between humans and chimps, Wood says. “Both [species] are more predisposed to post-reproductive survival than other great apes.” Some evidence suggests that female fertility ends at similar ages in humans and chimps (Pan troglodytes) if our ape relatives live long enough, says anthropologist Kristen Hawkes of the University of Utah in Salt Lake City. But in other studies, female chimps, such as those studied by Jane Goodall at Tanzania’s Gombe National Park starting in 1960, aged quickly and often died in their early 30s, usually while still having menstrual cycles, she says. “What’s surprising [in Wood’s study] is so many females living so long after menopause,” Hawkes says. © Society for Science & the Public 2000–2023.

Keyword: Hormones & Behavior; Evolution
Link ID: 28975 - Posted: 10.28.2023

Christie Wilcox Adult horsehair worms look about how you’d expect given their name: They’re long, noodlelike creatures that resemble wiggling horse hairs. They live and reproduce in water, but their young only develop inside the bodies of other animals—usually terrestrial insects such as praying mantises. Once they’ve finished growing inside their unwitting vessel, the worms must convince their hosts to drown themselves to complete their life cycle. How these parasites manage to lethally manipulate their hosts has long puzzled scientists. Researchers behind a new study published today in Current Biology suggest horsehair worms possess hundreds of genes that allow them to hijack a mantis’ movement—and they may have acquired these genes directly from their ill-fated hosts. “The results are amazing,” says Clément Gilbert, an evolutionary biologist at the University of Paris-Saclay who wasn’t involved in the work. If it turns out to be true that so many of the mantises’ genes jumped over to the parasitic worms—a process known as horizontal gene transfer—then “this is by far the highest number of horizontally transferred genes that have been reported between two species of animals,” he adds. The phenomenon of parasites mind-controlling their hosts to an early grave has always intrigued Tappei Mishina, an evolutionary biologist at Kyushu University and the RIKEN Center for Biosystems Dynamics Research. “For more than 100 years, there have been horrifying observations of terrestrial insects jumping into water right before our eyes all over the world,” he says. He teamed up with ecologist Takuya Sato of the Center for Ecological Research at Kyoto University to investigate the genetic basis of their parasitism. They focused on horsehair or gordian worms, a group of parasitic animals related to nematodes. Many have complex life cycles involving multiple hosts, and the ones that live in freshwater must generally find their way into an insect to finish developing into adults. The genus Mishina, Sato, and their colleagues specialize in, known as Chordodes, infect mantises and can grow to nearly 1 meter long inside the palm-size insects’ abdomens.

Keyword: Genes & Behavior; Evolution
Link ID: 28971 - Posted: 10.25.2023

By Tim Vernimmen For humans, division of labor has become a necessity: No person in the world has all the knowledge and skills to perform all the tasks that are required to keep our highly technological societies afloat. This has made us entirely dependent on each other, leaving us individually vulnerable. We really can’t make it on our own. From archaeological findings, we can reconstruct more or less how this situation evolved. Initially, everyone was doing more or less the same thing. But because food was shared among people living in hunter-gatherer groups, some were able to specialize in tasks other than finding food, such as fashioning tools, treating illnesses or cultivating plants. These skills enriched the group but made the specialists even more dependent on others. This further reinforced cooperation among group members and pushed our species to even higher levels of specialization — and prosperity. “Societies that have highly developed task-sharing and division of labor between group members are conspicuous because of their exceptional ecological success,” says Michael Taborsky, a behavioral biologist at the University of Bern in Switzerland. And he doesn’t just mean us: Extensive division of labor also can be seen among many social insects — ants, wasps, bees and termites — in which individuals in large colonies often specialize in particular tasks, making them impressively effective. “It is no exaggeration,” Taborsky says, “to say that societies” — of both humans and social insects — “predominate life on Earth.” But how did this division of labor evolve? Why does it seem to be rare outside of our species and the social insects? Is it, in fact, as rare as it seems? Taborsky, who has studied cooperation in animals for decades, has become increasingly interested in these questions. In March 2023, he and Barbara Taborsky, his wife and colleague, organized a scientific workshop on the topic in Berlin to which they invited a number of other experts. Over the course of two days, the group discussed how division of labor may have evolved over time, and what mechanisms allow it to develop, over and over again, in every colony of certain species. One of the invited scientists was Jennifer Fewell, a social insect biologist at Arizona State University who coauthored an influential overview of division of labor in the Annual Review of Entomology in 2001 and has studied the subject for decades. In social insect colonies, she says, “there is no central controller telling everybody what to do, but instead, the division of labor emerges from the interaction between individuals.” © 2023 Annual Reviews

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 28944 - Posted: 10.05.2023

By Carl Zimmer In more than 1,500 animal species, from crickets and sea urchins to bottlenose dolphins and bonobos, scientists have observed sexual encounters between members of the same sex. Some researchers have proposed that this behavior has existed since the dawn of the animal kingdom. But the authors of a new study of thousands of mammalian species paint a different picture, arguing that same-sex sexual behavior evolved when mammals started living in social groups. Although the behavior does not produce offspring to carry on the animals’ genes, it could offer other evolutionary advantages, such as smoothing over conflicts, the researchers proposed. “It may contribute to establishing and maintaining positive social relationships,” said José Gómez, an evolutionary biologist at the Experimental Station of Arid Zones in Almería, Spain, and an author of the new study. But Dr. Gómez cautioned that the study, published on Tuesday in the journal Nature Communications, could not shed much light on sexual orientation in humans. “The type of same-sex sexual behavior we have used in our analysis is so different from that observed in humans that our study is unable to provide an explanation for its expression today,” he said. Previous studies of same-sex sexual behavior have typically involved careful observations of a single species, or a small group of them. Dr. Gómez and his colleagues instead looked for the big evolutionary patterns that gave rise to the behavior in some species but not others. The researchers surveyed the 6,649 species of living mammals that arose from reptilelike ancestors starting roughly 250 million years ago. Looking over the scientific literature, they noted which of them had been seen carrying out same-sex sexual behaviors — defined as anything from courtships and mating to forming long-term bonds. The researchers ended up with a list of 261 species, or about 4 percent of all mammalian species, that exhibited these same-sex behaviors. Males and females were about equally likely to be observed carrying out same-sex sexual behavior, the analysis showed. In some species, only one sex did. But in still others — including cheetahs and white-tailed deer — both males and females engaged in same-sex sexual behavior. © 2023 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 28943 - Posted: 10.05.2023

By Katherine Harmon Courage On the surface, sleep seems obvious, essential. It comes in long, languid, predictable waves, washing over humans and elephants, birds and fish and beetles. It comes bearing restoration, repair, learning. It follows an ancestral rhythm played deep within our cells, cued by the movement of our planet around our star. Perhaps we could believe this nice, simple fantasy, were it not for an irksome little eyeless fish. More than a decade ago, this fish—the Mexican tetra (Astyanax mexicanus)—caught the eye of a graduate student at New York University. It was not new to science—it had been the subject of fascination for aquarists and researchers for decades, who marveled at its ghostly appearance and the splash of skin where its eyes should have been. But other quirks of the fish turned out to be even more mysterious. In Manhattan, the fish were far from their place of origin: a collection of unassuming caves strung through northeastern Mexico. Inside these caves, it is pitch dark, always cool, quiet, and rather boring. A seemingly perfect place to sleep. So Erik Duboué, the curious graduate student, decided to test if these fish showed any unusual sleep habits. One night in 2009, he made a 2 a.m. visit to the lab and noticed something strange about these sightless fish: They seemed wide awake. On further investigation, he found that despite their soporific native environs, they actually hardly sleep at all. In fact, he discovered, they doze just about three and a half hours out of each 24-hour period. And their bouts of sleep seem to come on entirely randomly and only in brief spurts. Curiously, these eyeless cavefish seem to have been flourishing on this quiescence interruptus for hundreds of thousands of years. “What you have is a fish that is completely healthy—it just doesn’t need to sleep,” says Duboué, who is now a molecular geneticist at Florida Atlantic University. Since then, Duboué and others have been studying the strange sleep of these wakeful creatures—prodding them in the lab to rouse them from their occasional slumber and plumbing their DNA. Combined with investigations into other animals, as well as some peculiar experiments that have sent humans to sleep in caves, scientists are uncovering new, closely guarded truths about sleep that have eluded us in our bright, rhythmic world. © 2023 NautilusNext Inc.

Keyword: Sleep; Evolution
Link ID: 28941 - Posted: 10.03.2023

By Veronique Greenwood In the dappled sunlit waters of Caribbean mangrove forests, tiny box jellyfish bob in and out of the shade. Box jellies are distinguished from true jellyfish in part by their complex visual system — the grape-size predators have 24 eyes. But like other jellyfish, they are brainless, controlling their cube-shaped bodies with a distributed network of neurons. That network, it turns out, is more sophisticated than you might assume. On Friday, researchers published a report in the journal Current Biology indicating that the box jellyfish species Tripedalia cystophora have the ability to learn. Because box jellyfish diverged from our part of the animal kingdom long ago, understanding their cognitive abilities could help scientists trace the evolution of learning. The tricky part about studying learning in box jellies was finding an everyday behavior that scientists could train the creatures to perform in the lab. Anders Garm, a biologist at the University of Copenhagen and an author of the new paper, said his team decided to focus on a swift about-face that box jellies execute when they are about to hit a mangrove root. These roots rise through the water like black towers, while the water around them appears pale by comparison. But the contrast between the two can change from day to day, as silt clouds the water and makes it more difficult to tell how far away a root is. How do box jellies tell when they are getting too close? “The hypothesis was, they need to learn this,” Dr. Garm said. “When they come back to these habitats, they have to learn, how is today’s water quality? How is the contrast changing today?” In the lab, researchers produced images of alternating dark and light stripes, representing the mangrove roots and water, and used them to line the insides of buckets about six inches wide. When the stripes were a stark black and white, representing optimum water clarity, box jellies never got close to the bucket walls. With less contrast between the stripes, however, box jellies immediately began to run into them. This was the scientists’ chance to see if they would learn. © 2023 The New York Times Company

Keyword: Learning & Memory; Evolution
Link ID: 28925 - Posted: 09.23.2023

By Till Hein Human couples could learn a lot from seahorses. The marine marvels spend only quality time together. They flirt, swim together, and mate. The rest of time they go their own way, drifting in ocean currents, leisurely eating their fill. But they do look forward to getting together again. Right after sunrise, male and female seahorses approach one another, gently rubbing their noses together and then begin to circle each other. Many of them make seductive clicking noises. The partners gracefully rock back and forth, as though to the beat of underwater music. They dance and cuddle together dreamily, as though they’ve lost track of time. However, love can be dangerous for seahorses. During partner dancing, hormones are released that can make their camouflage fade. This causes changes in color, so their bodies begin to glow, and the contrasts in the patterns of their skin become more pronounced. Researchers hypothesize this is how seahorses signal their willingness to mate. The partner dances also serve as a means of seduction. Before mating, courtship can take many hours. Finally, the female signals that she’s ready. She swims up toward the water surface, pointing her snout toward the sky, and stretches her body out straight as a stick—a pose that is irresistible to the male. The stallion of the sea presses his chin against his chest and makes his prehensile tail open and close like a switchblade. This enables him to pump water into his brood pouch to show his beloved mare of the sea how roomy it is. Soon afterward, the mare and stallion of the sea snuggle up together closely and let themselves drift upward. They press their bodies together so that their snouts and abdomens are touching. On account of the curves in their body posture, the space between them looks like the shape of a heart. Then, something amazing takes place. A tubular rod appears in the middle of the female seahorse’s belly, which looks a little like a penis, the so-called ovipositor. At the climax of the love scene, both partners lift their heads as though in ecstasy, curving their backs, and the female seahorse transfers her eggs into the male’s brood pouch, while her partner fertilizes them with his sperm. © 2023 NautilusNext Inc., All rights reserved.

Keyword: Sexual Behavior; Evolution
Link ID: 28923 - Posted: 09.23.2023

By Sonia Shah Can a mouse learn a new song? Such a question might seem whimsical. Though humans have lived alongside mice for at least 15,000 years, few of us have ever heard mice sing, because they do so in frequencies beyond the range detectable by human hearing. As pups, their high-pitched songs alert their mothers to their whereabouts; as adults, they sing in ultrasound to woo one another. For decades, researchers considered mouse songs instinctual, the fixed tunes of a windup music box, rather than the mutable expressions of individual minds. But no one had tested whether that was really true. In 2012, a team of neurobiologists at Duke University, led by Erich Jarvis, a neuroscientist who studies vocal learning, designed an experiment to find out. The team surgically deafened five mice and recorded their songs in a mouse-size sound studio, tricked out with infrared cameras and microphones. They then compared sonograms of the songs of deafened mice with those of hearing mice. If the mouse songs were innate, as long presumed, the surgical alteration would make no difference at all. Jarvis and his researchers slowed down the tempo and shifted the pitch of the recordings, so that they could hear the songs with their own ears. Those of the intact mice sounded “remarkably similar to some bird songs,” Jarvis wrote in a 2013 paper that described the experiment, with whistlelike syllables similar to those in the songs of canaries and the trills of dolphins. Not so the songs of the deafened mice: Deprived of auditory feedback, their songs became degraded, rendering them nearly unrecognizable. They sounded, the scientists noted, like “squawks and screams.” Not only did the tunes of a mouse depend on its ability to hear itself and others, but also, as the team found in another experiment, a male mouse could alter the pitch of its song to compete with other male mice for female attention. Inside these murine skills lay clues to a puzzle many have called “the hardest problem in science”: the origins of language. In humans, “vocal learning” is understood as a skill critical to spoken language. Researchers had already discovered the capacity for vocal learning in species other than humans, including in songbirds, hummingbirds, parrots, cetaceans such as dolphins and whales, pinnipeds such as seals, elephants and bats. But given the centuries-old idea that a deep chasm separated human language from animal communications, most scientists understood the vocal learning abilities of other species as unrelated to our own — as evolutionarily divergent as the wing of a bat is to that of a bee. The apparent absence of intermediate forms of language — say, a talking animal — left the question of how language evolved resistant to empirical inquiry. © 2023 The New York Times Company

Keyword: Language; Animal Communication
Link ID: 28921 - Posted: 09.21.2023

COMIC: When, why and how did neurons first evolve? Scientists are piecing together the ancient story. By Tim Vernimmen Illustrated by Maki Naro 09.14.2023 © 2023 Annual Reviews

Keyword: Evolution; Development of the Brain
Link ID: 28920 - Posted: 09.21.2023

By Kenneth S. Kosik Before our evolutionary ancestors had a brain—before they had any organs—18 different cell types got together to make a sea sponge. Remarkably, some of these cells had many of the genes needed to make a brain, even though the sponge has neither neurons nor a brain. In my neuroscience lab at the University of California, Santa Barbara, my colleagues and collaborators discovered this large repository of brain genes in the sponge. Ever since, we have asked ourselves why this ancient, porous blob of cells would contain a set of neural genes in the absence of a nervous system? What was evolution up to? The sea sponge first shows up in the fossil record about 600 million years ago. They live at the bottom of the ocean and are immobile, passive feeders. In fact, early biologists thought they were plants. Often encased by a hard exterior, a row of cells borders a watery center. Each cell has a tiny cilium that gently circulates a rich flow of microorganisms on which they feed. This seemingly simple organization belies a giant step in evolution. For the previous 3 billion years, single-celled creatures inhabited the planet. In one of evolution’s most creative acts, independent cells joined together, first into a colony and later into a truly inseparable multicellular organism. Colonies of single cells offered the first inkling that not every cell in the colony had to be identical. Cells in the interior might differ subtly from those on the periphery that are subject to the whims of the environment. Colonies offered the advantages of cooperation among many nearly identical cells. The next evolutionary innovation, multicellularity, broke radically from the past. © 2023 NautilusNext Inc.,

Keyword: Evolution
Link ID: 28913 - Posted: 09.16.2023

By Darren Incorvaia By now, it’s no secret that the phrase “bird brain” should be a compliment, not an insult. Some of our feathered friends are capable of complex cognitive tasks, including tool use (SN: 2/10/23). Among the brainiest feats that birds are capable of is vocal learning, or the ability to learn to mimic sounds and use them to communicate. In birds, this leads to beautiful calls and songs; in humans, it leads to language. The best avian vocal learners, such as crows and parrots, also tend to be considered the most intelligent birds. So it’s natural to think that the two traits could be linked. But studies with smart birds have found conflicting evidence. Although vocal learning may be linked with greater cognitive capacity in some species, the opposite relationship seems to hold true in others. Now, a massive analysis of 214 birds from 23 species shows that there is indeed a link between vocal learning and at least one advanced cognitive ability — problem-solving. The study, described in the Sept. 15 Science, is the first to analyze multiple bird species instead of just one. More than 200 birds from 23 species were given different cognitive tests to gauge their intelligence. One of the problem-solving tasks asked birds to pull a cork lid off a glass flask to access a tasty treat (bottom left). Comparing these tests with birds’ ability to learn songs and calls showed that the better vocal learners are also better at problem-solving. To compare species, biologist Jean-Nicolas Audet of the Rockefeller University in New York City and colleagues had to devise a way to assess all the birds’ vocal learning and cognitive abilities. © Society for Science & the Public 2000–2023.

Keyword: Intelligence; Evolution
Link ID: 28912 - Posted: 09.16.2023

By Sarah Lyall The author Cat Bohannon was a preteen in Atlanta in the 1980s when she saw the film “2001: A Space Odyssey” for the first time. As she took in its famous opening scene, in which a bunch of apes picks up a bunch of bones and quickly begins using them to hit each other, Bohannon was struck by the sheer maleness of the moment. “I thought, ‘Where are the females in this story?’” Bohannon said recently, imagining what those absent females might have been up to at that particular time. “It’s like, ‘Oh, sorry, I see you’re doing something really important with a rock. I’m just going to go over there behind that hill and quietly build the future of the species in my womb.” That realization was just one of what Bohannon, 44, calls “a constellation of moments” that led her to write her new book, “Eve: How the Female Body Drove 200 Million Years of Human Evolution.” A page-turning whistle-stop tour of mammalian development that begins in the Jurassic Era, “Eve” recasts the traditional story of evolutionary biology by placing women at its center. The idea is that by examining how women evolved differently from men, Bohannon argues, we can “provide the latest answers to women’s most basic questions about their bodies.” These include, she says: Why do women menstruate? Why do they live longer? And what is the point of menopause? These are timely questions. Thanks to regulations established in the 1970s, clinical trials in the United States have typically used mostly male subjects, from mice to humans. (This is known as “the male norm.”) Though that changed somewhat in 1994, when the National Institutes of Health updated its rules, even the new protocols are replete with loopholes. For example: “From 1996 to 2006, more than 79 percent of animal studies published in the scientific journal Pain included only male subjects,” she writes. © 2023 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 28907 - Posted: 09.13.2023

By Ann Gibbons Go to the Democratic Republic of the Congo, and you’re unlikely to encounter chimps so plump they have trouble climbing trees or vervet monkeys so chubby they huff and puff as they swing from branch to branch. Humans are a different story. Walk down a typical U.S. street and almost half of the people you encounter are likely to have obesity. Scientists have long blamed our status as the “fattest primate” on genes that help us store fat more efficiently or diets overloaded with sugars or fat. But a new study of 40 species of nonhuman primates, ranging from tiny mouse lemurs to hulking gorillas, finds many pack on the pounds just as easily as we do, regardless of diet, habitat, or genetic differences. All they need is extra food. “Lots of primates put on too much weight, the same as humans,” says Herman Pontzer, a biological anthropologist at Duke University and author of the new study, published this week in the Philosophical Transactions of the Royal Society B. “Humans are not special.” Some researchers have suggested our species is prone to obesity because our ancestors evolved to be incredibly efficient at storing calories. The adaptation would have helped our ancient relatives, who often faced famine after the transition to agriculture, get through lean times. This selection pressure for so-called thrifty genes set us apart from other primates, the thinking goes. But other primates can get fat. Kanzi, the first ape to show he understands spoken English, was triple the average weight of his bonobo species after years of being rewarded with bananas, peanuts, and other treats during research; scientists eventually put him on a diet. And then there was Uncle Fatty, an obese macaque who lived on the streets of Bangkok where tourists fed him milkshakes, noodles, and other junk food. He weighed an astonishing 15 kilograms—three times more than the average macaque—before he went to the monkey equivalent of a fat farm. © 2023 American Association for the Advancement of Science.

Keyword: Obesity; Evolution
Link ID: 28902 - Posted: 09.10.2023

By Carolyn Wilke Young jumping spiders dangle by a thread through the night, in a box, in a lab. Every so often, their legs curl and their spinnerets twitch — and the retinas of their eyes, visible through their translucent exoskeletons, shift back and forth. “What these spiders are doing seems to be resembling — very closely — REM sleep,” says Daniela Rößler, a behavioral ecologist at the University of Konstanz in Germany. During REM (which stands for rapid eye movement), a sleeping animal’s eyes dart about unpredictably, among other features. In people, REM is when most dreaming happens, particularly the most vivid dreams. Which leads to an intriguing question. If spiders have REM sleep, might dreams also unfold in their poppy-seed-size brains? Rößler and her colleagues reported on the retina-swiveling spiders in 2022. Training cameras on 34 spiders, they found that the creatures had brief REM-like spells about every 17 minutes. The eye-darting behavior was specific to these bouts: It didn’t happen at times in the night when the jumping spiders stirred, stretched, readjusted their silk lines or cleaned themselves with a brush of a leg. Though the spiders are motionless in the run-up to these REM-like bouts, the team hasn’t yet proved that they are sleeping. But if it turns out that they are — and if what looks like REM really is REM — dreaming is a distinct possibility, Rößler says. She finds it easy to imagine that jumping spiders, as highly visual animals, might benefit from dreams as a way to process information they took in during the day. Young jumping spiders have translucent skin. Behind their eyes, tube-shaped retinas move as the spiderlings look about. As shown in this sped-up video, researchers have also observed such retinal tube-shifting behavior in resting — possibly sleeping — spiders. In these intermittent, active bouts, the animals’ legs curl and their spinnerets twitch — suggesting that spiders may experience something like REM sleep. © 2023 Annual Reviews

Keyword: Sleep; Evolution
Link ID: 28896 - Posted: 09.07.2023

By Jori Lewis The squat abandoned concrete structure may have been a water tower when this tract of land in the grasslands of Mozambique was a cotton factory. Now it served an entirely different purpose: Housing a bat colony. To climb through the building’s low opening, bat researcher Césaria Huó and I had to battle a swarm of biting tsetse flies and clear away a layer of leaves and vines. My eyes quickly adjusted to the low light, but my nose, even behind a mask, couldn’t adjust to the smell of hundreds of bats and layers of bat guano—a fetid reek of urea with fishy, spicy overtones. But Huó had a different reaction. “I don’t mind the smell now,” she said. After several months of monitoring bat colonies in the Gorongosa National Park area as a master’s student in the park’s conservation biology program, Huó said she almost likes it. “Now, when I smell it, I know there are bats here.” Since we arrived at the tower during the daylight hours, I had expected the nocturnal mammals to be asleep. Instead, they were shaking their wings, flying from one wall or spot on the ceiling to another, swooping sometimes a bit too close to me for my comfort. But the bats didn’t care about me; they were cruising for mates. It was mating season, and we had lucked out to see their mating performances. Huó pointed out that some females were inspecting the males, checking out their wing flapping prowess. But Huó and her adviser, the polymath entomologist Piotr Naskrecki, did not bring me to this colony to view the bats’ seductive dances and their feats of flight, since those behaviors are already known to scientists. We were here to decipher what the bats were saying while doing them. Huó and Naskrecki had set up cameras and audio recorders the night before to learn more about these bats and try to understand the nature of the calls they use, listening for signs of meaning. © 2023 NautilusNext Inc., All rights reserved.

Keyword: Animal Communication; Evolution
Link ID: 28895 - Posted: 09.07.2023

By David Grimm Apart from Garfield’s legendary love of lasagna, perhaps no food is more associated with cats than tuna. The dish is a staple of everything from The New Yorker cartoons to Meow Mix jingles—and more than 6% of all wild-caught fish goes into cat food. Yet tuna (or any seafood for that matter) is an odd favorite for an animal that evolved in the desert. Now, researchers say they have found a biological explanation for this curious craving. In a study published this month in Chemical Senses, scientists report that cat taste buds contain the receptors needed to detect umami—the savory, deep flavor of various meats, and one of the five basic tastes in addition to sweet, sour, salty, and bitter. Indeed, umami appears to be the primary flavor cats seek out. That’s no surprise for an obligate carnivore. But the team also found these cat receptors are uniquely tuned to molecules found at high concentrations in tuna, revealing why our feline friends seem to prefer this delicacy over all others. “This is an important study that will help us better understand the preferences of our familiar pets,” says Yasuka Toda, a molecular biologist at Meiji University and a leader in studying the evolution of umami taste in mammals and birds. The work could help pet food companies develop healthier diets and more palatable medications for cats, says Toda, who was not involved with the industry-funded study. Cats have a unique palate. They can’t taste sugar because they lack a key protein for sensing it. That’s probably because there’s no sugar in meat, says Scott McGrane, a flavor scientist and research manager for the sensory science team at the Waltham Petcare Science Institute, which is owned by pet food–maker Mars Petcare UK. There’s a saying in evolution, he says: “If you don’t use it, you lose it.” Cats also have fewer bitter taste receptors than humans do—a common trait in uber-carnivores. But cats must taste something, McGrane reasoned, and that something is likely the savory flavor of meat. In humans and many other animals, two genes—Tas1r1 and Tas1r3—encode proteins that join together in taste buds to form a receptor that detects umami. Previous work had shown that cats express the Tas1r3 gene in their taste buds, but it was unclear whether they had the other critical puzzle piece.

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 28885 - Posted: 08.26.2023

Jon Hamilton Scientists have genetically engineered a squid that is almost as transparent as the water it's in. The squid will allow researchers to watch brain activity and biological processes in a living animal. Sponsor Message ARI SHAPIRO, HOST: For most of us, it would take magic to become invisible, but for some lucky, tiny squid, all it took was a little genetic tweaking. As part of our Weekly Dose of Wonder series, NPR's Jon Hamilton explains how scientists created a see-through squid. JON HAMILTON, BYLINE: The squid come from the Marine Biological Laboratory in Woods Hole, Mass. Josh Rosenthal is a senior scientist there. He says even the animal's caretakers can't keep track of them. JOSH ROSENTHAL: They're really hard to spot. We know we put it in this aquarium, but they might look for a half-hour before they can actually see it. They're that transparent. HAMILTON: Almost invisible. Carrie Albertin, a fellow at the lab, says studying these creatures has been transformative. CARRIE ALBERTIN: They are so strikingly see-through. It changes the way you interpret what's going on in this animal, being able to see completely through the body. HAMILTON: Scientists can watch the squid's three hearts beating in synchrony or see its brain cells at work. And it's all thanks to a gene-editing technology called CRISPR. A few years ago, Rosenthal and Albertin decided they could use CRISPR to create a special octopus or squid for research. ROSENTHAL: Carrie and I are highly biased. We both love cephalopods - right? - and we have for our entire careers. HAMILTON: So they focused on the hummingbird bobtail squid. It's smaller than a thumb and shaped like a dumpling. Like other cephalopods, it has a relatively large and sophisticated brain. Rosenthal takes me to an aquarium to show me what the squid looks like before its genes are altered. ROSENTHAL: Here is our hummingbird bobtail squid. You can see him right there in the bottom, just kind of sitting there hunkered down in the sand. At night, it'll come out and hunt and be much more mobile. © 2023 npr

Keyword: Brain imaging; Evolution
Link ID: 28883 - Posted: 08.26.2023