Chapter 6. Evolution of the Brain and Behavior

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By Elise Cutts In March 2019, on a train headed southwest from Munich, the neuroscientist Maximilian Bothe adjusted his careful grip on the cooler in his lap. It didn’t contain his lunch. Inside was tissue from half a dozen rattlesnake spinal cords packed in ice — a special delivery for his new research adviser Boris Chagnaud, a behavioral neuroscientist based on the other side of the Alps. In his lab at the University of Graz in Austria, Chagnaud maintains a menagerie of aquatic animals that move in unusual ways — from piranhas and catfish that drum air bladders to produce sound to mudskippers that hop around on land on two fins. Chagnaud studies and compares these creatures’ neuronal circuits to understand how new ways of moving might evolve, and Bothe was bringing his rattlesnake spines to join the endeavor. The ways that animals move are just about as myriad as the animal kingdom itself. They walk, run, swim, crawl, fly and slither — and within each of those categories lies a tremendous number of subtly different movement types. A seagull and a hummingbird both have wings, but otherwise their flight techniques and abilities are poles apart. Orcas and piranhas both have tails, but they accomplish very different types of swimming. Even a human walking or running is moving their body in fundamentally different ways. The tempo and type of movements a given animal can perform are set by biological hardware: nerves, muscle and bone whose functions are bound by neurological constraints. For example, vertebrates’ walking tempos are set by circuits in their spines that fire without any conscious input from the brain. The pace of that movement is dictated by the properties of the neuronal circuits that control them. For an animal to evolve a novel way of moving, something in its neurological circuitry has to change. Chagnaud wants to describe exactly how that happens. “In evolution, you don’t just invent the wheel. You take pieces that were already there, and you modify them,” he said. “How do you modify those components that are shared across many different species to make new behaviors?” © 2024 Simons Foundation.

Keyword: Evolution
Link ID: 29194 - Posted: 03.16.2024

By Erin Garcia de Jesús A genetic parasite may have robbed humans and other apes of their tails. Around 25 million years ago, this parasite, a small stretch of repetitive DNA called an Alu element, ended up in a gene important for tail development, researchers report in the Feb. 29 Nature. The single insertion altered the gene Tbxt in a way that seems to have sparked one of the defining differences between monkeys and apes: Monkeys have tails, apes don’t. “It was like lightning struck once,” says Jef Boeke, a geneticist at New York University Langone Health, and ape behinds ultimately became bare. The genetic tweak may also give insight into why some babies are born with spinal cord defects such as spina bifida, when the tube that holds the cord doesn’t close all the way (SN: 12/6/16). Alu elements are part of a group of genetic parasites known as transposons or jumping genes that can hop across genetic instruction books, inserting themselves into their hosts’ DNA (SN: 5/16/17). Sometimes, when the gene slips itself into a piece of DNA that is passed down to offspring, these insertions become permanent parts of our genetic code. Transposons, including more than 1 million Alu elements, are found throughout our genome, says geneticist and systems biologist Bo Xia of the Broad Institute in Cambridge, Mass. Researchers once thought of transposons as genetic garbage, but some have central roles in evolution. Without transposons, the placenta, immune system and insulation around nerve fibers may not exist (SN: 2/16/24). And humans might still have tails. To find out how apes lost their tails, Xia, then at NYU Langone Health, Boeke and colleagues analyzed 140 genes involved in vertebrate tail development. © Society for Science & the Public 2000–2024.

Keyword: Evolution; Epigenetics
Link ID: 29170 - Posted: 02.29.2024

By Anthony Ham What is the meaning of a cat’s meow that grows louder and louder? Or your pet’s sudden flip from softly purring as you stroke its back to biting your hand? It turns out these misunderstood moments with your cat may be more common than not. A new study by French researchers, published last month in the journal Applied Animal Behaviour Science, found that people were significantly worse at reading the cues of an unhappy cat (nearly one third got it wrong) than those of a contented cat (closer to 10 percent). The study also suggested that a cat’s meows and other vocalizations are greatly misinterpreted and that people should consider both vocal and visual cues to try to determine what’s going on with their pets. The researchers drew these findings from the answers of 630 online participants; respondents were volunteers recruited through advertisements on social media. Each watched 24 videos of differing cat behaviors. One third depicted only vocal communication, another third just visual cues, and the remainder involved both. “Some studies have focused on how humans understand cat vocalizations,” said Charlotte de Mouzon, lead author of the study and a cat behavior expert at the Université Paris Nanterre. “Other studies studied how people understand cats’ visual cues. But studying both has never before been studied in human-cat communication.” Cats display a wide range of visual signals: tails swishing side to side, or raised high in the air; rubbing and curling around our legs; crouching; flattening ears or widening eyes. Their vocals can range from seductive to threatening: meowing, purring, growling, hissing and caterwauling. At last count, kittens were known to use nine different forms of vocalization, while adult cats uttered 16. That we could better understand what a cat wants by using visual and vocal cues may seem obvious. But we know far less than we think we do. © 2024 The New York Times Compan

Keyword: Animal Communication; Evolution
Link ID: 29169 - Posted: 02.29.2024

By Annie Melchor When the first known flying dinosaurs took to the skies some 150 million years ago, the evolutionary leap relied on adaptations to their nervous system. The changes remained a mystery, though, because of the paucity of fossilized neural tissue. Now fresh clues have emerged from a study that started with the long-gone dinosaurs’ living kin: the common pigeon, Columba livia. Flight taps neural pathways involving the pigeon’s cerebellum, the new works shows, which prompted study investigator Amy Balanoff and her team to look specifically at that structure in digital brain “endocasts,” created by CT scanning fossilized dinosaur skulls. “The birds can help us look for certain things within these extinct animals,” says Balanoff, assistant professor of evolutionary biology at Johns Hopkins University. “Then these extinct animals can tell us about the evolutionary history leading up to living birds.” An analysis of the endocasts — from 10 dinosaur specimens dating to between 90 and 150 million years ago — revealed that the volume of the cerebellum expanded in birds’ closest relatives, but not in more distant ones. And at some point, the cerebellum began folding — instead of growing — to accommodate more neurons within a fixed cranial space, Balanoff says. The results suggest that the cerebellum was “flight-ready before flying,” says Crístian Gutiérrez-Ibáñez, an evolutionary biology research associate at the University of Alberta who was not involved in the study. “So the question is, why did dinosaurs get such a big cerebellum?” © 2024 Simons Foundation

Keyword: Evolution; Movement Disorders
Link ID: 29162 - Posted: 02.25.2024

By Christine Dell'Amore Thunderclouds rolled across Kenya’s Masai Mara savanna as the spotted hyena cubs played, tumbling over each other in the wet grass. The cubs’ mother lounged nearby, rising occasionally to discourage a bigger one-year-old from joining the little play group. When the older animal approached again, one of the pluckier cubs took a cue from its high-ranking mom and stood tall, trying its best to look intimidating. That action seemed comical, but both animals knew their place. The larger, lower ranking hyena stopped short, then bowed its head and slunk off. Photographer Jen Guyton recorded this scene with an infrared camera, allowing an intimate look into hyenas’ nocturnal behaviors. In doing so, she provided a small window into the intriguing structure of hyena society, where all members inherit their place in the pecking order from their mother. Females are in charge, and rank means everything—a matrilineal system that has fueled the spotted hyena’s rise as the most abundant large carnivore in Africa. These and other insights into hyena behavior wouldn’t be possible were it not for 35 years of on-the-ground research by Kay Holekamp, founder of the Mara Hyena Project. Her efforts have helped reveal a creature noted for its advanced society, cognition, and ability to adjust to new surroundings. Holekamp, a biologist at Michigan State University, has been studying the African species in the Masai Mara since 1988—one of the longest running investigations of any mammal ever. “I thought I’d be there for two years,” she says, “but I got hooked.” Hooked on hyenas? Mention their name, and most people grimace. Aristotle described them as “exceedingly fond of putrefied flesh.” Theodore Roosevelt called them a “singular mixture of abject cowardice and the utmost ferocity.” Across Africa, hyenas are seen as evil, greedy, and associated with witchcraft and sexual deviance. Even the 1994 movie The Lion King portrayed them as cunning and malicious. © 1996-2015 National Geographic Society

Keyword: Sexual Behavior; Evolution
Link ID: 29149 - Posted: 02.13.2024

By Shruti Ravindran When preparing to become a butterfly, the Eastern Black Swallowtail caterpillar wraps its bright striped body within a leaf. This leaf is its sanctuary, where it will weave its chrysalis. So when the leaf is disturbed by a would-be predator—a bird or insect—the caterpillar stirs into motion, briefly darting out a pair of fleshy, smelly horns. To humans, these horns might appear yellow—a color known to attract birds and many insects—but from a predator’s-eye-view, they appear a livid, almost neon violet, a color of warning and poison for some birds and insects. “It’s like a jump scare,” says Daniel Hanley, an assistant professor of biology at George Mason University. “Startle them enough, and all you need is a second to get away.” Hanley is part of a team that has developed a new technique to depict on video how the natural world looks to non-human species. The method is meant to capture how animals use color in unique—and often fleeting—behaviors like the caterpillar’s anti-predator display. Most animals, birds, and insects possess their own ways of seeing, shaped by the light receptors in their eyes. Human retinas, for example, are sensitive to three wavelengths of light—blue, green, and red—which enables us to see approximately 1 million different hues in our environment. By contrast, many mammals, including dogs, cats, and cows, sense only two wavelengths. But birds, fish, amphibians, and some insects and reptiles typically can sense four—including ultraviolet light. Their worlds are drenched in a kaleidoscope of color—they can often see 100 times as many shades as humans do. Hanley’s team, which includes not just biologists but multiple mathematicians, a physicist, an engineer, and a filmmaker, claims that their method can translate the colors and gradations of light perceived by hundreds of animals to a range of frequencies that human eyes can comprehend with an accuracy of roughly 90 percent. That is, they can simulate the way a scene in a natural environment might look to a particular species of animal, what shifting shapes and objects might stand out most. The team uses commercially available cameras to record video in four color channels—blue, green, red, and ultraviolet—and then applies open source software to translate the picture according to the mix of light receptor sensitivities a given animal may have. © 2024 NautilusNext Inc.,

Keyword: Vision; Evolution
Link ID: 29133 - Posted: 02.06.2024

By Erin Garcia de Jesús Bruce the kea is missing his upper beak, giving the olive green parrot a look of perpetual surprise. But scientists are the astonished ones. The typical kea (Nestor notabilis) sports a long, sharp beak, perfect for digging insects out of rotten logs or ripping roots from the ground in New Zealand’s alpine forests. Bruce has been missing the upper part of his beak since at least 2012, when he was rescued as a fledgling and sent to live at the Willowbank Wildlife Reserve in Christchurch. The defect prevents Bruce from foraging on his own. Keeping his feathers clean should also be an impossible task. In 2021, when comparative psychologist Amalia Bastos arrived at the reserve with colleagues to study keas, the zookeepers reported something odd: Bruce had seemingly figured out how to use small stones to preen. “We were like, ‘Well that’s weird,’ ” says Bastos, of Johns Hopkins University. Over nine days, the team kept a close eye on Bruce, quickly taking videos if he started cleaning his feathers. Bruce, it turned out, had indeed invented his own work-around to preen, the researchers reported in 2021 in Scientific Reports. First, Bruce selects the proper tool, rolling pebbles around in his mouth with his tongue and spitting out candidates until he finds one that he likes, usually something pointy. Next, he holds the pebble between his tongue and lower beak. Then, he picks through his feathers. “It’s crazy because the behavior was not there from the wild,” Bastos says. When Bruce arrived at Willowbank, he was too young to have learned how to preen. And no other bird in the aviary uses pebbles in this way. “It seems like he just innovated this tool use for himself,” she says. © Society for Science & the Public 2000–2024.

Keyword: Intelligence; Evolution
Link ID: 29117 - Posted: 01.27.2024

By Kenna Hughes-Castleberry Crows, ravens and other birds in the Corvidae family have a head for numbers. Not only can they make quantity estimations (as can many other animal species), but they can learn to associate number values with abstract symbols, such as “3.” The biological basis of this latter talent stems from specific number-associated neurons in a brain region called the nidopallium caudolaterale (NCL), a new study shows. The region also supports long-term memory, goal-oriented thinking and number processing. Discovery of the specialized neurons in the NCL “helps us understand the origins of our counting and math capabilities,” says study investigator Andreas Nieder, professor of animal physiology at the University of Tübingen. Until now, number-associated neurons — cells that fire especially frequently in response to an animal seeing a specific number — had been found only in the prefrontal cortex of primates, which shared a common ancestor with corvids some 300 million years ago. The new findings imply that the ability to form number-sign associations evolved independently and convergently in the two lineages. “Studying whether animals have similar concepts or represent numerosity in ways that are similar to what humans do helps us establish when in our evolutionary history these abilities may have emerged and whether these abilities emerge only in species with particular ecologies or social structures,” says Jennifer Vonk, professor of psychology at Oakland University, who was not involved in the new study. Corvids are considered especially intelligent birds, with previous studies showing that they can create and use tools, and may even experience self-recognition. Nieder has studied corvids’ and other animals’ “number sense,” or the ability to understand numerical values, for more than a decade. His previous work revealed specialized neurons in the NCL that recognize and respond to different quantities of items — including the number zero. But he tested the neurons only with simple pictures and signs that have inherent meaning for the crows, such as size. © 2023 Simons Foundation.

Keyword: Intelligence; Evolution
Link ID: 29111 - Posted: 01.23.2024

Nicola Davis Science correspondent Breaking up is hard to do, but it seems the brain may have a mechanism to help get over an ex. Researchers studying prairie voles say the rodents, which form monogamous relationships, experience a burst of the pleasure hormone dopamine in their brain when seeking and reuniting with their partner. However, after being separated for a lengthy period, they no longer experience such a surge. “We tend to think of it as ‘getting over a breakup’ because these voles can actually form a new bond after this change in dopamine dynamics – something they can’t do while the bond is still intact,” said Dr Zoe Donaldson, a behavioural neuroscientist at CU Boulder and senior author of the work. Writing in the journal Current Biology, the team describe how they carried out a series of experiments in which voles had to press levers to access either their mate or an unknown vole located on the other side of a see-through door. The team found the voles had a greater release of dopamine in their brain when pressing levers and opening doors to meet their mate than when meeting the novel vole. They also huddled more with their mate on meeting, and experienced a greater rise in dopamine while doing so. Donaldson said: “We think the difference is tied to knowing you are about to reunite with a partner and reflects that it is more rewarding to reunite with a partner than go hang out with a vole they don’t know.” However, these differences in dopamine levels were no longer present after they separated pairs of voles for four weeks – a considerable period in the lifetime of the rodents. Differences in huddling behaviour also decreased. The researchers say the findings suggest a devaluation of the bond between pairs of voles, rather than that they have forgotten each other. © 2024 Guardian News & Media Limited

Keyword: Sexual Behavior; Evolution
Link ID: 29104 - Posted: 01.18.2024

By Jude Coleman When it comes to tail wagging among dogs, some questions still hound researchers. We know that domesticated dogs (Canis familiaris) use their tails to communicate — with other dogs as well as humans — and even what various types of wags mean, researchers note in a new review of the scientific literature. But we don’t know why dogs seem to wag more than other canines or even how much of it is under their control, ethologist Silvia Leonetti and colleagues report January 17 in Biology Letters. “Among all possible animal behavior that humans experience in everyday life, domestic dog tail wagging is one of the most common,” says Leonetti, who is now at the University of Turin in Italy. “But a lot of dog behavior remains a scientific enigma.” So Leonetti and her colleagues pored through previous studies to figure out what elements of tail wagging are understood and which remain mysterious. They also hypothesized about the behavior’s origins: Perhaps tail wagging placates some human need for rhythm, the researchers suggest, or maybe the behavior is a genetic tagalong, a trait tied to others that humans bred into domesticated dogs. “People think wagging tail equals happy dog. But it’s actually a lot more complicated than that,” says Emily Bray, an expert in canine cognition at the University of Arizona in Tucson who was not involved with the work. Understanding why dogs wag their tails is important partly from an animal welfare perspective, she says, as it could help dog owners read their pups’ cues better. One main thing that researchers know about tail wagging is that it’s used predominantly for communication instead of locomotion, like a whale, or swatting away bugs, like a horse. Wagging also means different things depending on how the tail is wagged, such as its height or side-to-side movement. © Society for Science & the Public 2000–2024.

Keyword: Animal Communication; Emotions
Link ID: 29103 - Posted: 01.18.2024

Diana Fleischman Because of the flaming culture wars, feminists and others who disagree about the nature of sex or sex differences often ascribe significant harms to researchers who claim that sex is binary or who acknowledge biological sex differences. These perceived harms include oppression, inequality, and even murder and suicide. As a result, many influential voices in the sex difference debate rarely engage in dialogue. This context made “The Big Conversation”—an October conference that brought together a diverse group of feminists, evolutionary psychologists, biologists, and neuroscientists—such a remarkable event. The rarity of such a meeting was highlighted by the cancellation of a panel on sex differences at an annual anthropological conference just a few days before. People who had sniped at each other for years through academic papers and social media not only shared stages and panels, they broke bread together. Attendees on all sides of the issue held my baby, whom I brought along. The fear of meeting ideological opponents often leads to the expectation of hostility in person, but what’s worse is that you often will come to like them! The Big Conversation took years to come together. It was organized by sex difference expert Marco Del Giudice and Paul Golding of the Santa Fe Boys Foundation. This foundation is dedicated to exploring how to help boys and young men and was the event’s sponsor. The conference featured 16 talks and 5 discussion sections. The entire conference is available for viewing (for free!) on the Santa Fe Boys Foundation website. A central questions in sex difference research concerns the origins of differences between men and women. Are these differences primarily the result of socialization, culture, and stereotype effects, or are these differences largely innate or biological? We can call these perspectives, as Carole Hooven did during her talk, the strong socialization view and the strong biology view, respectively. Many of the conference attendees, like Gina Rippon, Cordelia Fine and Daphna Joel, endorse the strong socialization view of sex differences, arguing that men and women are innately psychologically similar but are driven into different roles by cultural forces and socialization. This perspective sparks controversy surrounding discussions on biological sex differences because its proponents argue that legitimizing and publicizing sex differences creates them where they did not exist before. © 2024 Colin Wright

Keyword: Sexual Behavior; Evolution
Link ID: 29095 - Posted: 01.13.2024

By Carl Zimmer Multiple sclerosis, an autoimmune disease that affects 2.9 million people, presents a biological puzzle. Many researchers suspect that the disease is triggered by a virus, known as Epstein-Barr, which causes the immune system to attack the nerves and can leave patients struggling to walk or talk. But the virus can’t be the whole story, since nearly everyone is infected with it at some point in life. A new study found a possible solution to this paradox in the skeletal remains of a lost tribe of nomads who herded cattle across the steppes of western Asia 5,000 years ago. It turns out that the nomads carried genetic mutations that most likely protected them from pathogens carried by their animals, but that also made their immune systems more sensitive. These genes, the study suggests, made the nomads’ descendants prone to a runaway immune response. The finding is part of a larger, unprecedented effort to understand how the evolutionary past has shaped the health of living people. Researchers are analyzing thousands of genomes of people who lived between Portugal and Siberia and between Norway and Iran roughly 3,000 to 11,000 years ago. They hope to trace the genetic roots of not only multiple sclerosis, but also diabetes, schizophrenia and many other modern illnesses. “We are taking ancient human genomics to a whole new level,” said Eske Willerslev, a geneticist at the University of Copenhagen who led the effort. The researchers published the multiple sclerosis study as well as three other papers on the genetics and health of ancient peoples on Wednesday in the journal Nature. For more than a decade, Dr. Willerslev and other researchers have been pulling DNA from ancient human bones. By comparing the surviving genetic material with that of living people, the scientists have been able to track some of the most significant migrations of people across the world. © 2024 The New York Times Company

Keyword: Multiple Sclerosis; Evolution
Link ID: 29093 - Posted: 01.11.2024

By Cara Giovanetti The human brain's billions of neurons represent a menagerie of cells that are among both the most highly specialized and variable ones in our bodies. Neurons convert electrical signals to chemical signals, and in humans, their lengths can be so tiny as to span just the tip of a sharpened pencil or, in some cases, even stretch the width of a doorway. Their flexible control of movement and decision-making explains why they are so key to survival in the animal kingdom. Most animals depend on their allotment of neurons for survival. It might stand to reason, then, that the common ancestor of all of these animals also moved about the Earth millions of years ago under the guidance of electrochemical signals transmitted and received by networks of neurons. The idea that these pivotal cells evolved multiple times seems implausible because neurons are highly complex cells, and they are also quite similar among animal lineages. But a series of recent evolutionary biology studies are straining the assumption that all animal neurons have a single origin. These findings are the culmination of several years’ worth of research on and debate about early evolutionary animal lineages and the cells and systems present in those species. The first such finding came from studying relationships among early animals, with a focus on two particular types of organisms: sponges (including sea sponges and freshwater varieties) and ctenophores, invertebrates often known as comb jellies, though they are unrelated to jellyfish. For roughly 15 years, evolutionary biologists have been divided over whether ctenophores or sponges were the first animals to branch from all other animals in the evolutionary tree. Hundreds of millions of years ago the common ancestor to all living animals branched into two species. On one side was the common ancestor of all groups of animals except for one. On the other side was that “one”—the “sister group” that was the first to diverge from all other animals. A persistent question has been whether the sister group was the sponges or ctenophores. A compelling paper published last year lends strong support to the hypothesis that ctenophores are, in fact, the long-sought sister group. Ctenophores, the researchers found, branched off before sponges and are therefore the group most distantly related to all other animals. Yet despite the new evidence, what exactly happened in evolutionary history is still unsettled because of the puzzle it poses in explaining the evolution of neurons. © 2023 SCIENTIFIC AMERICAN,

Keyword: Evolution
Link ID: 29081 - Posted: 01.06.2024

Kamal Nahas Peter Hegemann, a biophysicist at Humboldt University, has spent his career exploring interactions between proteins and light. Specifically, he studies how photoreceptors detect and respond to light, focusing largely on rhodopsins, a family of membrane photoreceptors in animals, plants, fungi, protists, and prokaryotes.1 Early in his career, his curiosity led him to an unknown rhodopsin in green algae that later proved to have useful applications in neuroscience research. Hegemann became a pioneer in the field of optogenetics, which revolutionized the ways in which scientists draw causal links between neuronal activity and behavior. In the early 1980s during his graduate studies at the Max Planck Institute of Biochemistry, Hegemann spent his days exploring rhodopsins in bacteria and archaea. However, the field was crowded, and he was eager to study a rhodopsin that scientists knew nothing about. Around this time, Kenneth Foster, a biophysicist at Syracuse University, was investigating whether the green algae Chlamydomonas, a photosynthetic unicellular eukaryote related to plants, used a rhodopsin in its eyespot organelle to detect light and trigger the algae to swim. He struggled to pinpoint the protein itself, so he took a roundabout approach and started interfering with nearby molecules that interact with rhodopsins.2 Rhodopsins require the small molecule retinal to function as a photoreceptor. When Foster depleted Chlamydomonas of its own retinal, the algae were unable to use light to direct movement, a behavior that was restored when he introduced retinal analogues. In 1985, Hegemann joined Foster’s group as a postdoctoral researcher to continue this work. “I wanted to find something new,” Hegemann said. “Therefore, I worked on an exotic organism and an exotic topic.” A year later, Hegemann started his own research group at the Max Planck Institute of Biochemistry where he searched for the green algae’s rhodopsin that Foster proposed should exist. © 1986–2024 The Scientist.

Keyword: Brain imaging; Vision
Link ID: 29077 - Posted: 01.03.2024

By Elise Cutts On a summer night in the Bay of Naples, hordes of worms swam upward from the seagrass toward the water’s surface under the light of a waning moon. Not long before, the creatures began a gruesome sexual metamorphosis: Their digestive systems withered, and their swimming muscles grew, while their bodies filled with eggs or sperm. The finger-length creatures, now little more than muscular bags of sex cells, fluttered to the surface in unison and, over a few hours, circled each other in a frantic nuptial dance. They released countless eggs and sperm into the bay — and then the moonlit waltz ended in the worms’ deaths. The marine bristle worm Platynereis dumerilii gets only one chance to mate, so its final dance had better not be a solo. To ensure that many worms congregate at the same time, the species synchronizes its reproductive timing with the cycles of the moon. How can an undersea worm tell when the moon is at its brightest? Evolution’s answer is a precise celestial clock wound by a molecule that can sense moonbeams and sync the worms’ reproductive lives to lunar phases. No one had ever seen how one of these moonlight molecules worked. Recently, however, in a study published in Nature Communications, researchers in Germany determined the different structures that one such protein in bristle worms takes in darkness and in sunlight. They also uncovered biochemical details that help explain how the protein distinguishes between brighter sunbeams and softer moonglow. It’s the first time that scientists have determined the molecular structure of any protein responsible for syncing a biological clock to the phases of the moon. “I’m not aware of another system that has been looked at with this degree of sophistication,” said the biochemist Brian Crane of Cornell University, who was not involved in the new study. © 2023 An editorially independent publication supported by the Simons Foundation.

Keyword: Biological Rhythms; Evolution
Link ID: 29062 - Posted: 12.22.2023

By Ann Gibbons Louise hadn’t seen her sister or nephew for 26 years. Yet the moment she spotted them on a computer screen, she recognized them, staring hard at their faces. The feat might have been impressive enough for a human, but Louise is a bonobo—one who had spent most of her life at a separate sanctuary from these relatives. The discovery, published today in the Proceedings of the National Academy of Sciences, reveals that our closest primate cousins can remember the faces of friends and family for years, and sometimes even decades. The study, experts say, shows that the capability for long-term social memory is not unique to people, as was long believed. “It’s a remarkable finding,” says Frans de Waal, a primatologist at Emory University who was not involved with the work. “I’m not even sure we humans remember most individuals we haven’t seen for 2 decades.” The research, he says, raises the possibility that other animals can also do this and may remember far more than we give them credit for. Trying to figure out whether nonhuman primates remember a face isn’t simple. You can’t just ask them. So in the new study, comparative psychologist Christopher Krupenye at Johns Hopkins University and colleagues used eye trackers, infrared cameras that noninvasively map a subject’s gaze as they look at images of people or objects. The scientists worked with 26 chimpanzees and bonobos living in three zoos or sanctuaries in Europe and Japan. The team showed the animals photos of the faces of two apes placed side by side on the screen at the same time for 3 seconds. Some images were of complete strangers; some were of close friends, foes, or family members who had once lived in their same social groups, but whom they hadn’t seen in years.

Keyword: Attention; Learning & Memory
Link ID: 29058 - Posted: 12.19.2023

By Carl Zimmer Neanderthals were morning people, a new study suggests. And some humans today who like getting up early might credit genes they inherited from their Neanderthal ancestors. The new study compared DNA in living humans with genetic material retrieved from Neanderthal fossils. It turns out that Neanderthals carried some of the same clock-related genetic variants as do people who report being early risers. Since the 1990s, studies of Neanderthal DNA have exposed our species’ intertwined history. About 700,000 years ago, our lineages split apart, most likely in Africa. While the ancestors of modern humans largely stayed in Africa, the Neanderthal lineage migrated into Eurasia. About 400,000 years ago, the population split in two. The hominins who spread west became Neanderthals. Their cousins to the east evolved into a group known as Denisovans. The two groups lived for hundreds of thousands of years, hunting game and gathering plants, before disappearing from the fossil record about 40,000 years ago. By then, modern humans had expanded out of Africa, sometimes interbreeding with Neanderthals and Denisovans. And today, fragments of their DNA can be found in most living humans. Research carried out over the past few years by John Capra, a geneticist at the University of California, San Francisco, and other scientists suggested that some of those genes passed on a survival advantage. Immune genes inherited from Neanderthals and Denisovans, for example, might have protected them from new pathogens they had not encountered in Africa. Dr. Capra and his colleagues were intrigued to find that some of the genes from Neanderthals and Denisovans that became more common over generations were related to sleep. For their new study, published in the journal Genome Biology and Evolution, they investigated how these genes might have influenced the daily rhythms of the extinct hominins. © 2023 The New York Times Company

Keyword: Biological Rhythms; Evolution
Link ID: 29052 - Posted: 12.16.2023

By Joseph Howlett Garter snakes have something in common with elephants, orcas, and naked mole rats: They form social groups that center around females. The snakes have clear “communities” composed of individuals they prefer hanging out with, and females act as leaders that tie the groups together and guide their members’ movements, according to the most extensive field study of snake sociality ever carried out. “This is an important first step in understanding how a community of snakes is organized in the wild,” says Gordon Burghardt, an ecologist at the University of Tennessee, Knoxville, who was not involved in the research. Other experts agree: “This is a big deal,” says integrative biologist Robert Mason of Oregon State University. “It’s a whole new avenue of research that I don’t think people have really given any thought to.” Ecologists had long assumed snakes are antisocial loners that hang out together only for core functions such as mating and hibernation. However, in 2020, Morgan Skinner, a behavioral ecologist at Wilfrid Laurier University, and collaborators showed in laboratory experiments that captive garter snakes have “friends”—specific snakes whose company they prefer over others. Still, studies of wild snakes were lacking “because they’re so secretive and difficult to find,” Skinner says. Then he learned that the Ontario Ministry of Transportation had funded an unprecedented long-term study of a huge population of Butler’s garter snakes (Thamnophis butleri) in Windsor, Canada. Ecologists began to monitor the flute-size slitherers in 2009 to keep them safe from nearby road construction. They regularly captured snakes in the 250-hectare study area, using identifying markings to track more than 3000 individuals over a 12-year span—about the lifetime of a garter snake. “We were mainly monitoring the population after they were relocated, to make sure they were thriving,” says Megan Hazell, a biologist with the consulting firm WSP, who led the field research as a graduate student at Queen’s University.

Keyword: Evolution; Sexual Behavior
Link ID: 29050 - Posted: 12.16.2023

By Jake Buehler Nesting chinstrap penguins take nodding off to the extreme. The birds briefly dip into a slumber many thousands of times per day, sleeping for only seconds at a time. The penguins’ breeding colonies are noisy and stressful places, and threats from predatory birds and aggressive neighbor penguins are unrelenting. The extremely disjointed sleep schedule may help the penguins to protect their young while still getting enough shut-eye, researchers report in the Dec. 1 Science. The findings add to evidence “that avian sleep can be very different from the sleep of land mammals,” says UCLA neuroscientist Jerome Siegel. Nearly a decade ago, behavioral ecologist Won Young Lee of the Korea Polar Research Institute in Incheon noticed something peculiar about how chinstrap penguins (Pygoscelis antarcticus) nesting on Antarctica’s King George Island were sleeping. They would seemingly doze off for very short periods of time in their cacophonous colonies. Then in 2018, Lee learned about frigate birds’ ability to steal sleep while airborne on days-long flights. Lee teamed up with sleep ecophysiologist Paul-Antoine Libourel of the Lyon Neuroscience Research Center in France and other researchers to investigate the penguins’ sleep. In 2019, the team studied the daily sleep patterns of 14 nesting chinstrap penguins using data loggers mounted on the birds’ backs. The devices had electrodes surgically implanted into the penguins’ brains for measuring brain activity. Other instruments on the data loggers recorded the animals’ movements and location. Nesting penguins had incredibly fragmented sleep patterns, taking over 600 “microsleeps” an hour, each averaging only four seconds, the researchers found. At times, the penguins slept with only half of their brain; the other half stayed awake. All together, the oodles of snoozes added up, providing over 11 hours of sleep for each brain hemisphere across more than 10,000 brief sleeps each day. © Society for Science & the Public 2000–2023.

Keyword: Sleep; Evolution
Link ID: 29028 - Posted: 12.02.2023

By Annie Roth A few years ago, Nicolas Fasel, a biologist at the University of Lausanne in Switzerland, and his colleagues developed a fascination with the penises of serotine bats, a species found in woodlands and the attics of old buildings across Europe and Asia. Serotine bats sport abnormally long penises with wide, heart-shaped heads. When erect, the members are around seven times longer than the female’s vagina, and their bulbous heads are seven times wider than the female’s vaginal opening. “We wondered: How does that work? How can they use that for copulation?” Dr. Fasel recalled. What they discovered has overturned an assumption about mammalian reproduction, namely that procreation must always involve penetration. In a study, published Monday in the journal Current Biology, Dr. Fassel and his colleagues presented evidence that serotine bats mate without penetration, making them the first mammals known to do so. Instead of using their penises to penetrate their partners, the scientists found, the male bats use them to push their partner’s tail membrane out of the way so they can align their openings and engage in contact mating, a behavior similar to one found in birds and known as “cloacal kissing.” To learn how these bats overcome their substantial genital size difference, Dr. Fasel and his colleagues analyzed nearly 100 videos of serotine bats mating. The videos were provided by a bat rehabilitation center in Ukraine and a citizen scientist filming bats in the attic of a church in the Netherlands. The footage revealed a mating strategy unlike any other used by mammals. While the two bats hang upside down, the male climbs on the female’s back and grasps the nape of her neck. Once he has a firm hold, the male will use his erect penis to push the female’s tail membrane to the side and probe between her legs until he has located her vulva. The male then presses the heart-shaped head of his penis to the female’s vulva and holds it there until the deed is done. While this process took less than an hour for most of the couples the researchers observed, one pair went at it for nearly 13 hours. “It’s a really weird reproductive strategy, but bats are weird and have a lot of weird reproductive strategies,” said Patty Brennan, a biologist at Mount Holyoke College in Massachusetts who studies the evolution of genital morphology but was not involved in the study. © 2023 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 29014 - Posted: 11.22.2023