Chapter 6. Evolution of the Brain and Behavior

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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

Christie Wilcox Sex might be biology’s most difficult enigma. The downsides of relying on sex to reproduce are undeniable: It takes two individuals, each of whom gets to pass on only part of their genome. Because these individuals generally have to get fairly intimate, they make themselves vulnerable to physical harm or infections from their partner. Asexual reproduction, or self-cloning, has none of these disadvantages. Clones can be made anywhere and anytime, and they receive the full complement of an individual’s genes. Yet despite all its benefits, asexual reproduction is the exception, not the norm, among organisms that have compartmentalized cells (eukaryotes). In plants, for example — which are somewhat known for their genetic flexibility — less than 1% of species are thought to reproduce asexually often. Among animals, only one out of every thousand known species is exclusively asexual. For centuries, biologists have pondered this apparent paradox. In 1932, the geneticist Hermann Muller, whose work on radiation-induced mutations would eventually garner a Nobel Prize, believed he had the answer. “Genetics has finally solved the age-old problem of the reason for the existence (i.e., the function) of sexuality and sex,” he boasted in The American Naturalist. He went on to explain, “Sexuality, through recombination, is a means for making the fullest use of the possibilities of gene mutations.” All Rights Reserved © 2020

Keyword: Sexual Behavior; Evolution
Link ID: 27210 - Posted: 04.24.2020

By John Pickrell Joseph Schubert spends hours at a time lying in the dirt of the Australian outback watching for tiny flickers in the sparse, ground-hugging foliage. The 22-year-old arachnologist is searching for flea-sized peacock spiders, and he admits, he’s a little obsessed. But it wasn’t always so. Schubert grew up fearing spiders, with parents who were “absolutely terrified” of the eight-legged crawlers. “I was taught that every single spider in the house was going to kill me, and we should squish it and get rid of it,” he says. Then Schubert stumbled across some photographs of Australia’s endemic peacock spiders, a group named for the adult males’ vivid coloring and flamboyant dance moves aimed at wooing a mate (SN: 9/9/16; SN: 12/8/15). And he was hooked. “They raise their third pair of legs and dance around and show off like they are the most amazing animals on the planet, which in my eyes they are.” He decided to pursue a career in arachnology. And despite not quite having completed his undergraduate degree in biology, he’s begun working part time at Museums Victoria in Melbourne, and has already made a mark. Of the 86 known peacock spider species — each just 2.5 to 6 millimeters in length — 12 have been described by Schubert, including seven named in the March 27 Zootaxa. Those seven were found at a range of sites across Australia, including the barren dunes and shrublands of Victoria state’s Little Desert and the red rocks and arid outback gorges of Kalbarri National Park, north of Perth. © Society for Science & the Public 2000–2020

Keyword: Sexual Behavior; Evolution
Link ID: 27202 - Posted: 04.17.2020

Gregory Berns, M.D., Ph.D. There is no official census for dogs and cats, but in 2016, the American Veterinary Medical Association estimated that 59 percent of households in the United States had a pet. Although the numbers of dogs and cats remains debatable, dogs continue to gain in popularity with 38 percent of households having at least one. Families with children are even more likely to have a dog (55 percent). With all due respect to cats, dogs have insinuated themselves into human society, forming deep emotional bonds with us and compelling us to feed and shelter them. Worldwide, the dog population is approaching one billion, the majority free-ranging. Even though many people are convinced they know what their dog is thinking, little is actually known about what is going on in dogs’ heads. This may be surprising because the field of experimental psychology had its birth with Pavlov and his salivating dogs. But as dogs gained traction as household pets, in many cases achieving the status of family members, their use as research subjects fell out of favor. In large part, this was a result of the Animal Welfare Act of 1966, which set standards for the treatment of animals in research and put an end to the practice of stealing pets for experimentation. How strange it is then that these creatures, whose nearest relatives are wolves, live with us and even share our beds, yet we know almost nothing about what they’re thinking. In the last decade or so, however, the situation has begun to change, and we are in the midst of a renaissance of canine cognitive science. Research labs have sprung up around the world, and dogs participate not as involuntary subjects, but as partners in scientific discovery. This new research is beginning to shed light on what it’s like to be a dog and the nature of the dog-human bond. © 2020 The Dana Foundation.

Keyword: Brain imaging; Evolution
Link ID: 27195 - Posted: 04.16.2020

Peter Rhys-Evans For the past 150 years, scientists and laypeople alike have accepted a “savanna” scenario of human evolution. The theory, primarily based on fossil evidence, suggests that because our ancestral ape family members were living in the trees of East African forests, and because we humans live on terra firma, our primate ancestors simply came down from the trees onto the grasslands and stood upright to see farther over the vegetation, increasing their efficiency as hunter-gatherers. In the late 19th century, anthropologists only had a few Neanderthal fossils to study, and science had very little knowledge of genetics and evolutionary changes. So this savanna theory of human evolution became ingrained in anthropological dogma and has remained the established explanation of early hominin evolution following the genetic split from our primate cousins 6 million to 7 million years ago. But in 1960, a different twist on human evolution emerged. That year, marine biologist Sir Alister Hardy wrote an article in New Scientist suggesting a possible aquatic phase in our evolution, noting Homo sapiens’s differences from other primates and similarities to other aquatic and semi-aquatic mammals. In 1967, zoologist Desmond Morris published The Naked Ape, which explored different theories about why modern humans lost their fur. Morris mentioned Hardy’s “aquatic ape” hypothesis as an “ingenious” theory that sufficiently explained “why we are so nimble in the water today and why our closest living relatives, the chimpanzees, are so helpless and quickly drown.” © 1986–2020 The Scientist

Keyword: Evolution
Link ID: 27190 - Posted: 04.15.2020

By Alexandra Horowitz Recently, in communities under quarantine or stay-at-home orders, residents have looked out their windows to find wild animals that usually stay on the fringes of the city or emerge only at night suddenly appearing in daylight in the middle of the street. The reason is us: Human activity disturbs animals. Even our presence — simply observing, as bird-watchers, or field biologists, or nature-loving hikers — changes their behavior. The ecologist Carl Safina (author of “Beyond Words” and “Song for the Blue Ocean”) is no agnostic observer. He sees humans as destroying the world for nonhuman animals, to say nothing of destroying the animals themselves, and would like us to stop, please. The question for him, and for anyone with this conviction, is: Short of quarantining the human race, what’s the best way to do this? Fifty years ago, the biologist Robert Payne first eavesdropped on a humpback whale community and heard whale song. He spread the word about their ethereal, beautiful forms of communication, and the world looked at whales differently. Since that time, whaling has sharply declined. Today, many advocates for animals appeal to species’ cognitive abilities to argue for their better treatment. They’re so smart or humanlike, the argument goes, we should be treating them better. Such is the vestige of the scala naturae that has awarded all lives a certain value — with humans on top, of course. © 2020 The New York Times Company

Keyword: Evolution
Link ID: 27185 - Posted: 04.14.2020