Chapter 6. Evolution of the Brain and Behavior

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By Bruce Bower A child’s partial skull found in a remote section of a South African cave system has fueled suspicion that an ancient hominid known as Homo naledi deliberately disposed of its dead in caves. An international team led by paleoanthropologist Lee Berger of University of the Witwatersrand, Johannesburg pieced together 28 skull fragments and six teeth from a child’s skull discovered in a narrow opening located about 12 meters from an underground chamber where cave explorers first found H. naledi fossils (SN: 9/10/15). Features of the child’s skull qualify it as H. naledi, a species with an orange-sized brain and skeletal characteristics of both present-day people and Homo species from around 2 million years ago. “The case is building for deliberate, ritualized body disposal in caves by Homo naledi,” Berger said at a November 4 news conference held in Johannesburg. While that argument is controversial, there is no evidence that the child’s skull was washed into the tiny space or dragged there by predators or scavengers (SN: 4/19/16). Berger’s group describes the find in two papers published November 4 in PaleoAnthropology. In one, Juliet Brophy, a paleoanthropologist at Louisiana State University in Baton Rouge and colleagues describe the youngster’s skull. In the other, paleoanthropologist Marina Elliott of Canada’s Simon Fraser University in Burnaby and colleagues detail new explorations in South Africa’s Rising Star cave system. © Society for Science & the Public 2000–2021.

Keyword: Evolution
Link ID: 28068 - Posted: 11.09.2021

By Laura Sanders Brains are like sponges, slurping up new information. But sponges may also be a little bit like brains. Sponges, which are humans’ very distant evolutionary relatives, don’t have nervous systems. But a detailed analysis of sponge cells turns up what might just be an echo of our own brains: cells called neuroids that crawl around the animal’s digestive chambers and send out messages, researchers report in the Nov. 5 Science. The finding not only gives clues about the early evolution of more complicated nervous systems, but also raises many questions, says evolutionary biologist Thibaut Brunet of the Pasteur Institute in Paris, who wasn’t involved in the study. “This is just the beginning,” he says. “There’s a lot more to explore.” The cells were lurking in Spongilla lacustris, a freshwater sponge that grows in lakes in the Northern Hemisphere. “We jokingly call it the Godzilla of sponges” because of the rhyme with Spongilla, say Jacob Musser, an evolutionary biologist in Detlev Arendt’s group at the European Molecular Biology Laboratory in Heidelberg, Germany. Simple as they are, these sponges have a surprising amount of complexity, says Musser, who helped pry the sponges off a metal ferry dock using paint scrapers. “They’re such fascinating creatures.” © Society for Science & the Public 2000–2021.

Keyword: Evolution; Development of the Brain
Link ID: 28065 - Posted: 11.06.2021

By Elizabeth Pennisi Dive among the kelp forests of the Southern California coast and you may spot orange puffball sponges (Tethya californiana)—creatures that look like the miniature pumpkins used for pies. No researchers paid them much mind until 2017, when William Joiner, a neuroscientist at the University of California (UC), San Diego, decided to look into whether sponges take naps. That’s not as silly a question as it seems. Over the past few years, studies in worms, jellyfish, and hydra have challenged the long-standing idea that sleep is unique to creatures with brains. Now, “The real frontier is finding an animal that sleeps that doesn’t have neurons at all,” says David Raizen, a neurologist at the University of Pennsylvania (UPenn) Perelman School of Medicine. Sponges, some of the earliest animals to appear on Earth, fit that description. To catch one snoozing could upend researchers’ definition of sleep and their understanding of its purpose. Scientists have often defined sleep as temporary loss of consciousness, orchestrated by the brain and for the brain’s benefit. That makes studying sleep in brainless creatures controversial. “I do not believe that many of these organisms sleep—at least not the way you and I do,” says John Hogenesch, a genome biologist at Cincinnati Children’s Hospital Medical Center. Calling the restful, unresponsive state seen in jellyfish and hydra “sleeplike” is more acceptable to him. But others in the field are pushing for a much more inclusive view: that sleep evolved not with modern vertebrates as previously assumed, but perhaps a half-billion years ago when the first animals appeared. “I think if it’s alive, it sleeps,” says Paul Shaw, a neuroscientist from Washington University in St. Louis. The earliest life forms were unresponsive until they evolved ways to react to their environment, he suggests, and sleep is a return to the default state. “I think we didn’t evolve sleep, we evolved wakefulness.” © 2021 American Association for the Advancement of Science.

Keyword: Sleep; Evolution
Link ID: 28061 - Posted: 11.03.2021

By Emily Anthes The brain of a fruit fly is the size of a poppy seed and about as easy to overlook. “Most people, I think, don’t even think of the fly as having a brain,” said Vivek Jayaraman, a neuroscientist at the Janelia Research Campus of the Howard Hughes Medical Institute in Virginia. “But, of course, flies lead quite rich lives.” Flies are capable of sophisticated behaviors, including navigating diverse landscapes, tussling with rivals and serenading potential mates. And their speck-size brains are tremendously complex, containing some 100,000 neurons and tens of millions of connections, or synapses, between them. Since 2014, a team of scientists at Janelia, in collaboration with researchers at Google, have been mapping these neurons and synapses in an effort to create a comprehensive wiring diagram, also known as a connectome, of the fruit fly brain. The work, which is continuing, is time-consuming and expensive, even with the help of state-of-the-art machine-learning algorithms. But the data they have released so far is stunning in its detail, composing an atlas of tens of thousands of gnarled neurons in many crucial areas of the fly brain. And now, in an enormous new paper, being published on Tuesday in the journal eLife, neuroscientists are beginning to show what they can do with it. By analyzing the connectome of just a small part of the fly brain — the central complex, which plays an important role in navigation — Dr. Jayaraman and his colleagues identified dozens of new neuron types and pinpointed neural circuits that appear to help flies make their way through the world. The work could ultimately help provide insight into how all kinds of animal brains, including our own, process a flood of sensory information and translate it into appropriate action. © 2021 The New York Times Company

Keyword: Brain imaging; Evolution
Link ID: 28057 - Posted: 10.30.2021

By Emily Anthes The brain of a fruit fly is the size of a poppy seed and about as easy to overlook. “Most people, I think, don’t even think of the fly as having a brain,” said Vivek Jayaraman, a neuroscientist at the Janelia Research Campus of the Howard Hughes Medical Institute in Virginia. “But, of course, flies lead quite rich lives.” Flies are capable of sophisticated behaviors, including navigating diverse landscapes, tussling with rivals and serenading potential mates. And their speck-size brains are tremendously complex, containing some 100,000 neurons and tens of millions of connections, or synapses, between them. Since 2014, a team of scientists at Janelia, in collaboration with researchers at Google, have been mapping these neurons and synapses in an effort to create a comprehensive wiring diagram, also known as a connectome, of the fruit fly brain. The work, which is continuing, is time-consuming and expensive, even with the help of state-of-the-art machine-learning algorithms. But the data they have released so far is stunning in its detail, composing an atlas of tens of thousands of gnarled neurons in many crucial areas of the fly brain. And now, in an enormous new paper, being published on Tuesday in the journal eLife, neuroscientists are beginning to show what they can do with it. By analyzing the connectome of just a small part of the fly brain — the central complex, which plays an important role in navigation — Dr. Jayaraman and his colleagues identified dozens of new neuron types and pinpointed neural circuits that appear to help flies make their way through the world. The work could ultimately help provide insight into how all kinds of animal brains, including our own, process a flood of sensory information and translate it into appropriate action. It is also a proof of principle for the young field of modern connectomics, which was built on the promise that constructing detailed diagrams of the brain’s wiring would pay scientific dividends. “It’s really extraordinary,” Dr. Clay Reid, a senior investigator at the Allen Institute for Brain Science in Seattle, said of the new paper. “I think anyone who looks at it will say connectomics is a tool that we need in neuroscience — full stop.” © 2021 The New York Times Company

Keyword: Brain imaging; Evolution
Link ID: 28055 - Posted: 10.27.2021

Nicola Davis They have fluffy ears, a penetrating stare and a penchant for monogamy. But it turns out that indris – a large, critically endangered species of lemur – have an even more fascinating trait: an unexpected sense of rhythm. Indri indri are known for their distinctive singing, a sound not unlike a set of bagpipes being stepped on. The creatures often strike up a song with members of their family either in duets or choruses, featuring sounds from roars to wails. Now scientists say they have analysed the songs of 39 indris living in the rainforest of Madagascar, revealing that – like humans – the creatures employ what are known as categorical rhythms. These rhythms are essentially distinctive and predictable patterns of intervals between the onset of notes. For example in a 1:1 rhythm, all the intervals are of equal length, while a 1:2 rhythm has some twice as long as those before or after – like the opening bars of We Will Rock You by Queen. “They are quite predictable [patterns], because the next note is going to come either one unit or two whole units after the previous note,” said Dr Andrea Ravignani, co-author of the research from the Max Planck Institute for Psycholinguistics. While the 1:1 rhythms have previously been identified in certain songbirds, the team say their results are the first time categorical rhythms have been identified in a non-human mammal. “The evidence is even stronger than in birds,” said Ravignani. © 2021 Guardian News & Media Limited

Keyword: Animal Communication; Language
Link ID: 28050 - Posted: 10.27.2021

Abby Olena Most people enjoy umami flavor, which is perceived when a taste receptor called T1R1/T1R3 senses the amino acid glutamate. In some other mammals, such as mice, however, this same receptor is much less sensitive to glutamate. In a new study published August 26 in Current Biology, researchers uncover the molecular basis for this difference. They show that the receptor evolved in humans and some other primates away from mostly binding free nucleotides, which are common in insects, to preferentially binding glutamate, which is abundant in leaves. The authors argue that the change facilitated a major evolutionary shift in these primates toward a plant-heavy diet. “The question always comes up about the evolution of umami taste: In humans, our receptor is narrowly tuned to glutamate, and we never had a good answer for why,” says Maude Baldwin, a sensory biologist at the Max Planck Institute for Ornithology in Germany. She was not involved in the new work, but coauthored a 2014 study with Yasuka Toda, who is also a coauthor on the new paper, showing that the T1R1/T1R3 receptor is responsible for sweet taste in hummingbirds. In the new study, the authors find “that this narrow tuning has evolved convergently multiple times [and] that it’s related to folivory,” she says, calling the paper “a hallmark, fantastic study, and one that will become a textbook example of how taste evolution can relate to diet and how to address these types of questions in a rigorous, comprehensive manner.” © 1986–2021 The Scientist.

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 28037 - Posted: 10.16.2021

By Trishla Ostwal Juan Negro crouched in the shadows just outside a cave, wearing his headlamp. For a brief moment, he wasn’t an ornithologist at the Spanish National Research Council’s Doñana Biological Station in Seville. He was a Neandertal, intent on catching dinner. As he waited in the cold, dark hours of the night, crowlike birds called choughs entered the cave. The “Neandertal” then stealthily snuck in and began the hunt. This idea to role-play started with butchered bird bones. Piles of ancient tool- and tooth-nicked choughs bones have been found in the same caves that Neandertals frequented, evidence suggesting that the ancient hominids chowed down on the birds. But catching choughs is tricky. During the day, they fly far to feed on invertebrates, seeds and fruits. At night though, their behavior practically turns them into sitting ducks. The birds roost in groups and often return to the same spot, even if they’ve been disturbed or preyed on there before. So the question was, how might Neandertals have managed to catch these avian prey? To find out, Negro and his colleagues decided to act like, well, Neandertals. Wielding bare hands along with butterfly nets and lamps — proxy for nets (SN: 04/09/20) and fire (SN: 2/20/14) that Neandertals may have had at hand— teams of two to 10 researchers silently snuck into caves and other spots across Spain, where the birds roost to see how many choughs they could catch. a person inside a building attempting to catch a bird © Society for Science & the Public 2000–2021

Keyword: Evolution
Link ID: 28026 - Posted: 10.09.2021

Linda Geddes Your dog might follow commands such as “sit”, or become uncontrollably excited at the mention of the word “walkies”, but when it comes to remembering the names of toys and other everyday items, most seem pretty absent-minded. Now a study of six “genius dogs” has advanced our understanding of dogs’ memories, suggesting some of them possess a remarkable grasp of the human language. Hungarian researchers spent more than two years scouring the globe for dogs who could recognise the names of their various toys. Although most can learn commands to some degree, learning the names of items appears to be a very different task, with most dogs unable to master this skill. Max (Hungary), Gaia (Brazil), Nalani (Netherlands), Squall (US), Whisky (Norway), and Rico (Spain) made the cut after proving they knew the names of more than 28 toys, with some knowing more than 100. They were then enlisted to take part in a series of livestreamed experiments known as the Genius Dog Challenge. “These gifted dogs can learn new names of toys in a remarkable speed,” said Dr Claudia Fugazza at Eötvös Loránd University in Budapest, who led the research team. “In our previous study we found that they could learn a new toy name after hearing it only four times. But, with such short exposure, they did not form a long-term memory of it.” To further push the dogs’ limits, their owners were tasked with teaching them the names of six, and then 12 new toys in a single week. © 2021 Guardian News & Media Limited

Keyword: Animal Communication; Language
Link ID: 28023 - Posted: 10.06.2021

By Sam Roberts Washoe was 10 months old when her foster parents began teaching her to talk, and five months later they were already trumpeting her success. Not only had she learned words; she could also string them together, creating expressions like “water birds” when she saw a pair of swans and “open flower” to gain admittance to a garden. Washoe was a chimpanzee. She had been born in West Africa, probably orphaned when her mother was killed, sold to a dealer, flown to the United States for use of testing by the Air Force and adopted by R. Allen Gardner and his wife, Beatrix. She was raised as if she were a human child. She craved oatmeal with onions and pumpkin pudding. “The object of our research was to learn how much chimps are like humans,” Professor Gardner told Nevada Today, a University of Nevada publication, in 2007. “To measure this accurately, chimps would be needed to be raised as human children, and to do that, we needed to share a common language.” Washoe ultimately learned some 200 words, becoming what researchers said was the first nonhuman to communicate using sign language developed for the deaf. Professor Gardner, an ethologist who, with his wife, raised the chimpanzee for nearly five years, died on Aug. 20 at his ranch near Reno, Nev. He was 91. His death was announced by the University of Nevada, Reno, where he had joined the faculty in 1963 and conducted his research until he retired in 2010. When scientific journals reported in 1967 that Washoe (pronounced WA-sho), named after a county in Nevada, had learned to recognize and use multiple gestures and expressions in sign language, the news electrified the world of psychologists and ethologists who study animal behavior. © 2021 The New York Times Company

Keyword: Language; Evolution
Link ID: 28013 - Posted: 10.02.2021

By Tara Ellison As menopause hit, I found I wasn’t as interested in intimacy as I used to be. Sex started to feel like a box that needed to be checked a couple of times a week, and that was causing problems in my marriage. But it wasn’t just sex. I felt was slowing down in many areas. After hot flashes in my 40s had sent me running to the gynecologist for help, I’d been using bioidentical creams to balance my declining hormones. When, at 51, I confided to a friend that I’d had limited success with what my doctor prescribed, she said that she was thriving on something called hormonal “pellets.” I grilled her about them and then made an appointment with her practitioner, an internal medicine doctor. He ordered extensive lab work, which showed that my testosterone levels were very low, which can happen with aging. The doctor said I had two options: do nothing, which he said would eventually likely lead to loss of muscle, decreased bone density and a host of other health complications. Or up my testosterone. Testosterone therapy for women is a hotly debated subject. Studies suggest that testosterone can heighten libido in women with hypoactive sexual desire disorder (HSDD), at least in the short term. A recent statement by a group of international medical societies involved with women’s health endorsed the use of testosterone therapy in women for HSDD, and specifically excluded pellets and injectables as “not recommended.” It also cautioned there was not enough data to support the use of testosterone therapy for cognitive performance.

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28009 - Posted: 09.29.2021

By Carl Zimmer Ancient human footprints preserved in the ground across the White Sands National Park in New Mexico are astonishingly old, scientists reported on Thursday, dating back about 23,000 years to the Ice Age. The results, if they hold up to scrutiny, would rejuvenate the scientific debate about how humans first spread across the Americas, implying that they did so at a time when massive glaciers covered much of their path. Researchers who have argued for such an early arrival hailed the new study as firm proof. “I think this is probably the biggest discovery about the peopling of America in a hundred years,” said Ciprian Ardelean, an archaeologist at Autonomous University of Zacatecas in Mexico who was not involved in the work. “I don’t know what gods they prayed to, but this is a dream find.” For decades, many archaeologists have maintained that humans spread across North and South America only at the end of the last ice age. They pointed to the oldest known tools, including spear tips, scrapers and needles, dating back about 13,000 years. The technology was known as Clovis, named for the town of Clovis, N.M., where some of these first instruments came to light. The age of the Clovis tools lined up neatly with the retreat of the glaciers. That alignment bolstered a scenario in which Siberian hunter-gatherers moved into Alaska during the Ice Age, where they lived for generations until ice-free corridors opened and allowed them to expand southward. But starting in the 1970s, some archaeologists began publishing older evidence of humanity’s presence in North America. Last year, Dr. Ardelean and his colleagues published a report of stone tools in a mountain cave in Mexico dating back 26,000 years. © 2021 The New York Times Company

Keyword: Evolution
Link ID: 28006 - Posted: 09.25.2021

By Jonathan Lambert Vampire bats may be bloodthirsty, but that doesn’t mean they can’t share a drink with friends. Fights can erupt among bats over gushing wounds bit into unsuspecting animals. But bats that have bonded while roosting often team up to drink blood away from home, researchers report September 23 in PLOS Biology. Vampire bats (Desmodus rotundus) can form long-term social bonds with each other through grooming, sharing regurgitated blood meals and generally hanging out together at the roost (SN: 10/31/19). But whether these friendships, which occur between both kin and nonkin, extend to the bats’ nightly hunting had been unclear. “They’re flying around out there, but we didn’t know if they were still interacting with each other,” says Gerald Carter, an evolutionary biologist at Ohio State University in Columbus. To find out, Carter and his colleague Simon Ripperger of the Museum für Naturkunde in Berlin, built on previous research that uncovered a colony’s social network using bat backpacks. Tiny computer sensors glued to 50 female bats in Tolé, Panama, continuously registered proximity to other sensors both within the roost and outside, revealing when bats met up while foraging. Two common vampire bats feed on a cow near La Chorrera, Panama. It can take 10 to 40 minutes for a bat to bite a small, diamond-shaped wound into an animal’s flesh, and fights can sometimes break out over access to wounds. But researchers found that bats who are friendly back at the roost likely feed together in the field, potentially saving time and energy. © Society for Science & the Public 2000–2021

Keyword: Evolution
Link ID: 28005 - Posted: 09.25.2021

By Kimberly Hickok Seahorses are some of the most dazzling fish in the sea. They’re also the only group of animals in which the males, not the females, go through pregnancy and give birth. Now, new research finds the male’s brood pouch—which can hold up to 1000 baby seahorses at a time—develops and functions like a human placenta. “Evolution is just mind boggling,” says Camilla Whittington, an evolutionary biologist at the University of Sydney who led the new work. The study is the first to thoroughly examine how males nurture their young brood while they’re still in the pouch, says Mari Kawaguchi, an evolutionary biologist at Sophia University in Tokyo. Kawaguchi, who has studied seahorses for some 2 decades, has long suspected pregnant seahorses develop something resembling a placenta. Now, at last, there’s proof. Male seahorses start their path toward fatherhood with a dance. They twirl together with their chosen female under the water, changing colors and linking tails as they pirouette around a shared holdfast. Next, they align the female’s ovipositor with the male’s pouch opening so the female can deposit her eggs. Once the deed is done, the male gently sways to settle the eggs. Ten days to 6 weeks later, depending on the species, the male spends hours in labor, pumping and thrusting to force hundreds of tiny babies out into the water. There, they drift until they are grown. As for dad, he is ready for another round of courtship within hours after birth. But during pregnancy, males have one goal: Provide the embryos with everything they need, from oxygen to nutrients to antibodies. “One of the biggest challenges that all pregnant parents have is getting oxygen to their embryos and carbon dioxide away from the embryos,” Whittington says. “That’s really what motivated our study–how do those baby seahorses actually breathe, if you will, inside the brood pouch?” © 2021 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Evolution
Link ID: 28004 - Posted: 09.25.2021

By Carl Zimmer 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. For half a billion years or so, our ancestors sprouted tails. As fish, they used their tails to swim through the Cambrian seas. Much later, when they evolved into primates, their tails helped them stay balanced as they raced from branch to branch through Eocene jungles. But then, roughly 25 million years ago, the tails disappeared. Charles Darwin first recognized this change in our ancient anatomy. But how and why it happened has remained a mystery. Now a team of scientists in New York say they have pinpointed the genetic mutation that may have erased our tails. When the scientists made this genetic tweak in mice, the animals didn’t grow tails, according to a new study that was posted online last week. This dramatic anatomical change had a profound impact on our evolution. Our ancestors’ tail muscles evolved into a hammock-like mesh across the pelvis. When the ancestors of humans stood up and walked on two legs a few million years ago, that muscular hammock was ready to support the weight of upright organs. Although it’s impossible to definitively prove that this mutation lopped off our ancestors’ tails, “it’s as close to a smoking gun as one could hope for,” said Cedric Feschotte, a geneticist at Cornell who was not involved in the study. Darwin shocked his Victorian audiences by claiming that we descended from primates with tails. He noted that while humans and apes lack a visible tail, they share a tiny set of vertebrae that extend beyond the pelvis — a structure known as the coccyx. “I cannot doubt that it is a rudimentary tail,” he wrote. © 2021 The New York Times Company

Keyword: Evolution; Genes & Behavior
Link ID: 28001 - Posted: 09.22.2021

Christie Wilcox If it walks like a duck and talks like a person, it’s probably a musk duck (Biziura lobata)—the only waterfowl species known that can learn sounds from other species. The Australian species’ facility for vocal learning had been mentioned anecdotally in the ornithological literature; now, a paper published September 6 in Philosophical Transactions of the Royal Society B reviews and discusses the evidence, which includes 34-year-old recordings made of a human-reared musk duck named Ripper engaging in an aggressive display while quacking “you bloody fool.” Ripper quacking "you bloody fool" while being provoked by a person separated from him by a fence The Scientist spoke with the lead author on the paper, Leiden University animal behavior researcher Carel ten Cate, to learn more about these unique ducks and what their unexpected ability reveals about the evolution of vocal learning. The Scientist: What is vocal learning? Carel ten Cate: Vocal learning, as it is used in this case, is that animals and humans, they learn their sounds from experience. So they learn from what they hear around them, which will usually be the parents, but it can also be other individuals. And if they don’t get that sort of exposure, then they will be unable to produce species-specific vocalizations, or in the human case, speech sounds and proper spoken language. © 1986–2021 The Scientist.

Keyword: Language; Evolution
Link ID: 27987 - Posted: 09.13.2021

Abby Olena Most people enjoy umami flavor, which is perceived when a taste receptor called T1R1/T1R3 senses the amino acid glutamate. In some other mammals, such as mice, however, this same receptor is much less sensitive to glutamate. In a new study published August 26 in Current Biology, researchers uncover the molecular basis for this difference. They show that the receptor evolved in humans and some other primates away from mostly binding free nucleotides, which are common in insects, to preferentially binding glutamate, which is abundant in leaves. The authors argue that the change facilitated a major evolutionary shift in these primates toward a plant-heavy diet. “The question always comes up about the evolution of umami taste: In humans, our receptor is narrowly tuned to glutamate, and we never had a good answer for why,” says Maude Baldwin, a sensory biologist at the Max Planck Institute for Ornithology in Germany. She was not involved in the new work, but coauthored a 2014 study with Yasuka Toda, who is also a coauthor on the new paper, showing that the T1R1/T1R3 receptor is responsible for sweet taste in hummingbirds. In the new study, the authors find “that this narrow tuning has evolved convergently multiple times [and] that it’s related to folivory,” she says, calling the paper “a hallmark, fantastic study, and one that will become a textbook example of how taste evolution can relate to diet and how to address these types of questions in a rigorous, comprehensive manner.” In 2011, Toda, who was then at the University of Tokyo and now leads a group at Meiji University in Japan, and Takumi Misaka of the University of Tokyo developed a strategy to use cultured cells to analyze the function of taste receptors. They used the technique to tease out the parts of the human T1R1/T1R3 that differed from that of mice and thus underlie the high glutamate sensitivity in the human receptor, work that they published in 2013. © 1986–2021 The Scientist.

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 27986 - Posted: 09.13.2021

By Nicholas Bakalar Many animals are known to use tools, but a bird named Bruce may be one of the most ingenious nonhuman tool inventors of all: He is a disabled parrot who has designed and uses his own prosthetic beak. Bruce is a kea, a species of parrot found only in New Zealand. He is about 9 years old, and when wildlife researchers found him as a baby, he was missing his upper beak, probably because it had been caught in a trap made for rats and other invasive mammals the country was trying to eliminate. This is a severe disability, as kea use their dramatically long and curved upper beaks for preening their feathers to get rid of parasites and to remove dirt and grime. But Bruce found a solution: He has taught himself to pick up pebbles of just the right size, hold them between his tongue and his lower beak, and comb through his plumage with the tip of the stone. Other animals use tools, but Bruce’s invention of his own prosthetic is unique. Researchers published their findings Friday in the journal Scientific Reports. Studies of animal behavior are tricky — the researchers have to make careful, objective observations and always be wary of bias caused by anthropomorphizing, or erroneously attributing human characteristics to animals. “The main criticism we received before publication was, ‘Well, this activity with the pebbles may have been just accidental — you saw him when coincidentally he had a pebble in his mouth,’” said Amalia P.M. Bastos, an animal cognition researcher at the University of Auckland and the study’s lead author. “But no. This was repeated many times. He drops the pebble, he goes and picks it up. He wants that pebble. If he’s not preening, he doesn’t pick up a pebble for anything else.” Dorothy M. Fragaszy, an emerita professor of psychology at the University of Georgia who has published widely on animal behavior but was unacquainted with Bruce’s exploits, praised the study as a model of how to study tool use in animals. © 2021 The New York Times Company

Keyword: Intelligence; Evolution
Link ID: 27984 - Posted: 09.11.2021

Virginia Morell Goffin’s cockatoos (Cacatua goffiniana) are so smart they’ve been compared to 3-year-old humans. But what 3-year-old has made their own cutlery set? Scientists have observed wild cockatoos, members of the parrot family, crafting the equivalent of a crowbar, an ice pick, and a spoon to pry open one of their favorite fruits. This is the first time any bird species has been seen creating and using a set of tools in a specific order—a cognitively challenging behavior previously known only in humans, chimpanzees, and capuchin monkeys. The work “supports the idea that parrots have a general [type of] intelligence that allows them to innovate creative solutions to the problems they run into in nature,” says Alex Taylor, a biologist who studies New Caledonian crows at the University of Auckland. “[It] establishes this species as one of the avian family’s most proficient wild tool users.” The discovery happened serendipitously when behavioral ecologist Mark O’Hara was working with wild but captive birds in a research aviary on Yamdena Island in Indonesia. “I’d just turned away, and when I looked back, one of the birds was making and using tools,” says O’Hara, of the Messerli Research Institute. “I couldn’t believe my eyes!” The Goffin’s cockatoo is known for being a clever and innovative social learner. In captivity, the birds have solved complex puzzle boxes and invented rakelike tools to retrieve objects. Several other birds, including hyacinth macaws and New Caledonian crows, make and use tools in the wild, often to extract food, but none seems to make a set of tools. For the new study, O’Hara and his colleagues traveled to this cockatoo’s home on Indonesia’s Tanimbar Islands. The birds live high in the tropical forest canopy, making them difficult to observe. The scientists spent almost 900 hours looking up to watch wild cockatoos feed, but didn’t witness tool use.

Keyword: Learning & Memory; Intelligence
Link ID: 27974 - Posted: 09.01.2021

By Carolyn Wilke Some female hummingbirds don flashy feathers to avoid being bothered by other hummingbirds, a new study suggests. Male white-necked jacobin hummingbirds (Florisuga mellivora) have bright blue heads and throats. Females tend to have more drab hues, but some sport the blue coloring too. Appearing fit and fine to impress potential mates can often explain animals’ vibrant colors. But mate choice doesn’t seem to drive these females’ pretty plumage since males don’t appear to prefer the blue females. Instead, bright colors may help lady birds blend in with the guys, and as a result, feed for longer without harassment from other hummingbirds, researchers report August 26 in Current Biology. Beyond vying for mates, animals often also compete for territory, parental attention, social ranks and food (SN: 4/7/16). Mating choices don’t capture all those other interactions and can’t always explain animals’ looks, says Jay Falk, an evolutionary biologist at the University of Washington in Seattle. To begin investigating why some female jacobins have colorful blue plumage, Falk and colleagues captured and released over 400 of the birds in Gamboa, Panama, using genetics to determine their sex. Most females had drab colors — olive green heads and backs and mottled throats. But nearly 30 percent of females had the shimmery blue noggins that all juveniles have and that are characteristic of adult males. © Society for Science & the Public 2000–2021.

Keyword: Sexual Behavior; Evolution
Link ID: 27969 - Posted: 08.28.2021