Chapter 6. Evolution of the Brain and Behavior

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By Darren Incorvaia The great apes do not have spoken language, but they share many gestures. Can humans like you understand those gestures too? Watch this short video and test your ability to read chimpanzee body language. What is this chimpanzee (the one scratching its arm) asking the other one to do? © 2023 The New York Times Company

Keyword: Animal Communication; Evolution
Link ID: 28640 - Posted: 01.25.2023

By Rodrigo Pérez Ortega Was Tyrannosaurus rex as smart as a baboon? Scientists don’t like to compare intelligence between species (everyone has their own talents, after all), but a controversial new study suggests some dino brains were as densely packed with neurons as those of modern primates. If so, that would mean they were very smart—more than researchers previously thought—and could have achieved feats only humans and other very intelligent animals have, such as using tools. The findings, reported last week in the Journal of Comparative Neurology, are making waves among paleontologists on social media and beyond. Some are applauding the paper as a good first step toward better understanding dinosaur smarts, whereas others argue the neuron estimates are flawed, undercutting the study’s conclusions. Measuring dinosaur intelligence has never been easy. Historically, researchers have used something called the encephalization quotient (EQ), which measures an animal’s relative brain size, related to its body size. A T. rex, for example, had an EQ of about 2.4, compared with 3.1 for a German shepherd dog and 7.8 for a human—leading some to assume it was at least somewhat smart. EQ is hardly foolproof, however. In many animals, body size evolves independently from brain size, says Ashley Morhardt, a paleoneurologist at Washington University School of Medicine in St. Louis who wasn’t involved in the study. “EQ is a fraught metric, especially when studying extinct species.” Looking for a more trustworthy alternative, Suzana Herculano-Houzel, a neuroanatomist at Vanderbilt University, turned to a different measure: the density of neurons in the cortex, the wrinkly outer brain area critical to most intelligence-related tasks. She had previously estimated the number of neurons in many animal species, including humans, by making “brain soup”—dissolving brains in a detergent solution—and counting the neurons in different parts of the brain. © 2023 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 28627 - Posted: 01.12.2023

By Elizabeth Pennisi Biologists have long known that new protein-coding genes can arise through the duplication and modification of existing ones. But some protein genes can also arise from stretches of the genome that once encoded aimless strands of RNA instead. How new protein genes surface this way has been a mystery, however. Now, a study identifies mutations that transform seemingly useless DNA sequences into potential genes by endowing their encoded RNA with the skill to escape the cell nucleus—a critical step toward becoming translated into a protein. The study’s authors highlight 74 human protein genes that appear to have arisen in this de novo way—more than half of which emerged after the human lineage branched off from chimpanzees. Some of these newcomer genes may have played a role in the evolution of our relatively large and complex brains. When added to mice, one made the rodent brains grow bigger and more humanlike, the authors report this week in Nature Ecology & Evolution. “This work is a big advance,” says Anne-Ruxandra Carvunis, an evolutionary biologist at the University of Pittsburgh, who was not involved with the research. It “suggests that de novo gene birth may have played a role in human brain evolution.” Although some genes encode RNAs that have structural or regulatory purposes themselves, those that encode proteins instead create an intermediary RNA. Made in the nucleus like other RNAs, these messenger RNAs (mRNAs) exit into the cytoplasm and travel to organelles called ribosomes to tell them how to build the gene’s proteins. A decade ago, Chuan-Yun Li, an evolutionary biologist at Peking University, and colleagues discovered that some human protein genes bore a striking resemblance to DNA sequences in rhesus monkeys that got transcribed into long noncoding RNAs (lncRNAs), which didn’t make proteins or have any other apparent purpose. Li couldn’t figure out what it had taken for those stretches of monkey DNA to become true protein-coding genes in humans. © 2023 American Association for the Advancement of Science.

Keyword: Development of the Brain; Genes & Behavior
Link ID: 28624 - Posted: 01.07.2023

By Jake Buehler Female snakes have clitorises too, a new study finds. The research raises the possibility that the sex lives of snakes are more complicated and diverse than previously understood, researchers report December 14 in Proceedings of the Royal Society B. Clitorises are found in a wide range of vertebrate life, from crocodiles to dolphins (SN: 1/10/22). One exception is birds, which lost their clitorises over the course of their evolution. Female snakes appeared to have lost the sex organ too, which was puzzling, since their close lizard relatives possess paired clitorises, called hemiclitorises. Male lizards and snakes have accompanying paired phalli, or hemipenises.  This element of female snakes’ sexual anatomy went unexamined in detail for so long partly because hemiclitorises can be fragile and easy to miss, but also because female genitalia have historically been considered “quite taboo,” says evolutionary biologist Megan Folwell of the University of Adelaide in Australia. “Even in humans, the proper function and significance of the human clitoris was still being discussed in 2006,” she says. Conflicting accounts of snake hemiclitorises in some scientific papers led Folwell to take a detailed look. She first examined a euthanized female common death adder (Acanthophis antarcticus). “I just started with dissecting the tail and going into it with a really open mind of what I might find,” she says. She was “pleasantly surprised” to find dual organs within that were completely different from the hemipenises found in male snakes. Also, unlike lizard hemiclitorises, the snake’s couldn’t turn out externally. © Society for Science & the Public 2000–2022.

Keyword: Sexual Behavior; Evolution
Link ID: 28594 - Posted: 12.15.2022

By Emily Anthes In creating modern dog breeds, humans sculpted canines into physical specimens perfectly suited for a wide variety of tasks. Bernese mountain dogs have solid, muscular bodies capable of pulling heavy loads, while greyhounds have lean, aerodynamic frames, ideal for chasing down deer. The compact Jack Russell terrier can easily shimmy into fox or badger dens. Now, a large study, published in Cell on Thursday, suggests that behavior, not just appearance, has helped qualify these dogs for their jobs. Breeds that were created for similar roles — whether rounding up sheep or flushing birds into the air — tend to cluster into distinct genetic lineages, which can be characterized by different combinations of behavioral tendencies, the researchers found. “Much of modern breeding has been focused predominantly on what dogs look like,” Evan MacLean, an expert on canine cognition at the University of Arizona who was not involved in the study, said in an email. But, he emphasized, “Long before we were breeding dogs for their appearances, we were breeding them for behavioral traits.” The study also found that many of the genetic variants that set these lineages apart from each other appear to regulate brain development, and many seem to predate modern breeds. Together, the results suggest that people may have created today’s stunning assortment of breeds, in part, by harnessing and preserving desirable behavioral traits that already existed in ancient dogs, the researchers said. “Dogs have fundamentally the same blueprint, but now you’ve got to emphasize certain things to get particular tasks done,” said Elaine Ostrander, a dog genomics expert at the National Human Genome Research Institute and the senior author of the study. “You’re going to tweak a gene up, you’re going to tweak it down.” In an email, Bridgett vonHoldt, an evolutionary biologist at Princeton University who was not involved in the research, called the new paper “a major landmark in the field of dog genomics and behavior. We know it is complicated. This study not only gives us hope, it will be viewed as an inspiration for all in the field.” © 2022 The New York Times Company

Keyword: Genes & Behavior; Evolution
Link ID: 28589 - Posted: 12.10.2022

By Bruce Bower An ancient hominid dubbed Homo naledi may have lit controlled fires in the pitch-dark chambers of an underground cave system, new discoveries hint. Researchers have found remnants of small fireplaces and sooty wall and ceiling smudges in passages and chambers throughout South Africa’s Rising Star cave complex, paleoanthropologist Lee Berger announced in a December 1 lecture hosted by the Carnegie Institution of Science in Washington, D.C. “Signs of fire use are everywhere in this cave system,” said Berger, of the University of the Witwatersrand, Johannesburg. H. naledi presumably lit the blazes in the caves since remains of no other hominids have turned up there, the team says. But the researchers have yet to date the age of the fire remains. And researchers outside Berger’s group have yet to evaluate the new finds. H. naledi fossils date to between 335,000 and 236,000 years ago (SN: 5/9/17), around the time Homo sapiens originated (SN: 6/7/17). Many researchers suspect that regular use of fire by hominids for light, warmth and cooking began roughly 400,000 years ago (SN: 4/2/12). Such behavior has not been attributed to H. naledi before, largely because of its small brain. But it’s now clear that a brain roughly one-third the size of human brains today still enabled H. naledi to achieve control of fire, Berger contends. Last August, Berger climbed down a narrow shaft and examined two underground chambers where H. naledi fossils had been found. He noticed stalactites and thin rock sheets that had partly grown over older ceiling surfaces. Those surfaces displayed blackened, burned areas and were also dotted by what appeared to be soot particles, Berger said. © Society for Science & the Public 2000–2022.

Keyword: Evolution
Link ID: 28582 - Posted: 12.06.2022

Cephalopods like octopuses, squids and cuttlefish are highly intelligent animals with complex nervous systems. In “Science Advances”, a team led by Nikolaus Rajewsky of the Max Delbrück Center has now shown that their evolution is linked to a dramatic expansion of their microRNA repertoire. If we go far enough back in evolutionary history, we encounter the last known common ancestor of humans and cephalopods: a primitive wormlike animal with minimal intelligence and simple eyespots. Later, the animal kingdom can be divided into two groups of organisms – those with backbones and those without. While vertebrates, particularly primates and other mammals, went on to develop large and complex brains with diverse cognitive abilities, invertebrates did not. With one exception: the cephalopods. Scientists have long wondered why such a complex nervous system was only able to develop in these mollusks. Now, an international team led by researchers from the Max Delbrück Center and Dartmouth College in the United States has put forth a possible reason. In a paper published in “Science Advances”, they explain that octopuses possess a massively expanded repertoire of microRNAs (miRNAs) in their neural tissue – reflecting similar developments that occurred in vertebrates. “So, this is what connects us to the octopus!” says Professor Nikolaus Rajewsky, Scientific Director of the Berlin Institute for Medical Systems Biology of the Max Delbrück Center (MDC-BIMSB), head of the Systems Biology of Gene Regulatory Elements Lab, and the paper’s last author. He explains that this finding probably means miRNAs play a fundamental role in the development of complex brains.

Keyword: Evolution; Epigenetics
Link ID: 28571 - Posted: 11.30.2022

By Diana Kwon Crows are some of the smartest creatures in the animal kingdom. They are capable of making rule-guided decisions and of creating and using tools. They also appear to show an innate sense of what numbers are. Researchers now report that these clever birds are able to understand recursion—the process of embedding structures in other, similar structures—which was long thought to be a uniquely human ability. Recursion is a key feature of language. It enables us to build elaborate sentences from simple ones. Take the sentence “The mouse the cat chased ran.” Here the clause “the cat chased” is enclosed within the clause “the mouse ran.” For decades, psychologists thought that recursion was a trait of humans alone. Some considered it the key feature that set human language apart from other forms of communication between animals. But questions about that assumption persisted. “There’s always been interest in whether or not nonhuman animals can also grasp recursive sequences,” says Diana Liao, a postdoctoral researcher at the lab of Andreas Nieder, a professor of animal physiology at the University of Tübingen in Germany. In a study of monkeys and human adults and children published in 2020, a group of researchers reported that the ability to produce recursive sequences may not actually be unique to our species after all. Both humans and monkeys were shown a display with two pairs of bracket symbols that appeared in a random order. The subjects were trained to touch them in the order of a “center-embedded” recursive sequence such as { ( ) } or ( { } ). After giving the right answer, humans received verbal feedback, and monkeys were given a small amount of food or juice as a reward. Afterward the researchers presented their subjects with a completely new set of brackets and observed how often they arranged them in a recursive manner. Two of the three monkeys in the experiment generated recursive sequences more often than nonrecursive sequences such as { ( } ), although they needed an additional training session to do so. One of the animals generated recursive sequences in around half of the trials. Three- to four-year-old children, by comparison, formed recursive sequences in approximately 40 percent of the trials. © 2022 Scientific American,

Keyword: Evolution; Learning & Memory
Link ID: 28563 - Posted: 11.23.2022

By Alejandro Portilla Navarro Dawn breaks in San Jose, the capital of Costa Rica. The city is still asleep, but the early risers are greeted by a beautiful symphony: Hummingbirds, corn-eaters, yigüirros (clay-colored thrushes), yellow-breasted grosbeaks, blue tanagers, house wrens, warblers and other birds announce that a new day has arrived. Soon the incessant noise of vehicles and their horns, construction, street vendors and more take over, shaping the soundscape of the frenetic routine of hundreds of thousands of people who travel and live in this city. Then, the birds’ songs will slip into the background. “The act of birdsong has two main functions in males: It is to attract females and also to defend their territory from other males,” says Luis Andrés Sandoval Vargas, an ornithologist at the University of Costa Rica. For females in the tropics, he adds, the primary role of their song is to defend territory. Thus, in order to communicate in cities, to keep their territory safe and find mates, birds must find ways to counteract the effects of anthropogenic noise — that is, the noise produced by humans. “The main effect of urban development on song is that many birds sing at higher frequencies,” says Sandoval Vargas. Studies over the past 15 years have found, for example, that blackbirds (Turdus merula), great tits (Parus major) and rufous-collared sparrows (Zonotrichia capensis) sing at higher pitches, with higher minimum frequencies, in urban environments than in rural ones. But the birds’ response to anthropogenic noise may be more complex than that, as Sandoval Vargas found when studying house wrens (Troglodytes aedon). House wrens are small, brown birds — about 10 centimeters tall and weighing 12 grams — that feed on insects and tend to live near humans. In Costa Rica, they are found almost everywhere, but are especially abundant in the cities. “Males sing almost year-round and sing for many hours during the day, and much of their behavior is mediated by vocalizations,” explains Sandoval Vargas. But what makes them ideal for studying adaptations to urban environments is that most of the components of their song are within the same frequency range as the noise that we humans produce. © 2022 Annual Reviews

Keyword: Animal Communication; Evolution
Link ID: 28553 - Posted: 11.16.2022

Emma Marris For the first time, octopuses have been spotted throwing things — at each other1. Octopuses are known for their solitary nature, but in Jervis Bay, Australia, the gloomy octopus (Octopus tetricus) lives at very high densities. A team of cephalopod researchers decided to film the creatures with underwater cameras to see whether — and how — they interact. Once the researchers pulled the cameras out of the water, they sat down to watch more than 20 hours of footage. “I call it octopus TV,” laughs co-author David Scheel, a behavioural ecologist at Alaska Pacific University in Anchorage. One behaviour stood out: instances in which the eight-limbed creatures gathered shells, silt or algae with their arms — and then hurled them away, propelling them with water jetted from their siphon. And although some of the time it seemed that they were just throwing away debris or food leftovers, it did sometimes appear that they were throwing things at each other. The team found clues that the octopuses were deliberately targeting one another. Throws that made contact with another octopus were relatively strong and often occurred when the thrower was displaying a uniform dark or medium body colour. Another clue: sometimes the octopuses on the receiving end ducked. Throws that made octo-contact were also more likely to be accomplished with a specific set of arms, and the projectile was more likely to be silt. “We weren’t able to try and assess what the reasons might be,” Scheel cautions. But throwing, he says, “might help these animals deal with the fact that there are so many octopuses around”. In other words, it is probably social. © 2022 Springer Nature Limited

Keyword: Evolution; Learning & Memory
Link ID: 28549 - Posted: 11.13.2022

Laurel Wamsley Perhaps the real law of the jungle is that it's good to have friends — especially those who know where to find the the free food. Case in point: It turns out chimpanzees and gorillas can be pals, evidently with advantages for all. That finding is from a new paper in the journal iScience that analyzes social interactions between the primate species over two decades at the Nouabalé-Ndoki Park in the Republic of Congo. Over that 20-year period, researchers saw gorillas follow the sound of chimps to a canopy full of ripe figs, and then co-feed at the same tree. They witnessed young individuals of both species playing and wrestling with each other – interactions that can foster their development. And when bands of the two species encountered each other, researchers saw gorillas and chimps scan the others and then approach the ones they knew. They even saw chimpanzees beating their chests – a behavior associated with gorillas. Researchers had theorized that associations between the species could perhaps be to avoid predators such as leopards or snakes. But the apes' behavior didn't show that to be a major factor in their interactions. "Predation is certainly a threat in this region, as we have cases in which chimpanzees have been killed by leopards," Washington University primatologist Crickette Sanz, who led the research, said in a news release. "However, the number of chimpanzees in daily subgroups remains relatively small, and gorillas within groups venture far from the silverback who is thought to be a protector from predation." Instead, better foraging seemed to be a key upside for both species – sometimes eating at the same tree, sometimes dining nearby on different foods. Not every interaction was warm and friendly. "Interspecific aggression was bidirectional and most frequently consisted of threats," the study notes – but it never rose to the level of lethal aggression that has occurred between chimps and gorillas in Gabon. © 2022 npr

Keyword: Evolution; Learning & Memory
Link ID: 28548 - Posted: 11.13.2022

Vanessa Rom When put to the test, bees have proved over and over again that they've got a lot more to offer than pollinating, making honey and being fiercely loyal to a queen. The industrious insects can count and alter their behavior when things seem difficult, and now some scientists say there's proof they also like to play. A study recently published in Animal Behavior suggests that bumblebees, when given the chance, like to fool around with toys. Researchers from Queen Mary University of London conducted an experiment in which they set up a container that allowed bees to travel from their nest to a feeding area. But along the way, the bees could opt to pass through a separate section with a smattering of small wooden balls. Over 18 days, the scientists watched as the bees "went out of their way to roll wooden balls repeatedly, despite no apparent incentive to do so." The finding suggests that like humans, insects also interact with inanimate objects as a form of play. Also similar to people, younger bees seemed to be more playful than adult bees. In this experiment from researchers at Queen Mary University of London, bumblebees, especially young ones, appeared to show they liked to cling to wooden balls twice their size and roll them around just for the fun of it. "This research provides a strong indication that insect minds are far more sophisticated than we might imagine," Lars Chittka, a professor of sensory and behavioral ecology at Queen Mary University of London, who led the study, said in a statement. Earlier studies have shown that the black and yellow bugs are willing to learn new tricks in exchange for food or other rewards, so in this case Chittka and his team set out to create conditions that would eliminate external variables. They made sure that the bees had acclimated to their new home and that their environment was stress free. © 2022 npr

Keyword: Emotions; Evolution
Link ID: 28538 - Posted: 11.05.2022

By Jack Tamisiea An elephant’s trunk has 40,000 muscles and weighs more than a Burmese python. The appendage is strong enough to uproot a tree, yet sensitive enough to suction up fragile tortilla chips. But how does an elephant’s brain help accomplish these feats of dexterity? That has been difficult to study, according to Michael Brecht, a neuroscientist at the Humboldt University of Berlin. Weighing in excess of 10 pounds, the elephant’s brain degrades quickly after death and is a hassle to store. “I tend to think that the big animals are a bit neglected because we don’t do enough work on big brains,” Dr. Brecht said. Dr. Brecht and his colleagues were fortunate enough to gain access to a trove of elephant brains from animals that had died of natural causes or were euthanized for health reasons and ended up either frozen or in a fixative substance at the Leibniz Institute for Zoo and Wildlife Research in Berlin. In a study published Wednesday in the journal Science Advances, Dr. Brecht and his colleagues reported that elephants had more facial neurons than any other land mammal, which might contribute to trunk dexterity and other anatomical abilities. The study also helped to pinpoint major differences between the neural wirings of African savanna elephants and Asian elephants. Using the brains of four Asian elephants and four African savanna elephants, the researchers homed in on the facial nucleus, a bundle of neurons concentrated in the brainstem and hooked up to facial nerves. In mammals, these neurons serve as the control center for facial muscles. They’re in command whenever you wrinkle your nose, purse your lips or raise your eyebrows. They also help elephants employ their trunks. The researchers divided the facial nucleus into regions of neurons that controlled the elephant’s ears, lips and trunk. African elephants sported 63,000 facial neurons, while their Asian cousins had 54,000. The only mammals with more are dolphins, which pack nearly 90,000 facial neurons into their sensitive snouts. While his team expected both African savanna and Asian elephants to possess massive stores of facial neurons, Dr. Brecht said the discrepancy between the two species was noteworthy. © 2022 The New York Times Company

Keyword: Evolution; Pain & Touch
Link ID: 28533 - Posted: 10.28.2022

Elizabeth Pennisi Think of the chattiest creatures in the animal kingdom and songbirds, dolphins, and—yes—humans probably come to mind. Turtles probably don’t register. But these charismatic reptiles also communicate using a large repertoire of clicks, snorts, and chortles. Now, by recording the “voices” of turtles and other supposedly quiet animals, scientists have concluded that all land vertebrate vocalizations—from the canary’s song to the lion’s roar—have a common root that dates back more than 400 million years. The findings imply animals began to vocalize very early in their evolutionary history—even before they possessed well-developed ears, says W. Tecumseh Fitch, a bioacoustician at the University of Vienna who was not involved with the work. “It suggests our ears evolved to hear these vocalizations.” Several years ago, University of Arizona evolutionary ecologist John Wiens and his graduate student Zhuo Chen started looking into the evolutionary roots of acoustic communication—basically defined as the sounds animals make with their mouths using their lungs. Combing the scientific literature, the duo compiled a family tree of all the acoustic animals known at the time, eventually concluding such soundmaking abilities arose multiple times in vertebrates between 100 million and 200 million years ago. But Gabriel Jorgewich-Cohen, an evolutionary biologist at the University of Zürich, noticed an oversight: turtles. Though Wiens and Chen had found that only two of 14 families of turtles made sounds, he was finding a lot more. He spent 2 years recording 50 turtle species in the act of “speaking.”

Keyword: Hearing; Evolution
Link ID: 28530 - Posted: 10.28.2022

By Hannah Thomasy Ned and Sunny stretch out together on the warm sand. He rests his head on her back, and every so often he might give her an affectionate nudge with his nose. The pair is quiet and, like many long-term couples, they seem perfectly content just to be in each other’s presence. The couple are monogamous, which is quite rare in the animal kingdom. But Sunny and Ned are a bit scalier that your typical lifelong mates — they are shingleback lizards that live at Melbourne Museum in Australia. In the wild, shinglebacks regularly form long-term bonds, returning to the same partner during mating season year after year. One lizard couple in a long-term study had been pairing up for 27 years and were still going strong when the study ended. In this way, the reptiles are more like some of the animal kingdom’s most famous long-term couplers, such as albatrosses, prairie voles and owl monkeys, and they confound expectations many people have about the personalities of lizards. “There’s more socially going on with reptiles than we give them credit for,” said Sean Doody, a conservation biologist at the University of South Florida. Social behavior in reptiles has been largely overlooked for decades, but a handful of dedicated scientists have begun unraveling reptiles’ cryptic social structures. With the help of camera traps and genetic testing, scientists have discovered reptiles living in family groups, caring for their young and communicating with each other in covert ways. And they aren’t only doing this because they love lizards. Currently, one in five reptile species are threatened with extinction; researchers say learning more about reptile sociality could be crucial for conservation. Humans have a long history of animosity toward reptiles, and influential twentieth century scientists added to the idea of reptiles as cold, unintelligent beasts. In the mid-1900s, Paul MacLean, a neuroscientist at Yale and then the National Institute of Mental Health, began developing the triune brain hypothesis. He theorized that the human brain contained three parts: the reptilian R-complex, which governed survival and basic instinctual behaviors; the paleomammalian complex, which controlled emotional behavior; and the neomammalian cortex, which was responsible for higher functions like problem-solving and language. © 2022 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 28528 - Posted: 10.26.2022

By David Grimm “Whooo’s a good boy?” “Whooo’s a pretty kitty?” When it comes to communicating with our pets, most of us can’t help but talk to them like babies. We pitch our voices high, extend our vowels, and ask short, repetitive questions. Dogs seem to like this. They’re far more likely to pay attention to us when we use this “caregiver speech,” research has shown. Now, scientists have found the same is true for cats, though only when their owner is talking. The work adds evidence that cats—like dogs—may bond with us in some of the same ways infants do. “It’s a fascinating study,” says Kristyn Vitale, an animal behaviorist and expert on cat cognition at Unity College, who was not involved with the work. “It further supports the idea that our cats are always listening to us.” Charlotte de Mouzon had a practical reason for getting into this line of research. An ethologist at Paris Nanterre University, she had previously been a cat behaviorist, consulting with owners on how to solve everything from litter box problems to aggressive behavior. “Sometimes people would ask me, ‘What’s the scientific evidence behind your approaches?’” she says. “I was frustrated that there were no studies being done on cat behavior in France.” So, she began a Ph.D. and was soon studying cat-human communication. As a first step, de Mouzon confirmed what most cat owners already know: We dip into “baby talk” when we address our feline friends–a habit de Mouzon is guilty of herself. “What’s up, my little ones?” she finds herself asking in a high-pitched voice when greeting her two kitties, Mila and Shere Khan. But do cats, like dogs, actually respond more to this “cat-directed speech”? To find out, de Mouzon recruited 16 cats and their owners—students at the Alfort National Veterinary School just outside of Paris. Because cats can be challenging to work with, de Mouzon studied them on feline-friendly turf, converting a common room in the students’ dormitory into a makeshift animal behavior lab filled with toys, a litter box, and places to hide.

Keyword: Animal Communication; Language
Link ID: 28525 - Posted: 10.26.2022

Ewen Callaway Set on a rocky outcrop in southern Siberia, Chagyrskaya Cave might not look like much. But for one family of Neanderthals, it was home. For the first time, researchers have identified a set of closely related Neanderthals: a father and his teenage daughter and two other, more-distant relatives. The discovery of the family — reported on 19 October in Nature1 — and seven other individuals (including a pair of possible cousins from another clan) in the same cave, along with two more from a nearby site, represents the largest ever cache of Neanderthal genomes. The findings also suggest that Neanderthal communities were small, and that females routinely left their families to join new groups. Gleaning insights into kinship and social structure is new territory for ancient-genome studies, which have typically focused on broader population history, says Krishna Veeramah, a population geneticist at Stonybrook University in New York. “The fact that we can do this with Neanderthals is incredible.” Buried treasure Set on the banks of the Charysh River in the foothills of the Altai mountains, Chagyrskaya is 100 kilometres west of Denisova Cave, an archaeological treasure trove in which humans, Neanderthals, Denisovans (and at least one Neanderthal–Denisovan hybrid) all lived intermittently over some 300,000 years2,3. Excavations of Chagyrskaya, however, have so far revealed only Neanderthal remains, dated to between 50,000 to 60,000 years ago, and characteristic stone tools. In 2020, a genome sequence from a female Neanderthal from Chagyrskaya suggested she belonged to population distinct from those that occupied Denisova Cave much earlier4. To study the cave’s inhabitants in greater depth, a team of researchers led by palaeogeneticist Laurits Skov and population geneticist Benjamin Peter at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, extracted DNA from 17 other ancient-human remains from Chagyrskaya, as well as several from a nearby cave, called Okladnikov. © 2022 Springer Nature Limited

Keyword: Evolution
Link ID: 28521 - Posted: 10.22.2022

By Benjamin Mueller Svante Pääbo, a Swedish scientist who peered back into human history by retrieving genetic material from 40,000-year-old bones, producing a complete Neanderthal genome and launching the field of ancient DNA studies, was awarded the Nobel Prize in Physiology or Medicine on Monday. The prize recognized an improbable scientific career. Having once dreamed of becoming an Egyptologist, Dr. Pääbo devoted his early years of research to extracting genetic material from mummies, only for that research to run aground because the samples might have become contaminated by his and his colleagues’ own DNA. Within about two decades, in 2006, he had launched an unlikely effort to decipher a Neanderthal genome. He designed so-called clean rooms dedicated to handling ancient DNA, which protected his fossils from the genetic material of living humans. And dramatic advances in sequencing technology allowed him to decode the sort of badly damaged DNA found in ancient bones. “It was certainly considered to be impossible to recover DNA from 40,000-year-old bones,” said Dr. Nils-Göran Larsson, the chairman of the Nobel Committee for Physiology or Medicine and a professor of medical biochemistry at the Karolinska Institute in Stockholm. In 2010, Dr. Pääbo unveiled the Neanderthal genome. The publication opened a window into questions about what made early humans different from modern ones. It also helped scientists track genetic differences in modern humans and understand what role those differences play in disease, including Covid-19. In 2020, Dr. Pääbo and a colleague found that the coronavirus caused more severe symptoms in people who had inherited a stretch of Neanderthal DNA. Even some of Dr. Pääbo’s biggest admirers described the prize as unexpected. Analysts have long speculated that the scientists who sequenced the modern human genome were strong contenders for a Nobel Prize, not thinking that the scientist who sequenced Neanderthal DNA would get there first. But geneticists said that the two projects were interwoven: Rapid advances in sequencing technology that followed the beginning of the Human Genome Project in 1990, they said, helped Dr. Pääbo to interpret tiny quantities of Neanderthal DNA, damaged as they were from tens of thousands of years underground. © 2022 The New York Times Company

Keyword: Evolution; Genes & Behavior
Link ID: 28500 - Posted: 10.05.2022

By Tess Joosse “Bird brain” insults be damned. The noggins of our flying friends are packed with neurons, and recent studies have shown birds can develop complex tools and even discriminate between paintings by Claude Monet and Pablo Picasso. But is this avian acumen a recent development, evolutionarily speaking, or does it trace back tens of millions of years? A remarkably preserved fossil unearthed in Brazil may hold some answers. The 80-million-year-old bird skull contains impressions of advanced brain structures, suggesting early birds were bright like modern ones. The preserved braincase, from a now-extinct bird lineage, is “exceptional … a big step forward,” says Matteo Fabbri, an evolutionary biologist at the Field Museum of Natural History who was not involved with the work. “This is the first time we have really good information regarding the brain of [this] group.” Birds began to evolve about 165 million to 150 million years ago from dinosaurs. Some of the earliest—whose ancestors were carnivorous icons such as Velociraptor—were the famous feathered Archaeopteryx. Over time, avians branched into a group called the enantiornithines and close cousins who became modern birds. Ranging from the size of hummingbirds to turkeys, enantiornithines took to the skies in the Mesozoic era beginning 130 million years ago. The creatures eventually spanned the globe before going extinct 66 million years ago from the same asteroid impact that killed off the dinosaurs. Their position between Archaeopteryx and living birds gives them a “magical place on the dino-bird family tree,” says Daniel Field, a paleontologist at the University of Cambridge and co-author of the new study. To reconstruct the brains of ancient birds, researchers need fossils that preserve the hollow space where a brain would sit: the braincase. But no enantiornithine skeletons have preserved that space—until the new find. © 2022 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 28492 - Posted: 09.28.2022

By Darren Incorvaia Songbirds get a lot of love for their dulcet tones, but drummers may start to steal some of that spotlight. Woodpeckers, which don’t sing but do drum on trees, have brain regions that are similar to those of songbirds, researchers report September 20 in PLOS Biology. The finding is surprising because songbirds use these regions to learn their songs at an early age, yet it’s not clear if woodpeckers learn their drum beats (SN: 9/16/21). Whether woodpeckers do or not, the result suggests a shared evolutionary origin for both singing and drumming. The ability to learn vocalizations by listening to them, just like humans do when learning to speak, is a rare trait in the animal kingdom. Vocal learners, such as songbirds, hummingbirds and parrots, have independently evolved certain clusters of nerve cells called nuclei in their forebrains that control the ability. Animals that don’t learn vocally are thought to lack these brain features. While it’s commonly assumed that other birds don’t have these nuclei, “there’s thousands of birds in the world,” says Matthew Fuxjager, a biologist at Brown University in Providence, R.I. “While we say these brain regions only exist in these small groups of species, nobody’s really looked in a lot of these other taxa.” Fuxjager and his colleagues examined the noggins of several birds that don’t learn vocally to check if they really did lack these brain nuclei. Using molecular probes, the team checked the bird brains for activity of a gene called parvalbumin, a known marker of the vocal learning nuclei. Many of the birds, including penguins and flamingos, came up short, but there was one exception — male and female woodpeckers, which had three spots in their brains with high parvalbumin activity. © Society for Science & the Public 2000–2022.

Keyword: Animal Communication; Language
Link ID: 28486 - Posted: 09.21.2022