Chapter 6. Evolution of the Brain and Behavior

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By Priyanka Runwal Everyone needs to cool off on a scorching summer day, even chimpanzees. Where do the primates go on sizzling days when woodlands and forests don’t provide respite from the heat? But not just any chimps. New research shows that on Senegal’s savannas, home to a population of chimpanzees that has long fascinated scientists for their distinct behaviors, you’re more likely to find mama chimps than adult males or non-lactating females hiding out in cool caves. Their visits coincided with the hottest times of day and became more frequent during the hottest months of the year, according to the study published last month in the International Journal of Primatology. They also made these visits despite the risks of encounters with predators, showing how important the locations are for helping them survive and bring up babies in a challenging landscape that is threatened by human activities. In southeastern Senegal, temperatures spike to 110 degrees Fahrenheit and fires burn large parts of the landscape over a seven-month dry season. Several natural cave formations pock the terrain, and they can be up to 55 degrees cooler than the surrounding grasslands. The region is also home to the northernmost population of western chimpanzees, a critically endangered subspecies that mostly lives in large swathes of open grasslands and woodlands in this area. In 2001, Jill Pruetz, a primatologist then at Iowa State University, gathered evidence of western chimpanzees using caves in the area, suspecting that they used them to escape the heat and possibly avoid heat stroke and other ill health effects of the dry season. But she reached few conclusions about whether all of the chimps used the caves as often as others. Kelly Boyer Ontl, a primatologist at Ball State University in Indiana and lead author of the new study, said, “I was really interested in finding out what chimpanzees are doing in caves, when are they using it and who’s going in there.” © 2020 The New York Times Company

Keyword: Evolution
Link ID: 27409 - Posted: 08.08.2020

By Helen Macdonald I found a dead common swift once, a husk of a bird under a bridge over the River Thames, where sunlight from the water cast bright scribbles on the arches above. I picked it up, held it in my palm, saw the dust in its feathers, its wings crossed like dull blades, its eyes tightly closed, and realized that I didn’t know what to do. This was a surprise. Encouraged by books, I’d always been the type of Gothic amateur naturalist who preserved interesting bits of the dead. I cleaned and polished fox skulls; disarticulated, dried and kept the wings of roadkill birds. But I knew, looking at the swift, that I could not do anything like that to it. The bird was suffused with a kind of seriousness very akin to holiness. I didn’t want to leave it there, so I took it home, swaddled it in a towel and tucked it in the freezer. It was in early May the next year, as soon as I saw the first returning swifts flowing down from the clouds, that I knew what I had to do. I went to the freezer, took out the swift and buried it in the garden one hand’s-width deep in earth newly warmed by the sun. Swifts are magical in the manner of all things that exist just a little beyond understanding. Once they were called the “Devil’s bird,” perhaps because those screaming flocks of black crosses around churches seemed pulled from darkness, not light. But to me, they are creatures of the upper air, and of their nature unintelligible, which makes them more akin to angels. Unlike all other birds I knew as a child, they never descended to the ground. When I was young, I was frustrated that there was no way for me to know them better. They were so fast that it was impossible to focus on their facial expressions or watch them preen through binoculars. They were only ever flickering silhouettes at 30, 40, 50 miles an hour, a shoal of birds, a pouring sheaf of identical black grains against bright clouds. There was no way to tell one bird from another, nor to watch them do anything other than move from place to place, although sometimes, if the swifts were flying low over rooftops, I’d see one open its mouth, and that was truly uncanny, because the gape was huge, turning the bird into something uncomfortably like a miniature basking shark. Even so, watching them with the naked eye was rewarding in how it revealed the dynamism of what before was merely blankness. Swifts weigh about 1½ ounces, and their surfing and tacking against the pressures of oncoming air make visible the movings of the atmosphere. © 2020 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 27391 - Posted: 07.29.2020

Masakazu (Mark) Konishi, the Bing Professor of Behavioral Biology, Emeritus, passed away on July 23. He was 87 years old. Renowned for his work on the neuroscience underlying the behavior of owls and songbirds, Konishi joined the Caltech faculty as a professor of biology in 1975, becoming the Bing Professor of Behavioral Biology in 1980. Since the early 1960s, Konishi was a leader in the field of avian neuroethology—the neurobiological study of natural behavior, such as prey capture by owls and singing in songbirds. In his laboratory at Caltech, Konishi advised dozens of graduate students and postdoctoral scholars. His team worked extensively on the auditory systems of barn owls, which use their acute hearing to home in on prey on the ground, even in total darkness. Konishi was the first to theorize that young birds initially remember a tutor song and use the memory as a template to guide the development of their own song. Konishi was born in Kyoto, Japan, on February 17, 1933. He attended Hokkaido University in Sapporo, Japan, for his bachelor and master of science degrees, after which he attended the UC Berkeley for his PhD. Under Berkeley professor Peter Marler, Konishi focused his doctoral research on the idea of central coordination. Konishi began a full professorship at Caltech in 1975. He was the Bing Professor of Behavioral Biology until his retirement in 2013. From 1977 to 1980, Konishi served as the division's executive officer for biology.

Keyword: Animal Communication; Language
Link ID: 27383 - Posted: 07.27.2020

Ewen Callaway Despite their rough and tumble existence, Neanderthals had a biological predisposition to a heightened sense of pain, finds a first-of-its kind genome study published in Current Biology on 23 July1. Evolutionary geneticists found that the ancient human relatives carried three mutations in a gene encoding the protein NaV1.7, which conveys painful sensations to the spinal cord and brain. They also showed that in a sample of British people, those who had inherited the Neanderthal version of NaV1.7 tend to experience more pain than others. “It’s a first example, to me, about how we begin to perhaps get an idea about Neanderthal physiology by using present-day people as transgenic models,” says Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who led the work with Hugo Zeberg at the Karolinska Institute in Stockholm. Pain-sensing protein Researchers have access to only a few Neanderthal genomes, and most of those have been sequenced at a low resolution. This has made it hard to identify mutations that evolved after their lineage split from that of humans some 500,000–750,000 years ago. But in the past few years, Pääbo and his team have generated three high-quality Neanderthal genomes from DNA found in caves in Croatia and Russia. This allows them to confidently identify mutations that were probably common in Neanderthals, yet very rare in humans. Mutations in a gene called SCN9A — which encodes the NaV1.7 protein — stood out because all of the Neanderthals had three mutations that alter the shape of the protein. The mutated version of the gene was found on both sets of chromosomes in all three Neanderthals, hinting that it was common across their populations. © 2020 Springer Nature Limited

Keyword: Pain & Touch; Evolution
Link ID: 27382 - Posted: 07.25.2020

By Cara Giaimo Even if you’re not a bird person, you probably know the jaunty song of the white-throated sparrow. It plays on loop in North America’s boreal forests, a classic as familiar as the chickadee’s trill and the mourning dove’s dirge. It even has its own mnemonic, “Old Sam Peabody-Peabody-Peabody.” But over the past half-century, the song’s hook — its triplet ending — has changed, replaced by a new, doublet-ended variant, according to a paper published Thursday in Current Biology. It seems the sparrows want to sing something new. The study, which took 20 years, is “the first to track the cultural evolution of birdsong at the continental scale,” said Mason Youngblood, a doctoral candidate in animal behavior at the CUNY Graduate Center who was not involved in the research. It describes a much broader and more rapid shift in birdsong than was previously thought to occur. Scott Ramsay, a behavioral ecologist at Wilfrid Laurier University in Ontario, was the first to notice that the forest sounded a little off during a visit to western Canada with Ken Otter, a professor at the University of Northern British Columbia. “He said, ‘Your birds are singing something weird,’” Dr. Otter recalled. Dr. Otter recorded some white-throated sparrow songs and turned them into spectrograms — visualizations that lay birdsongs out, so they can be more easily compared. The classic “Old Sam Peabody-Peabody-Peabody” songs ended in a triplet pattern: repeated sets of three notes. The new songs ended in doublets, like the record got stuck: “Old Sam Peabuh-Peabuh-Peabuh-Peabuh.” It was “a different kind of syncopation pattern,” Dr. Otter said. “They were kind of stuttering it.” Like many birds, male white-throated sparrows use songs to signal where their territory is, and to attract mates. Each individual sparrow has his own way of starting the song, but they all converge on a shared ending. © 2020 The New York Times Company

Keyword: Animal Communication; Language
Link ID: 27346 - Posted: 07.06.2020

Jason Bruck Human actions have taken a steep toll on whales and dolphins. Some studies estimate that small whale abundance, which includes dolphins, has fallen 87% since 1980 and thousands of whales die from rope entanglement annually. But humans also cause less obvious harm. Researchers have found changes in the stress levels, reproductive health and respiratory health of these animals, but this valuable data is extremely hard to collect. To better understand how people influence the overall health of dolphins, my colleagues and I at Oklahoma State University’s Unmanned Systems Research Institute are developing a drone to collect samples from the spray that comes from their blowholes. Using these samples, we will learn more about these animals’ health, which can aid in their conservation. Today, researchers wanting to measure wild dolphins’ health primarily use remote biopsy darting – where researchers use a small dart to collect a sample of tissue – or handle the animals in order to collect samples. These methods don’t physically harm the animals, but despite precautions, they can be disruptive and stressful for dolphins. Additionally, this process is challenging, time-consuming and expensive. My current research focus is on dolphin perception – how they see, hear and sense the world. Using my experience, I am part of a team building a drone specifically designed to be an improvement over current sampling methods, both for dolphins and the researchers. Our goal is to develop a quiet drone that can fly into a dolphin’s blind spot and collect samples from the mucus that is mixed with water and air sprayed out of a dolphin’s blowhole when they exhale a breath. This is called the blow. Dolphins would experience less stress and teams could collect more samples at less expense. © 2010–2020, The Conversation US, Inc.

Keyword: Learning & Memory; Evolution
Link ID: 27342 - Posted: 07.02.2020

By Bruce Bower An aptitude for mentally stringing together related items, often cited as a hallmark of human language, may have deep roots in primate evolution, a new study suggests. In lab experiments, monkeys demonstrated an ability akin to embedding phrases within other phrases, scientists report June 26 in Science Advances. Many linguists regard this skill, known as recursion, as fundamental to grammar (SN: 12/4/05) and thus peculiar to people. But “this work shows that the capacity to represent recursive sequences is present in an animal that will never learn language,” says Stephen Ferrigno, a Harvard University psychologist. Recursion allows one to elaborate a sentence such as “This pandemic is awful” into “This pandemic, which has put so many people out of work, is awful, not to mention a health risk.” Ferrigno and colleagues tested recursion in both monkeys and humans. Ten U.S. adults recognized recursive symbol sequences on a nonverbal task and quickly applied that knowledge to novel sequences of items. To a lesser but still substantial extent, so did 50 U.S. preschoolers and 37 adult Tsimane’ villagers from Bolivia, who had no schooling in math or reading. Those results imply that an ability to grasp recursion must emerge early in life and doesn’t require formal education. Three rhesus monkeys lacked humans’ ease on the task. But after receiving extra training, two of those monkeys displayed recursive learning, Ferrigno’s group says. One of the two animals ended up, on average, more likely to form novel recursive sequences than about three-quarters of the preschoolers and roughly half of the Bolivian villagers. © Society for Science & the Public 2000–2020.

Keyword: Language; Evolution
Link ID: 27332 - Posted: 06.27.2020

By Jack J. Lee For some bottlenose dolphins, finding a meal may be about who you know. Dolphins often learn how to hunt from their mothers. But when it comes to at least one foraging trick, Indo-Pacific bottlenose dolphins in Western Australia’s Shark Bay pick up the behavior from their peers, researchers argue in a report published online June 25 in Current Biology. While previous studies have suggested that dolphins learn from peers, this study is the first to quantify the importance of social networks over other factors, says Sonja Wild, a behavioral ecologist at the University of Konstanz in Germany. Cetaceans — dolphins, whales and porpoises — are known for using clever strategies to round up meals. Humpback whales (Megaptera novaeangliae) off Alaska sometimes use their fins and circular bubble nets to catch fish (SN: 10/15/19). At Shark Bay, Indo-Pacific bottlenose dolphins (Tursiops aduncus) use sea sponges to protect their beaks while rooting for food on the seafloor, a strategy the animals learn from their mothers (SN: 6/8/05). These Shark Bay dolphins also use a more unusual tool-based foraging method called shelling. A dolphin will trap underwater prey in a large sea snail shell, poke its beak into the shell’s opening, lift the shell above the water’s surface and shake the contents into its mouth. © Society for Science & the Public 2000–2020.

Keyword: Learning & Memory; Evolution
Link ID: 27328 - Posted: 06.26.2020

By Elizabeth Pennisi Though not much bigger than a wooden match stick, snapping shrimp (Alpheus heterochaelis, pictured) are already famous for their loud, quick closing claws, the sound of which stuns their prey and rivals. Now, researchers have discovered these marine crustaceans have the eyesight to match this speed. In the new study, scientists stuck a thin conducting wire into the eye of a chilled, live shrimp and recorded electrical impulses from the eye in response to flickering light. The crustaceans refresh their view 160 times a second, the team reports today in Biology Letters. That’s one of the highest refresh rates of any animal on Earth. Pigeons come close, being able to sample their field of view 143 times per second, whereas humans top out at a relatively measly 60 times a second. Only some day-flying insects beat the snapping shrimp, the researchers report. As a result, what people—perhaps even Superman—and all other vertebrates see as a blur, the shrimp detects as discrete images moving across its field of vision. Until a few years ago, most researchers assumed snapping shrimp didn’t see very well because they have a hard hood called a carapace that extends over their eyes. Although the hood seems transparent, with some coloration, it wasn’t clear how well it transmitted light. But it appears to be no impediment to the shrimp detecting fast moving prey or even predators whipping by. This might be important because the shrimp tend to live in cloudy water, so they don’t have much notice when another critter is approaching them. Posted in: © 2020 American Association for the Advancement of Science.

Keyword: Vision; Evolution
Link ID: 27318 - Posted: 06.24.2020

By Elizabeth Preston A clown fish uses his fins to fan water across a glistening mass of eggs, keeping them aerated. A silver arowana scoops up his fertilized eggs with his mouth and holds them gently for two months, until a host of miniature adults swims free from his jaws. A seahorse drifts through coral, his belly pouch swollen with unborn young. Most fish are uninvolved parents. They dump their eggs and sperm, then swim off and let nature take its course. But some species of fish take their parental duties more seriously — and among them, the majority of caring parents are dads. Care from mothers, or from both parents at once, is much less common. In a study published last fall in Evolution, researchers found evidence that paternal care, the system in which dads are the sole caretakers, has evolved dozens of times in fish. These fish aren’t exactly helicopter dads. Their most common parenting style is simply guarding eggs after they’re fertilized. “Some people are surprised this is considered care,” said Frieda Benun Sutton, an evolutionary biologist at the City University of New York. But it does count. To learn more about why this type of care in fish usually comes from dads, Dr. Benun Sutton and her co-author, Anthony Wilson, of Brooklyn College, took a deep dive into the family history of fish parents. They started with an evolutionary tree, built by other researchers in 2017 using genetic data, that shows how almost 2,000 fish species are related. Then they mapped onto the tree all the information they could find about parental care in those species: Were young cared for by fathers, mothers, both or nobody? They also added other factors including the size and number of each fish’s eggs and how they’re fertilized. The completed tree showed that care by fathers is no evolutionary accident: It has arisen at least 30 separate times. Hundreds of the species in this sample have absent mothers and caring fathers. But why? © 2020 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 27316 - Posted: 06.22.2020

By Veronique Greenwood Hummingbirds were already impressive. They move like hurried insects, turn on aerial dimes and extract nectar from flowers with almost surgical precision. But they conceal another talent, too: seeing colors that human eyes can’t perceive. Ultraviolet light from the sun creates colors throughout the natural world that are never seen by people. But researchers working out of the Rocky Mountain Biological Laboratory reported on Monday in Proceedings of the National Academy of Sciences that untrained broad-tailed hummingbirds can use these colors to help them identify sources of food. Testing 19 pairings of colors, the team found that hummingbirds are picking up on multiple colors beyond those we can see. From the bird’s-eye view, numerous plants and feathers have these as well, suggesting that they live in a richer-hued world than we do, full of signs and messages that we never notice. Compared with the color vision of many other animals, that of humans leaves something to be desired. The perception of color relies on cone cells in the retina, each of which responds to different wavelengths of light. Humans have three kinds of cone cells, which, when light reflects off an apple, a leaf or a field of daffodils, send signals that are combined in the brain to generate the perception of red, green or yellow. Birds, however, have four types of cones, including one that is sensitive to ultraviolet light. (And they are far from the most generously endowed — mantis shrimp, for instance, have 16.) In lab experiments, birds readily pick up on UV light and UV yellow, a mixture of UV light and visible yellow wavelengths, says Mary Caswell Stoddard, a professor of evolutionary biology at Princeton University and an author of the new study. Likewise, researchers have long known that UV colors are widespread in the natural world, though we can’t see them. However, experiments to see whether wild birds would use UV colors in their daily lives had not yet been performed. © 2020 The New York Times Company

Keyword: Vision; Evolution
Link ID: 27313 - Posted: 06.22.2020

By Julia Hollingsworth, CNN (CNN)Laura Molles is so attuned to birds that she can tell where birds of some species are from just by listening to their song. She's not a real-world Dr Doolittle. She's an ecologist in Christchurch, New Zealand, who specializes in a little-known area of science: bird dialects. While some birds are born knowing how to sing innately, many need to be taught how to sing by adults -- just like humans. Those birds can develop regional dialects, meaning their songs sound slightly different depending on where they live. Think Boston and Georgia accents, but for birds. Just as speaking the local language can make it easier for humans to fit in, speaking the local bird dialect can increase a bird's chances of finding a mate. And, more ominously, just as human dialects can sometimes disappear as the world globalizes, bird dialects can be shaped or lost as cities grow. The similarities between human language and bird song aren't lost on Molles -- or on her fellow bird dialect experts. "There are wonderful parallels," said American ornithologist Donald Kroodsma, the author of "Birdsong for the Curious Naturalist: Your Guide to Listening." "Culture, oral traditions -- it's all the same." For centuries, bird song has inspired poets and musicians, but it wasn't until the 1950s that scientists really started paying attention to bird dialects. One of the pioneers of the field was a British-born behaviorist named Peter Marler, who became interested in the subject when he noticed that chaffinches in the United Kingdom sounded different from valley to valley. At first, he transcribed bird songs by hand, according to a profile of him in a Rockefeller University publication. Later, he used a sonagram, which Kroodsma describes on his website as "a musical score for birdsong." ("You really need to see these songs to believe them, our eyes are so much better than our ears," Kroodsma said.) © 2020 Cable News Network.Turner Broadcasting System, Inc.

Keyword: Language; Evolution
Link ID: 27303 - Posted: 06.17.2020

By Amanda Heidt Human beings typically don’t leave the nest until well into our teenage years—a relatively rare strategy among animals. But corvids—a group of birds that includes jays, ravens, and crows—also spend a lot of time under their parents’ wings. Now, in a parallel to humans, researchers have found that ongoing tutelage by patient parents may explain how corvids have managed to achieve their smarts. Corvids are large, big-brained birds that often live in intimate social groups of related and unrelated individuals. They are known to be intelligent—capable of using tools, recognizing human faces, and even understanding physics—and some researchers believe crows may rival apes for smarts. Meanwhile, humans continue to grow their big brains and build up their cognitive abilities during childhood, as their parents feed and protect them. “Humans are characterized by this extended childhood that affects our intelligence, but we can’t be the only ones,” says Natalie Uomini, a cognitive scientist at the Max Planck Institute for the Science of Human History. But few researchers have studied the impact of parenting throughout the juvenile years on intelligence in nonhumans. To study the link between parental care and intelligence in birds, Uomini and her team created a database detailing the life history of thousands of species, including more than 120 corvids. Compared with other birds, they found corvids spend more time in the nest before fledging, more days feeding their offspring as adults, and more of their life living among family. The results, reported last week in the Philosophical Transactions of the Royal Society B, also confirm corvids have unusually large brains compared with many other birds. Birds need to be light for flight, but a raven’s brain accounts for almost 2% of its body mass, a value similar to humans. © 2020 American Association for the Advancement of Science.

Keyword: Evolution; Intelligence
Link ID: 27295 - Posted: 06.09.2020

By Rachel Nuwer Humans are not the only animals that get drunk. Birds that gorge on fermented berries and sap are known to fall out of trees and crash into windows. Elk that overdo it with rotting apples get stuck in trees. Moose wasted on overripe crab apples get tangled in swing sets, hammocks and even Christmas lights. Elephants, though, are the animal kingdom’s most well-known boozers. One scientific paper describes elephant trainers rewarding animals with beer and other alcoholic beverages, with one elephant in the 18th century said to have drunk 30 bottles of port a day. In 1974, a herd of 150 elephants in West Bengal, India, became intoxicated after breaking into a brewery, then went on a rampage that destroyed buildings and killed five people. Despite these widespread reports, scientists have questioned whether animals — especially large ones such as elephants and elk — actually become inebriated. In 2006, researchers calculated that based on the amount of alcohol it takes to get a human drunk, a 6,600-pound elephant on a bender would have to quickly consume up to 27 liters of seven percent ethanol, the key ingredient in alcohol. Such a quantity of booze is unlikely to be obtained in the wild. Intoxicated wild elephants, the researchers concluded, must be a myth. As the lead author said at the time, “People just want to believe in drunken elephants.” If you are one who wanted to believe, a study published in April in Biology Letters might serve as your vindication. A team of scientists say that the earlier myth-busting researchers made a common mistake: They assumed that elephants would have to consume as much alcohol to get drunk as humans do. In fact, elephants are likely exceptional lightweights because they — and many other mammals — lack a key enzyme that quickly metabolizes ethanol. The findings highlight the need to consider species on an individual basis. © 2020 The New York Times Company

Keyword: Drug Abuse; Evolution
Link ID: 27261 - Posted: 05.21.2020

Dana Najjar The old riddle, “Which came first, the chicken or the egg?” is relatively easy to answer as a question about the evolution of birth in animals. Egg laying almost certainly came before live birth; the armored fish that inhabited the oceans half a billion years ago and were ancestral to all land vertebrates seem to have laid eggs. But the rest of the story is far from straightforward. Over millennia of evolution, nature has come up with only two ways for a newborn animal to come into the world. Either its mother lays it in an egg, where it can continue to grow before hatching, or it stays inside its mother until emerging as a more fully formed squirming newborn. “We have this really fundamental split,” said Camilla Whittington, a biologist at the University of Sydney. Is there some primordial reason for this strict reproductive dichotomy between egg laying (oviparity) and live birth (viviparity)? When and why did live birth evolve? These are just some of the questions that new research — including studies of a remarkable lizard that can lay eggs and bear live young at the same time — is exploring, all the while underscoring the enormous complexity and variability of sexual reproduction. Early female animals laid eggs in the sense that they released their ova into the world, often thousands at a time. Sperm released by males then fertilized some of these eggs in a hit-or-miss fashion, and the resulting embryos took their chances on surviving in the hostile world until they hatched. Many creatures, particularly small, simple ones, still reproduce this way. All Rights Reserved © 2020

Keyword: Sexual Behavior; Evolution
Link ID: 27257 - Posted: 05.20.2020

By Rachel Love Nuwer The renowned biologist E.O. Wilson once quipped, “When you have seen one bird, you have not seen them all.” The diversity of the world’s 10,000-plus bird species is truly staggering, ranging from 2.5-inch-long hummingbirds that weigh as little as a dime, to 9-foot ostriches that can kick hard enough to kill a human. For decades, though, scientists generally thought of birds as conforming to a single set of rules: Females are drab and silent, while males are flashy and boisterous. Pairs are monogamous, and in the rare event of philandering, the male always initiates. Above all, this thinking posited that all birds are automatons, with pint-sized brains that constrain intelligence. Like many presumptions humans make about nature and other species, the truth turns out to be much more complex and fascinating than we ever imagined, according to science journalist Jennifer Ackerman in “The Bird Way: A New Look at How Birds Talk, Work, Play, Parent, and Think.” A new wave of research is not only dispelling old assumptions and showing that birds do not conform to sweeping generalizations, but also revealing that they are capable of nuanced, highly intelligent behaviors that we once believed to be uniquely human (or at least belonging solely to a few fellow mammals). Ackerman walks readers through the most extreme, surprising, and thought-provoking examples of recently uncovered bird behavior. She draws on hundreds of scientific studies and dozens of interviews and field visits with leading ornithologists to lay out the new revelations, from findings that choughs kidnap and enslave young from other groups (the only record of this disturbing act outside of humans and ants), to the discovery that palm cockatoos build their own musical instruments. The result is a book written for true nature and bird lovers — as well as those interested in the origins of intelligence, sociability, deception, altruism, innovation, language, and many of the other attributes at the heart of what we consider to be human.

Keyword: Intelligence; Evolution
Link ID: 27249 - Posted: 05.16.2020

By Amanda Heidt Koalas begging firefighters for water have become emblematic of Australia’s recent wildfire woes. But aside from these unusual interactions, scientists have never been quite sure how koalas drink. Now, a new study has documented the first evidence of the clever way they stay hydrated: by licking water from the smooth bark of gum trees as it rains. Past research has suggested that because koalas spend the vast majority of their time in trees, they likely get most of their water from the eucalyptus leaves they eat. But over the course of 13 years—from 2006 to 2019—citizen scientists, ecologists, and land owners reported 46 sightings of tree-licking behavior (above) in wild koalas. Researchers reviewed video and photographic evidence, and they found that even when puddles or lakes were nearby, koalas were more likely to drink the water running down trees, they report this month in Ethology. Koalas face a number of threats, and dwindling access to water is high on the list. Australia is now experiencing its driest period on record, with higher average temperatures and fewer days of rain. If tree licking provides a significant proportion of koalas’ water needs, researchers hope their results can identify areas where water should be supplemented as the rain dries up. © 2020 American Association for the Advancement of Science.

Keyword: Drug Abuse; Evolution
Link ID: 27233 - Posted: 05.06.2020

By Susan Milius An elephant, a narwhal and a guinea pig walk into a bar. From there, things could get ugly. All three might get drunk easily, according to a new survey of a gene involved in metabolizing alcohol. They’re among the creatures affected by 10 independent breakdowns of the ADH7 gene during the history of mammal evolution. Inheriting that dysfunctional gene might make it harder for their bodies to break down ethanol, says molecular anthropologist Mareike Janiak of the University of Calgary in Canada. She and colleagues didn’t look at all the genes needed to metabolize ethanol, but the failure of this important one might allow ethanol to build up more easily in these animals’ bloodstreams, Janiak and colleagues report April 29 in Biology Letters. The carnivorous cetaceans, grain- or leaf-eating guinea pigs and most other animals that the study identified as potentially easy drunks probably don’t binge on sugary fruit and nectar that brews ethanol. Elephants, however, will feast on fruit, and the new study reopens a long-running debate over whether elephants truly get tipsy gorging on marula fruit, a relative of mangoes. Descriptions of elephants behaving oddly after binging on overripe fruit go back at least to 1875, Janiak says. Later, a taste test offering the animals troughs of water spiked with ethanol found that elephants willingly drank. Afterward, they swayed more when moving and seemed more aggressive, observers reported. © Society for Science & the Public 2000–2020.

Keyword: Drug Abuse; Evolution
Link ID: 27230 - Posted: 05.05.2020

By Asher Elbein Rufous treepies, birds in the crow family native to South and Southeast Asia, usually eat insects, seeds or fruits. But some of them have learned to eat fire. Well, not exactly, but close. At a small temple in the Indian state of Gujarat, the caretakers regularly set out small votive candles made with clarified butter. The birds flit down to steal the candles, extinguish the butter-soaked wicks with a quick shake of their heads and then gulp them down. This willingness to experiment with new foods and ways of foraging is an indicator of behavioral flexibility, and some scientists think it is evidence that certain species of birds might be less vulnerable to extinction. “The idea is that if a species has individuals that are capable of these novel behaviors, they’ll respond with changes in their behavior more easily than individuals from species that do not tend to produce novel behaviors like that,” said Louis Lefebvre, a professor at McGill University in Montreal and an author on the study. “The idea is pretty simple. The problem was to be able to test it in a convincing way.” A team of researchers, led by Simon Ducatez of Spain’s Center for Research on Ecology and Forestry Applications and including Dr. Lefebvre, combed through 204 ornithological journals for mentions of novel behaviors and feeding innovations, comparing the number of sightings in each species with their risk of extinction. Their results were published this month in Nature Ecology & Evolution. Dr. Lefebvre said the approach provided backup to earlier cognition experiments he had led with wild-caught birds, such as testing their ability to figure out how to open boxes full of food. © 2020 The New York Times Company

Keyword: Learning & Memory; Evolution
Link ID: 27220 - Posted: 04.29.2020

By Ann Gibbons If you think you got your freckles, red hair, or even narcolepsy from a Neanderthal in your family tree, think again. People around the world do carry traces of Neanderthals in their genomes. But a study of tens of thousands of Icelanders finds their Neanderthal legacy had little or no impact on most of their physical traits or disease risk. Paleogeneticists realized about 10 years ago that most Europeans and Asians inherited 1% to 2% of their genomes from Neanderthals. And Melanesians and Australian Aboriginals get another 3% to 6% of their DNA from Denisovans, Neanderthal cousins who ranged across Asia 50,000 to 200,000 years ago or so. A steady stream of studies suggested gene variants from these archaic peoples might raise the risk of depression, blood clotting, diabetes, and other disorders in living people. The archaic DNA may also be altering the shape of our skulls; boosting our immune systems; and influencing our eye color, hair color, and sensitivity to the Sun, according to scans of genomic and health data in biobanks and medical databases. But the new study, which looked for archaic DNA in living Icelanders, challenges many of those claims. Researchers from Aarhus University in Denmark scanned the full genomes of 27,566 Icelanders in a database at deCODE Genetics in Iceland, seeking unusual archaic gene variants. The researchers ended up with a large catalog of 56,000 to 112,000 potentially archaic variants—and a few surprises. They found, for example, that Icelanders had inherited 3.3% of their archaic DNA from Denisovans and 12.2% from unknown sources. (84.5% came from close relatives of the reference Neanderthals.) © 2020 American Association for the Advancement of Science.

Keyword: Evolution; Genes & Behavior
Link ID: 27211 - Posted: 04.24.2020