Chapter 6. Evolution of the Brain and Behavior

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By Erika Engelhaupt To Charles Darwin, nature had a certain order. And in that order, males always came out on top. They were the leaders, the innovators, the wooers and the doers. “The males of almost all animals have stronger passions than the females,” Darwin wrote in 1871. “The female, on the other hand, with the rarest of exceptions, is less eager.” The founder of evolutionary theory posited that throughout the animal kingdom, males are active, females are passive, and that’s pretty much that. Females, in sum, are boring. That’s poppycock, Lucy Cooke writes in her latest book, Bitch. This blinkered view of nature as a man’s world was conceived and promulgated by Victorian men who imposed their values and world view on animals, she says. Cooke, a documentary filmmaker and the author of The Truth About Animals and two children’s books (SN: 4/14/18, p. 26), has traveled the world and met scientists who are exposing the truth about the sexes. She takes readers on a wild ride as she observes the ridiculous mating rituals of sage grouse, searches for orca poop (to monitor sex hormones) and watches female lemurs boss around males. Through such adventures, Cooke learns that females are anything but boring. “Female animals are just as promiscuous, competitive, aggressive, dominant and dynamic as males,” she writes. That may not sound radical to today’s feminists, but in the field of evolutionary biology, such a pronouncement has long bordered on the heretical. Generations of biologists have focused on male behavior and physiology, on the assumption that females are little more than baby-making machines to be won over by the strongest, showiest males. © Society for Science & the Public 2000–2022.

Keyword: Sexual Behavior; Evolution
Link ID: 28372 - Posted: 06.15.2022

Philip Ball How do you spot an optimistic pig? This isn’t the setup for a punchline; the question is genuine, and in the answer lies much that is revealing about our attitudes to other minds – to minds, that is, that are not human. If the notion of an optimistic (or for that matter a pessimistic) pig sounds vaguely comical, it is because we scarcely know how to think about other minds except in relation to our own. Here is how you spot an optimistic pig: you train the pig to associate a particular sound – a note played on a glockenspiel, say – with a treat, such as an apple. When the note sounds, an apple falls through a hatch so the pig can eat it. But another sound – a dog-clicker, say – signals nothing so nice. If the pig approaches the hatch on hearing the clicker, all it gets is a plastic bag rustled in its face. What happens now if the pig hears neither of these sounds, but instead a squeak from a dog toy? An optimistic pig might think there’s a chance that this, too, signals delivery of an apple. A pessimistic pig figures it will just get the plastic bag treatment. But what makes a pig optimistic? In 2010, researchers at Newcastle University showed that pigs reared in a pleasant, stimulating environment, with room to roam, plenty of straw, and “pig toys” to explore, show the optimistic response to the squeak significantly more often than pigs raised in a small, bleak, boring enclosure. In other words, if you want an optimistic pig, you must treat it not as pork but as a being with a mind, deserving the resources for a cognitively rich life. We don’t, and probably never can, know what it feels like to be an optimistic pig. Objectively, there’s no reason to suppose that it feels like anything: that there is “something it is like” to be a pig, whether apparently happy or gloomy. Until rather recently, philosophers and scientists have been reluctant to grant a mind to any nonhuman entity. Feelings and emotions, hope and pain and a sense of self were deemed attributes that separated us from the rest of the living world. To René Descartes in the 17th century, and to behavioural psychologist BF Skinner in the 1950s, other animals were stimulus-response mechanisms that could be trained but lacked an inner life. To grant animals “minds” in any meaningful sense was to indulge a crude anthropomorphism that had no place in science. © 2022 Guardian News & Media Limited

Keyword: Evolution; Intelligence
Link ID: 28367 - Posted: 06.11.2022

Helena Horton Environment reporter Otters are able to learn from each other – but still prefer to solve some puzzles on their own, scientists have found. The semi-aquatic mammals are known to be very social and intelligent creatures, but a study by the University of Exeter has given new insight into their intellect. Researchers gave otters “puzzle boxes”, some of which contained familiar food, while others held unfamiliar natural prey – shore crab and blue mussels, which are protected by hard outer shells. For the familiar food – meatballs, a favourite with the Asian short-clawed otters in the study – the scientists had five different types of boxes, and the method to extract the food changed in each version, for example pulling a tab or opening a flap. The unfamiliar food presented additional problems because the otters did not know if the crab and mussels were safe to eat and had no experience of getting them out of their shells. In order to decide whether food was safe and desirable to eat, the otters, which live at Newquay zoo and the Tamar Otter and Wildlife Centre, watched intently as their companions inspected what was in the boxes and copied if the other otters sampled the treats. However, they spent more time trying to figure out how to remove the meat from the shells on their own and relied less on the actions of their companions. Of the 20 otters in the study, 11 managed to extract the meat from all three types of natural prey. © 2022 Guardian News & Media Limited

Keyword: Learning & Memory; Evolution
Link ID: 28360 - Posted: 06.09.2022

By Jack Tamisiea Sign up for Science Times Get stories that capture the wonders of nature, the cosmos and the human body. Get it sent to your inbox. Since the days of Charles Darwin, the long necks of giraffes have been a textbook example of evolution. The theory goes that as giraffe ancestors competed for food, those with longer necks were able to reach higher leaves, getting a leg — or neck — up over shorter animals. But a bizarre prehistoric giraffe relative reveals that fighting may have driven early neck evolution in addition to foraging. In a study published Thursday in Science, a team of paleontologists described Discokeryx xiezhi, a giraffe ancestor, as having helmet-like headgear and bulky neck vertebrae. Discokeryx was adapted to absorb and deliver skull-cracking collisions to woo mates and vanquish rivals. “It shows that giraffe evolution is not just elongating the neck,” said Jin Meng, a paleontologist at the American Museum of Natural History and co-author of the new study. “Discokeryx goes in a totally different direction.” Dr. Meng and his colleagues discovered the fossils in an outcrop of rock in northwestern China called the Junggar Basin. Around 17 million years ago, this area was an expanse of savannas and forests home to an array of large mammals like shovel-tusked elephants, short-horned rhinoceroses and burly bear dogs. While exploring this bonebed in 1996, Dr. Meng stumbled across a hunk of skull. He could tell it was a mammalian braincase, but the top was flattened like an iron press. Without more of the animal’s skeleton, Dr. Meng and his colleagues referred to it as the “strange beast.” © 2022 The New York Times Company

Keyword: Evolution; Aggression
Link ID: 28350 - Posted: 06.04.2022

ByVirginia Morell Babies don’t babble to sound cute—they’re taking their first steps on the path to learning language. Now, a study shows parrot chicks do the same. Although the behavior has been seen in songbirds and two mammalian species, finding it in these birds is important, experts say, as they may provide the best nonhuman model for studying how we begin to learn language. The find is “exciting,” says Irene Pepperberg, a comparative psychologist at Hunter College not involved with the work. Pepperberg herself discovered something like babbling in a famed African gray parrot named Alex, which she studied for more than 30 years. By unearthing the same thing in another parrot species and in the wild, she says, the team has shown this ability is widespread in the birds. In this study, the scientists focused on green-rumped parrotlets (Forpus passerinus)—a smaller species than Alex, found from Venezuela to Brazil. The team investigated a population at Venezuela’s Hato Masaguaral research center, where scientists maintain more than 100 artificial nesting boxes. Like other parrots, songbirds, and humans (and a few other mammal species), parrotlets are vocal learners. They master their calls by listening and mimicking what they hear. The chicks in the new study started to babble at 21 days, according to camcorders installed in a dozen of their nests. They increased the complexity of their sounds dramatically over the next week, the scientists report today in the Proceedings of the Royal Society B. The baby birds uttered strings of soft peeps, clicks, and grrs, but they weren’t communicating with their siblings or parents, says lead author Rory Eggleston, a Ph.D. student at Utah State University. Rather, like a human infant babbling quietly in their crib, a parrotlet chick made the sounds alone (see video). Indeed, most chicks started their babbling bouts when their siblings were asleep, often doing so without even opening their beaks, says Eggleston, who spent hours analyzing videos of the birds. © 2022 American Association for the Advancement of Science.

Keyword: Language; Animal Communication
Link ID: 28343 - Posted: 06.01.2022

By Laura Sanders Punishing headbutts damage the brains of musk oxen. That observation, made for the first time and reported May 17 in Acta Neuropathologica, suggests that a life full of bell-ringing clashes is not without consequences, even in animals built to bash. Although a musk ox looks like a dirty dust mop on four tiny hooves, it’s formidable. When charging, it can reach speeds up to 60 kilometers an hour before ramming its head directly into an oncoming head. People expected that musk oxen brains could withstand these merciless forces largely unscathed, “that they were magically perfect,” says Nicole Ackermans of the Icahn School of Medicine at Mount Sinai in New York City. “No one actually checked.” In fact, the brains of three wild musk oxen (two females and one male) showed signs of extensive damage, Ackermans and her colleagues found. The damage was similar to what’s seen in people with chronic traumatic encephalopathy, a disorder known to be caused by repetitive head hits (SN: 12/13/17). In the musk ox brains, a form of a protein called tau had accumulated in patterns that suggested brain bashing was to blame. In an unexpected twist, the brains of the females, who hit heads less frequently than males, were worse off than the male’s. The male body, with its heavier skull, stronger neck muscles and forehead fat pads, may cushion the blows to the brain, the researchers suspect. The results may highlight an evolutionary balancing act; the animals can endure just enough brain damage to allow them to survive and procreate. High-level brainwork may not matter much, Ackermans says. “Their day-to-day life is not super complicated.” © Society for Science & the Public 2000–2022.

Keyword: Brain Injury/Concussion; Evolution
Link ID: 28341 - Posted: 05.28.2022

By Tess Joosse The mere sight of another person yawning causes many of us to open our mouths wide in mimicry. And we’re not alone—other social animals, such aschimpanzees and lions, can also catch so-called contagious yawns. It’s likely that all vertebrates yawn spontaneously to regulate inner body processes. Yawning probably arose with the evolution of jawed fishes 400 million or so years ago, says Andrew Gallup, an evolutionary biologist at State University of New York Polytechnic Institute who has spent years trying to figure out why we yawn. In a paper published this month in Animal Behavior, he reports some evidence for how contagious yawns might have evolved to keep us safe. Science chatted with Gallup about why yawning is ubiquitous—and useful. This interview has been edited for clarity and length. Q: First, let’s address a long-standing myth: Does yawning increase blood oxygen levels? A: No. Despite continued belief, research has explicitly tested that hypothesis and the results have concluded that breathing and yawning are controlled by different mechanisms. For example, there are really interesting cases of yawning in marine mammals, where the yawning occurs while the animal is submerged underwater and therefore not breathing. Q: So what does yawning actually do to the body? A: Yawning is a rather complex reflex. It’s triggered under a variety of contexts and neurophysiological changes. It primarily occurs during periods of state change, commonly following transitions of sleeping and waking. There’s research that also suggests that yawns are initiated alongside increases in cortical arousal, so yawns themselves may function to promote alertness. And there’s a growing body of research that suggests that yawning is triggered by rises in brain temperature. I’ve conducted a number of studies testing this in humans, nonhuman mammals, and even birds. © 2022 American Association for the Advancement of Science.

Keyword: Emotions; Evolution
Link ID: 28337 - Posted: 05.25.2022

By Veronique Greenwood Lovebirds, small parrots with vibrant rainbow plumage and cheeky personalities, are popular pets. They swing from ropes, cuddle with companions and race for treats in a waddling gait with all the urgency of toddlers who spot a cookie. But, along with other parrots, they also do something strange: They use their faces to climb walls. Give these birds a vertical surface to clamber up, and they cycle between left foot, right foot and beak as if their mouths were another limb. In fact, a new analysis of the forces climbing lovebirds exert reveals that this is precisely what they are doing. Somehow, a team of scientists wrote in the journal Proceedings of the Royal Society B on Wednesday, the birds and perhaps other parrot species have repurposed the muscles in their necks and heads so they can walk on their beaks, using them the way rock climbers use their arms. Climbing with a beak as a third limb is peculiar because third limbs generally are not something life on Earth is capable of producing, said Michael Granatosky, an assistant professor of anatomy at the New York Institute of Technology and an author of the new paper. “There is this very deep, deep set aspect of our biology that everything is bilateral” in much of the animal kingdom, he said. The situation makes it developmentally unlikely to grow an odd numbers of limbs for walking. Some animals have developed workarounds. Kangaroos use their tails as a fifth limb when hopping slowly, pushing off from the ground with their posteriors the same way they push with their feet. To see if parrots were using their beaks in a similar way, Dr. Granatosky and a graduate student, Melody Young, as well as their colleagues brought six rosy-faced lovebirds from a pet store into the lab. They had the birds climb up a surface that was fitted with a sensor to keep track of how much force they were exerting and in what directions. The scientists found that the propulsive force the birds applied through their beaks was similar to what they provided with their legs. What had started as a way to eat had transformed into a way to walk, with beaks as powerful as their limbs. © 2022 The New York Times Company

Keyword: Evolution
Link ID: 28336 - Posted: 05.25.2022

By Anna Gibbs Cradled inside the hushed world of the womb, fetuses might be preparing to come out howling. In the same way newborn humans can cry as soon as they’re born, common marmoset monkeys (Callithrix jacchus) produce contact calls to seek attention from their caregivers. Those vocalizations are not improv, researchers report in a preprint posted April 14 at bioRxiv. Ultrasound imaging of marmoset fetuses reveals that their mouths are already mimicking the distinctive pattern of movements used to emit their first calls, long before the production of sound. Early behaviors in infants are commonly described as “innate” or “hard-wired,” but a team at Princeton University wondered how exactly those behaviors develop. How does a baby know how to cry as soon as it’s born? The secret may lie in what’s happening before birth. “People tend to ignore the fetal period,” says Darshana Narayanan, a behavioral neuroscientist who did the research while at Princeton University. “They just think that it’s like the baby’s just vegetating and waiting to be born…. [But] that’s where many things begin.” Research shows, for instance, that chicks inside their eggs are already learning to identify their species’ call (SN: 9/16/21). “So much is developing so much earlier in development than we previously thought,” says developmental psychobiologist Samantha Carouso-Peck, executive director of Grassland Bird Trust in Fort Edward, N.Y., who was not involved in the research. But, she says, “we really haven’t looked much at all at the production side of this. Most of what we know is the auditory side.” Carouso-Peck studies vocal learning in songbirds and how it applies to how humans acquire language. © Society for Science & the Public 2000–2022.

Keyword: Animal Communication; Language
Link ID: 28325 - Posted: 05.11.2022

Freda Kreier Some bats can imitate the sound of buzzing hornets to scare off owls, researchers say. The discovery is the first documented case of a mammal mimicking an insect to deter predators. Many animals copy other creatures in a bid to make themselves seem less palatable to predators. Most of these imitations are visual. North America’s non-venomous scarlet kingsnake (Lampropeltis elapsoides), for instance, has evolved to have similar colour-coding to the decidedly more dangerous eastern coral snake (Micrurus fulvius). Now, a study comparing the behaviour of owls exposed to insect and bat noises suggests that greater mouse-eared bats (Myotis myotis) might be among the few animals to have weaponized another species’ sound, says co-author Danilo Russo, an animal ecologist at the University of Naples Federico II in Italy. “When we think of mimicry, the first thing that comes to mind is colour, but in this case, it is sound that plays a crucial role,” he adds. The research was published on 9 May in Current Biology1. Because they are nocturnal and have poor eyesight, most bats rely on echolocation to find their way around, and communicate using a wide array of other noises. Russo first noticed that the distress call of the greater mouse-eared bat sounded like the buzzing of bees or hornets while he was catching the bats for a different research project. To investigate whether other animals might make the same connection, Russo and his colleagues compared the sound structure of buzzing by the European hornet (Vespa crabro) to that of the bat’s distress call. At most frequencies, the two sounds were not dramatically similar, but they were when the bat’s call was stripped down to include only frequencies that owls — one of the animal’s main predators — are able to hear. This suggests that the distress call as heard by owls strongly resembles the buzzing of a hornet, Russo says, so it could fool predators. © 2022 Springer Nature Limited

Keyword: Hearing; Evolution
Link ID: 28324 - Posted: 05.11.2022

Erin Spencer The octopus is one of the coolest animals in the sea. For starters, they are invertebrates. That means they don’t have backbones like humans, lions, turtles and birds. Understand new developments in science, health and technology, each week That may sound unusual, but actually, nearly all animals on Earth are invertebrates – about 97%. Octopuses are a specific type of invertebrate called cephalopods. The name means “head-feet” because the arms of cephalopods surround their heads. Other types of cephalopods include squid, nautiloids and cuttlefish. As marine ecologists, we conduct research on how ocean animals interact with each other and their environments. We’ve mostly studied fish, from lionfish to sharks, but we have to confess we remain captivated by octopuses. What octopuses eat depends on what species they are and where they live. Their prey includes gastropods, like snails and sea slugs; bivalves, like clams and mussels; crustaceans, like lobsters and crabs; and fish. To catch their food, octopuses use lots of strategies and tricks. Some octopuses wrap their arms – not tentacles – around prey to pull them close. Some use their hard beak to drill into the shells of clams. All octopuses are venomous; they inject toxins into their prey to overpower and kill them. There are about 300 species of octopus, and they’re found in every ocean in the world, even in the frigid waters around Antarctica. A special substance in their blood helps those cold-water species get oxygen. It also turns their blood blue. © 2010–2022, The Conversation US, Inc.

Keyword: Evolution; Intelligence
Link ID: 28321 - Posted: 05.11.2022

By Elizabeth Preston On dry nights, the San hunter-gatherers of Namibia often sleep under the stars. They have no electric lights or new Netflix releases keeping them awake. Yet when they rise in the morning, they haven’t gotten any more hours of sleep than a typical Western city-dweller who stayed up doom-scrolling on their smartphone. Research has shown that people in non-industrial societies — the closest thing to the kind of setting our species evolved in — average less than seven hours a night, says evolutionary anthropologist David Samson at the University of Toronto Mississauga. That’s a surprising number when you consider our closest animal relatives. Humans sleep less than any ape, monkey or lemur that scientists have studied. Chimps sleep around 9.5 hours out of every 24. Cotton-top tamarins sleep around 13. Three-striped night monkeys are technically nocturnal, though really, they’re hardly ever awake — they sleep for 17 hours a day. Samson calls this discrepancy the human sleep paradox. “How is this possible, that we’re sleeping the least out of any primate?” he says. Sleep is known to be important for our memory, immune function and other aspects of health. A predictive model of primate sleep based on factors such as body mass, brain size and diet concluded that humans ought to sleep about 9.5 hours out of every 24, not seven. “Something weird is going on,” Samson says. Research by Samson and others in primates and non-industrial human populations has revealed the various ways that human sleep is unusual. We spend fewer hours asleep than our nearest relatives, and more of our night in the phase of sleep known as rapid eye movement, or REM. The reasons for our strange sleep habits are still up for debate but can likely be found in the story of how we became human. Graph shows average time spent sleep of different primate species. Humans sleep the least at seven hours per night; the three-striped night monkey sleeps the most at nearly 17 hours. © 2022 Annual Reviews

Keyword: Sleep; Evolution
Link ID: 28310 - Posted: 04.30.2022

By Lisa Feldman Barrett Do your facial movements broadcast your emotions to other people? If you think the answer is yes, think again. This question is under contentious debate. Some experts maintain that people around the world make specific, recognizable faces that express certain emotions, such as smiling in happiness, scowling in anger and gasping with widened eyes in fear. They point to hundreds of studies that appear to demonstrate that smiles, frowns, and so on are universal facial expressions of emotion. They also often cite Charles Darwin’s 1872 book The Expression of the Emotions in Man and Animals to support the claim that universal expressions evolved by natural selection. Other scientists point to a mountain of counterevidence showing that facial movements during emotions vary too widely to be universal beacons of emotional meaning. People may smile in hatred when plotting their enemy’s downfall and scowl in delight when they hear a bad pun. In Melanesian culture, a wide-eyed gasping face is a symbol of aggression, not fear. These experts say the alleged universal expressions just represent cultural stereotypes. To be clear, both sides in the debate acknowledge that facial movements vary for a given emotion; the disagreement is about whether there is enough uniformity to detect what someone is feeling. This debate is not just academic; the outcome has serious consequences. Today you can be turned down for a job because a so-called emotion-reading system watching you on camera applied artificial intelligence to evaluate your facial movements unfavorably during an interview. In a U.S. court of law, a judge or jury may sometimes hand down a harsher sentence, even death, if they think a defendant’s face showed a lack of remorse. Children in preschools across the country are taught to recognize smiles as happiness, scowls as anger and other expressive stereotypes from books, games and posters of disembodied faces. And for children on the autism spectrum, some of whom have difficulty perceiving emotion in others, these teachings do not translate to better communication. © 2022 Scientific American,

Keyword: Emotions; Evolution
Link ID: 28306 - Posted: 04.30.2022

Natalia Mesa Cravings for sugary treats and other “wants” in humans are driven by the activity of dopamine-producing cells in our mesolimbic system. Experimental research now suggests that a similar system might also exist in honeybees (Apis mellifera), spurring them to “want” to search for sources of nectar. In a study published today (April 28) in Science, researchers found that bees’ dopamine levels were elevated during the search for food and dropped once the food was consumed. Dopamine may also help trigger a hedonic, or pleasant, “memory” of the sugary treat, the researchers say, as dopamine levels rose again when foragers danced to tell other foragers about the foods’ locations. “The whole story is new. To show that there is a wanting system in insects is generally new,” says study coauthor Martin Giurfa, a neuroscientist at Paul Sabatier University in Toulouse, France. “Bees are truly amazing.” In both humans and invertebrates, dopamine is known to be involved in learning and reward. Giurfa and his team have been studying the neurotransmitter in bees, and several years ago, they characterized many of the neural pathways that involved dopamine. “We found so many so diverse pathways that we said, ‘There might be more than just representing reinforcement, representing punishment, representing reward.’” He began to look for other roles dopamine might play in honeybee behavior. bee next to pink flower © 1986–2022 The Scientist.

Keyword: Drug Abuse; Evolution
Link ID: 28305 - Posted: 04.30.2022

By Sharon Oosthoek Despite their excellent vision, one city-dwelling colony of fruit bats echolocates during broad daylight — completely contrary to what experts expected. A group of Egyptian fruit bats (Rousettus aegyptiacus) in downtown Tel Aviv uses sound to navigate in the middle of the day, researchers report in the April 11 Current Biology. The finding greatly extends the hours during which bats from this colony echolocate. A few years ago, some team members had noticed bats clicking while they flew under low-light conditions. The midday sound-off seems to help the bats forage and navigate, even though they can see just fine. Bats that are active during the day are unusual. Out of the more than 1,400 species, roughly 10 are diurnal. What’s more, most diurnal bats don’t use echolocation during the day, relying instead on their vision to forage and avoid obstacles. They save echolocation for dim light or dark conditions. So that’s why, two years ago, a group of Tel Aviv researchers were surprised when they noticed a bat smiling during the day. They were looking over photos from their latest study of Egyptian fruit bats when they noticed one with its mouth slightly parted and upturned. “When an Egyptian fruit bat is smiling, he’s echolocating — he’s producing clicks with his tongue and his mouth is open,” says Ofri Eitan, a bat researcher at Tel Aviv University. “But this was during the day, and these bats see really well.” When Eitan and his colleagues looked through other photos — thousands of them — many showed smiling bats in broad daylight. The team showed in 2015 that the diurnal Egyptian fruit bats do use echolocation outdoors under various low light conditions, at least occasionally. But the researchers hadn’t looked at whether the bats were echolocating during midday hours when light levels are highest. © Society for Science & the Public 2000–2022.

Keyword: Hearing; Evolution
Link ID: 28286 - Posted: 04.16.2022

By Jake Buehler Earthen piles built by a chicken-like bird in Australia aren’t just egg incubators — they may also be crucial for the distribution of key nutrients throughout the ecosystem. In the dry woodlands of South Australia, sandy mounds rise between patches of many-stemmed “mallee” eucalyptus trees. These monuments — big enough to smother a parking space — are nests, painstakingly constructed by the malleefowl bird. By inadvertently engineering a patchwork of nutrients and churned soil, the industrious malleefowl may be molding surrounding plant and soil communities and even blunting the spread of fire, researchers report March 27 in the Journal of Ecology. Such ecosystem impacts suggest malleefowl conservation could benefit many species, says Heather Neilly, an ecologist at the Australian Landscape Trust in Calperum Station. The species is currently listed as “vulnerable” and declining by the International Union for Conservation of Nature. Some animals — termed “ecosystem engineers” — produce habitats for other species by shaping the environment around them. Beavers build dams that create homes for pond-dwelling lifeforms. In deserts, owls and giant lizards support plant and animal life with their burrows (SN: 10/8/19; SN: 1/19/21). “In Australia in particular, the focus has largely been on our array of digging mammals,” Neilly says. But malleefowl (Leipoa ocellata) — found throughout western and southern Australia — also perturb the soil. They and their close relatives are “megapodes,” a group of fowl native to Australasia and the South Pacific that have the unusual habit of incubating their eggs much like alligators do: in a massive pile of rotting compost. Heat from the decaying vegetation — locked in with an insulating sand layer on top — regulates the eggs’ temperature, and the young scratch their way to the surface upon hatching. © Society for Science & the Public 2000–2022.

Keyword: Sexual Behavior; Evolution
Link ID: 28280 - Posted: 04.13.2022

By Annie Roth and Hisako Ueno The reign of Japan’s monkey queen has just begun. Last year, Yakei, a 9-year-old female Japanese macaque, fought several other macaques, including her own mother, to become the alpha of her troop. That made Yakei the first known female troop leader in the history of Takasakiyama Natural Zoological Garden in Southern Japan, which was established in 1952 and is home to over 1,000 macaques. But during her first breeding season as queen, which began in November 2021 and concluded in March 2022, a messy love triangle threatened to weaken her grip on power. According to officials at the park, the macaque that Yakei showed interest in mating with, a 15-year-old male named Goro, rejected her advances despite their coupling during a previous breeding season. Meanwhile, an 18-year-old macaque named Luffy did his best to woo Yakei, much to her displeasure. Japanese macaques are polyamorous and scientists were worried that Yakei would not be able to maintain her status while pursuing and rejecting potential mates. Tensions run high during breeding season, and a challenge from a spurned male could easily rob Yakei, an average-sized female, of her rank. Yakei rose to power by defeating her troop’s alpha male, but he was elderly and less formidable than the average young male. Fortunately for Yakei, no other macaques attempted to usurp her throne this season and the queen remained the troop’s alpha at the end of March, according to reserve officials. Her continued rule has surprised scientists and given them an opportunity to observe how macaque society functions under a matriarchy. Despite having to maintain her supremacy, Yakei managed to have a successful breeding season. After Goro gave her the cold shoulder, she spent many weeks playing the field, expressing interest in no fewer than five males. Among these males was Chris, a male ranked 10th in the troop, and Shikao, who holds the rank just below Chris. But the only male the reserve is sure she mated with was Maruo. Maruo, Yakei’s mate. © 2022 The New York Times Company

Keyword: Aggression; Sexual Behavior
Link ID: 28279 - Posted: 04.13.2022

By Alla Katsnelson A dog gives a protective bark, sensing a nearby stranger. A cat slinks by disdainfully, ignoring anyone and everyone. A cow moos in contentment, chewing its cud. At least, that’s what we may think animals feel when they act the way they do. We take our own lived experiences and fill in gaps with our imaginations to better understand and relate to the animals we encounter. Often, our assumptions are wrong. Take horse play, for example. Many people assume that these muscular, majestic animals are roughhousing just for the fun of it. But in the wild, adult horses rarely play. When we see them play in captivity, it isn’t necessarily a good sign, says Martine Hausberger, an animal scientist at CNRS at the University of Rennes in France. Hausberger, who raises horses on her farm in Brittany, began studying horse welfare about three decades ago, after observing that people who keep horses often misjudge cues about the animals’ behavior. Adult horses that play are often ones that have been restrained, Hausberger says. Play seems to discharge the stress from that restriction. “When they have the opportunity, they may exhibit play, and at that precise moment they may be happier,” she says. But “animals that are feeling well all the time don’t need this to get rid of the stress.” Scientists studying animal behavior and animal welfare are making important strides in understanding how the creatures we share our planet with experience the world. “In the last decade or two, people have gotten bolder and more creative in terms of asking what animals’ emotional states are,” explains Georgia Mason, a behavioral biologist and animal welfare scientist at the University of Guelph in Canada. They’re finding thought-provoking answers amid a wide array of animals. © Society for Science & the Public 2000–2022.

Keyword: Emotions; Evolution
Link ID: 28276 - Posted: 04.09.2022

ByTess Joosse My dog Leo clearly knows the difference between my voice and the barks of the beagle next door. When I speak, he looks at me with love; when our canine neighbor makes his mind known, Leo barks back with disdain. A new study backs up what I and my fellow dog owners have long suspected: Dogs’ brains process human and canine vocalizations differently, suggesting they evolved to recognize our voices from their own. “The fact that dogs use auditory information alone to distinguish between human and dog sound is significant,” says Jeffrey Katz, a cognitive neuroscientist at Auburn University who is not involved with the work. Previous research has found that dogs can match human voices with expressions. When played an audio clip of a lady laughing, for example, they’ll often look at a photo of a smiling woman. But how exactly the canine brain processes sounds isn’t clear. MRI has shown certain regions of the dog brain are more active when a pup hears another dog whine or bark. But those images can’t reveal exactly when neurons in the brain are firing, and whether they fire differently in response to different noises. So in the new study, Anna Bálint, a canine neuroscientist at Eötvös Loránd University, turned to an electroencephalogram, which can measure individual brain waves. She and her colleagues recruited 17 family dogs, including several border collies, golden retrievers, and a German shepherd, that were previously taught to lie still for several minutes at a time. The scientists attached electrodes to each dog’s head to record its brain response—not an easy task, it turns out. Unlike humans’ bony noggins, dog heads have lots of muscles that can obstruct a clear readout, Bálint says. © 2022 American Association for the Advancement of Science.

Keyword: Language; Animal Communication
Link ID: 28270 - Posted: 04.06.2022

By Carolyn Gramling Modern mammals are known for their big brains. But new analyses of mammal skulls from creatures that lived shortly after the dinosaur mass extinction shows that those brains weren’t always a foregone conclusion. For at least 10 million years after the dinosaurs disappeared, mammals got a lot brawnier but not brainier, researchers report in the April 1 Science. That bucks conventional wisdom, to put it mildly. “I thought, it’s not possible, there must be something that I did wrong,” says Ornella Bertrand, a mammal paleontologist at the University of Edinburgh. “It really threw me off. How am I going to explain that they were not smart?” Modern mammals have the largest brains in the animal kingdom relative to their body size. How and when that brain evolution happened is a mystery. One idea has been that the disappearance of all nonbird dinosaurs following an asteroid impact at the end of the Mesozoic Era 66 million years ago left a vacuum for mammals to fill (SN: 1/25/17). Recent discoveries of fossils dating to the Paleocene — the immediately post-extinction epoch spanning 66 million to 56 million years ago — does reveal a flourishing menagerie of weird and wonderful mammal species, many much bigger than their Mesozoic predecessors. It was the dawn of the Age of Mammals. Before those fossil finds, the prevailing wisdom was that in the wake of the mass dino extinction, mammals’ brains most likely grew apace with their bodies, everything increasing together like an expanding balloon, Bertrand says. But those discoveries of Paleocene fossil troves in Colorado and New Mexico, as well as reexaminations of fossils previously found in France, are now unraveling that story, by offering scientists the chance to actually measure the size of mammals’ brains over time. © Society for Science & the Public 2000–2022.

Keyword: Evolution
Link ID: 28266 - Posted: 04.02.2022