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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.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28321 - Posted: 05.11.2022

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.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 28266 - Posted: 04.02.2022

Dominique Potvin When we attached tiny, backpack-like tracking devices to five Australian magpies for a pilot study, we didn’t expect to discover an entirely new social behaviour rarely seen in birds. Our goal was to learn more about the movement and social dynamics of these highly intelligent birds, and to test these new, durable and reusable devices. Instead, the birds outsmarted us. As our new research paper explains, the magpies began showing evidence of cooperative “rescue” behaviour to help each other remove the tracker. While we’re familiar with magpies being intelligent and social creatures, this was the first instance we knew of that showed this type of seemingly altruistic behaviour: helping another member of the group without getting an immediate, tangible reward. As academic scientists, we’re accustomed to experiments going awry in one way or another. Expired substances, failing equipment, contaminated samples, an unplanned power outage—these can all set back months (or even years) of carefully planned research. For those of us who study animals, and especially behaviour, unpredictability is part of the job description. This is the reason we often require pilot studies. Our pilot study was one of the first of its kind—most trackers are too big to fit on medium to small birds, and those that do tend to have very limited capacity for data storage or battery life. They also tend to be single-use only. A novel aspect of our research was the design of the harness that held the tracker. We devised a method that didn’t require birds to be caught again to download precious data or reuse the small devices. © 1986–2022 The Scientist.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28218 - Posted: 02.26.2022

ByMichael Price When it comes to killing and eating other creatures, chimpanzees—our closest relatives—have nothing on us. Animal flesh makes up much more of the average human’s diet than a chimp’s. Many scientists have long suggested our blood lust ramped up about 2 million years ago, based on the number of butchery marks found at ancient archaeological sites. The spike in calories from meat, the story goes, allowed one of our early ancestors, Homo erectus, to grow bigger bodies and brains. But a new study argues the evidence behind this hypothesis is statistically flawed because it fails to account for the fact that researchers have focused most of their time and attention on later sites. As a result of this unequal “sampling effort” over time at different sites, the authors say, it’s impossible to know how big a role meat eating played in human evolution. Even before the study, many experts suspected the link between carnivory and bigger brains and bodies in early humans might be complex, says Rachel Carmody, an evolutionary biologist at Harvard University who wasn’t involved in the work. The new results, though, “take the important step of demonstrating empirically that controlling for sampling effort actually changes the interpretation.” To conduct the study, W. Andrew Barr, a paleoanthropologist at George Washington University, and colleagues reviewed previously reported data on the appearance of butchery marks at nine archaeological hotbeds of early human activity across eastern Africa spanning 2.6 million to 1.2 million years ago. As expected, the scientist found an increase in the number of cutmarks on animal bones beginning about 2 million years ago. However, the researchers noticed that archaeologists tended to find more cutmarks at the sites that have received the most research attention. In other words, the more time and effort researchers poured into a site, the more likely they were to discover evidence of meat eating. © 2022 American Association for the Advancement of Science.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 28169 - Posted: 01.26.2022

Chloe Tenn Whether they’re predicting the outcomes of sports games or opening jars, the intelligence of octopuses and their cephalopod kin has fascinated avid sports fans and scientists alike (not that the two groups are mutually exclusive). However, insights into the animals’ brains have been limited, as structural data has come from low-tech methods such as dissection. Wen-Sung Chung, a University of Queensland Brain Institute neurobiologist who focuses on marine species, explains that octopuses have “probably the biggest centralized brain in invertebrates,” with multiple layers and lobes. Some species have more than 500 million neurons, he adds—compared to around 70 million in lab mice—making cephalopods especially intriguing as models for neuroscience. Chung and his colleagues decided to bring cephalopod neuroscience into the 21st century: using cutting-edge MRI, they probed the brains of four cephalopod species. They were especially interested in exploring whether cephalopod brain structures reflect the environments they live in. Indeed, the team reports numerous structural differences between species that live on reefs and those that dwell in deeper waters in a November 18 Current Biology paper. Giovanna Ponte, an evolutionary marine biologist at Stazione Zoologica Anton Dohrn Napoli in Italy who was not involved with the work, tells The Scientist that while this isn’t the first study to look for neurological correlates underlying ecological differences in cephalopods, it offers a new technological approach to investigating these animals’ brain morphology and diversity, and most importantly, “is the first time that there is . . . a comparative approach between different species.” © 1986–2022 The Scientist.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 2: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 28166 - Posted: 01.22.2022

By Carl Zimmer Edward O. Wilson, a biologist and author who conducted pioneering work on biodiversity, insects and human nature — and won two Pulitzer Prizes along the way — died on Sunday in Burlington, Mass. He was 92. His death was announced on Monday by the E.O. Wilson Biodiversity Foundation. When Dr. Wilson began his career in evolutionary biology in the 1950s, the study of animals and plants seemed to many scientists like a quaint, obsolete hobby. Molecular biologists were getting their first glimpses of DNA, proteins and other invisible foundations of life. Dr. Wilson made it his life’s work to put evolution on an equal footing. “How could our seemingly old-fashioned subjects achieve new intellectual rigor and originality compared to molecular biology?” he recalled in 2009. He answered his own question by pioneering new fields of research. As an expert on insects, Dr. Wilson studied the evolution of behavior, exploring how natural selection and other forces could produce something as extraordinarily complex as an ant colony. He then championed this kind of research as a way of making sense of all behavior — including our own. As part of his campaign, Dr. Wilson wrote a string of books that influenced his fellow scientists while also gaining a broad public audience. “On Human Nature” won the Pulitzer Prize for general nonfiction in 1979; “The Ants,” which Dr. Wilson wrote with his longtime colleague Bert Hölldobler, won him his second Pulitzer, in 1991. © 2021 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 28125 - Posted: 12.29.2021

Rafael Yuste Michael Levin In the middle of his landmark book On the Origin of Species, Darwin had a crisis of faith. In a bout of honesty, he wrote, “To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I confess, absurd in the highest degree.” While scientists are still working out the details of how the eye evolved, we are also still stuck on the question of how intelligence emerges in biology. How can a biological system ever generate coherent and goal-oriented behavior from the bottom up when there is no external designer? In fact, intelligence—a purposeful response to available information, often anticipating the future—is not restricted to the minds of some privileged species. It is distributed throughout biology, at many different spatial and temporal scales. There are not just intelligent people, mammals, birds and cephalopods. Intelligent, purposeful problem-solving behavior can be found in parts of all living things: single cells and tissues, individual neurons and networks of neurons, viruses, ribosomes and RNA fragments, down to motor proteins and molecular networks. Arguably, understanding the origin of intelligence is the central problem in biology—one that is still wide open. In this piece, we argue that progress in developmental biology and neuroscience is now providing a promising path to show how the architecture of modular systems underlies evolutionary and organismal intelligence. © 2021 Scientific American

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28118 - Posted: 12.18.2021

By Bruce Bower Evidence that cross-continental Stone Age networking events powered human evolution ramped up in 2021. A long-standing argument that Homo sapiens originated in East Africa before moving elsewhere and replacing Eurasian Homo species such as Neandertals has come under increasing fire over the last decade. Research this year supported an alternative scenario in which H. sapiens evolved across vast geographic expanses, first within Africa and later outside it. The process would have worked as follows: Many Homo groups lived during a period known as the Middle Pleistocene, about 789,000 to 130,000 years ago, and were too closely related to have been distinct species. These groups would have occasionally mated with each other while traveling through Africa, Asia and Europe. A variety of skeletal variations on a human theme emerged among far-flung communities. Human anatomy and DNA today include remnants of that complex networking legacy, proponents of this scenario say. It’s not clear precisely how often or when during this period groups may have mixed and mingled. But in this framework, no clear genetic or physical dividing line separated Middle Pleistocene folks usually classed as H. sapiens from Neandertals, Denisovans and other ancient Homo populations. “Middle Pleistocene Homo groups were humans,” says paleoanthropologist John Hawks of the University of Wisconsin–Madison. “Today’s humans are a remix of those ancient ancestors.” © Society for Science & the Public 2000–2021.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 28111 - Posted: 12.15.2021

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.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
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.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28065 - Posted: 11.06.2021

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

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 28026 - Posted: 10.09.2021

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

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
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

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 28005 - 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

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28001 - Posted: 09.22.2021

By Priyanka Runwal Brain tissue is innately squishy. Unlike bones, shells or teeth, it is rich in fat and rots quickly, seldom making an appearance in the fossil record. So when Russell Bicknell, an invertebrate paleontologist at the University of New England in Australia, noticed a pop of white near the front of a fossilized horseshoe crab body where the animal’s brain would have been, he was surprised. A closer look revealed an exceptional imprint of the brain along with other bits of the creature’s nervous system. Unearthed from the Mazon Creek deposit in northeastern Illinois, and dating back 310 million years, it’s the first fossilized horseshoe crab brain ever found. Dr. Bicknell and his colleagues reported the find last month in the journal Geology. “These kinds of fossils are so rare that if you happen to stumble upon one, you’d generally be in shock,” he said. “We’re talking a needle-in-a-haystack level of wow.” The find helps fill a gap in the evolution of arthropod brains and also shows how little they have changed over hundreds of millions of years. Soft-tissue preservation requires special conditions. Scientists have found brains encased in fossilized tree resin, better known as amber, that were less than 66 million years old. They have also found brains preserved as flattened carbon films, sometimes replaced or overlaid by minerals in shale deposits that are more than 500 million years old. Such deposits include corpses of ocean-dwelling arthropods that sank to the seafloor, were rapidly buried in mud and remained shielded from immediate decay in the low-oxygen environment. However, the fossilized brain of Euproops danae, which is kept in a collection at the Yale Peabody Museum of Natural History, required a different set of conditions to be preserved. © 2021 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 27956 - Posted: 08.21.2021

By Cara Giaimo Giraffes seem above it all. They float over the savanna like two-story ascetics, peering down at the fray from behind those long lashes. For decades, many biologists thought giraffes extended this treatment to their peers as well, with one popular wildlife guide calling them “aloof” and capable of only “the most casual” associations. 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. But more recently, as experts have paid closer attention to these lanky icons, a different social picture has begun to emerge. Female giraffes are now known to enjoy yearslong bonds. They have lunch buddies, stand guard over dead calves and stay close with their mothers and grandmothers. Females even form shared day care-like arrangements, called crèches, in which they take turns babysitting and feeding each others young. Observations like these have reached a critical mass, said Zoe Muller, a wildlife biologist who completed her Ph.D. at the University of Bristol in England. She and Stephen Harris, also at Bristol, recently reviewed hundreds of giraffe studies to look for broader patterns. Their analysis, published on Tuesday in the journal Mammal Review, suggests that giraffes are not loners, but socially complex creatures, akin to elephants or chimpanzees. They’re just a little more subtle about it. Dr. Muller’s sense of giraffes as secret socialites began in 2005, when she was researching her master’s thesis in Laikipia, Kenya. There to collect data on antelopes, she found herself drawn to the ganglier ungulates. “They are so weird to look at,” she said. “If somebody described them to you, you wouldn’t believe they even really existed.” After noticing that the same giraffes tended to spend time together — they looked “like teenagers hanging out,” she said — Dr. Muller started to read up on their lifestyles. “I was really surprised to see that all the scientific books said that they were completely non-sociable,” she said. “I thought, ‘Well, hang on. That’s not what I see at all.’” © 2021 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 27945 - Posted: 08.11.2021

By Jaime Chambers Wiggles and wobbles and a powerful pull toward people — that’s what 8-week-old puppies are made of. From an early age, dogs outpace wolves at engaging with and interpreting cues from humans, even if the dogs have had less exposure to people, researchers report online July 12 in Current Biology. The result suggests that domestication has reworked dogs’ brains to make the pooches innately drawn to people — and perhaps to intuit human gestures. Compared with human-raised wolf pups, dog puppies that had limited exposure to people were still 30 times as likely to approach a strange human, and five times as likely to approach a familiar person. “I think that is by far the clearest result in the paper, and is powerful and meaningful,” says Clive Wynne, a canine behavioral scientist at Arizona State University in Tempe who was not involved in the study. Wolf pups are naturally less entranced by people than dogs are. “When I walked into the [wolf] pen for the first time, they would all just run into the corner and hide,” says Hannah Salomons, an evolutionary anthropologist studying dog cognition at Duke University. Over time, Salomons says, most came to ignore her, “acting like I was a piece of furniture.” But dogs can’t seem to resist humans’ allure (SN: 7/19/17). They respond much more readily to people, following where a person points, for example. That ability may seem simple, but it’s a skill even chimpanzees — humans’ close relatives — don’t show. Human babies don’t learn how to do it until near their first birthday. © Society for Science & the Public 2000–2021

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27906 - Posted: 07.14.2021

By Veronique Greenwood Captive cuttlefish require entertainment when they eat. Dinner and a show — if they can’t get live prey, then they need some dancing from a dead shrimp on a stick in their tank. When the food looks alive, the little cephalopods, which look like iridescent footballs with eight short arms and two tentacles, are more likely to eat it. Because a person standing before them has to jiggle it, the animals start to recognize that mealtime and a looming human-shaped outline go together. As soon as a person walks into the room, “they all swim to the front of the tank saying, give me food!” said Trevor Wardill, a biologist at the University of Minnesota who studies cuttlefish vision. You may get a squirt of water from a cuttlefish’s siphon if you don’t feed them, though. Alexandra Schnell, a comparative psychologist at the University of Cambridge, recalled some who sprayed her if she was even a little slow with the treats. It’s the kind of behavior that researchers who’ve worked with cuttlefish sometimes remark on: The critters have character. But they do not have the name recognition of their cousins — the octopus and the squid. Even Tessa Montague, a neuroscientist who today studies cuttlefish at Columbia University, hadn’t really heard of them until an aquarium visit during graduate school. “Octopus are obviously part of lots of children’s story books,” she notes. Cuttlefish were not present. During the last week of a course at the Marine Biological Laboratory in Woods Hole, Mass., though, she heard a talk by Bret Grasse, whom she called a “cephalopod guru.” “He said they have three hearts, green blood and one of the largest brains among invertebrates,” she said. “And they can regenerate their limbs, they can camouflage. Within about 30 seconds, I had basically planned out my entire life. That lunchtime I went to the facility where he was culturing all these animals. My entire scientific career flashed in front of me. I was like, this is it, this is what I’ve been looking for.” © 2021 The New York Times Company

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 27903 - Posted: 07.10.2021

Rebecca Hersher Big bodies are good for cold places. That's the gist of a foundational rule in ecology that has been around since the mid-1800s: Animals that live in colder places tend to have larger bodies, especially birds and mammals that need to regulate their body temperatures. For example, some of the largest whale and bear species have evolved in the coldest reaches of the planet. The rule applies broadly to modern humans too. Populations that evolved in colder places generally have bigger bodies. That's also true of human ancestors, a new study finds. The research offers conclusive evidence that human body size and climate are historically connected. In general, our ancient relatives got much larger as they evolved. "Over the last million years, you see that body size changes by about 50% and brain size actually triples, which is a lot," explains Andrea Manica, an evolutionary ecologist at the University of Cambridge. "And there have been all sorts of theories about what might have underpinned those two big changes in size." Article continues after sponsor message Manica and a team of paleontologists and climate scientists in Germany and the United Kingdom set out to test one of those theories: that the local climate was driving brain and body growth. They examined about 300 fossils of human ancestors collected in Europe, Asia and Africa, and they used the same basic climate data that scientists use to predict future climate change to estimate instead temperature and precipitation over the last million years. © 2021 npr

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 27901 - Posted: 07.10.2021

By Bruce Bower A fossil skull nicknamed “Dragon Man” has surfaced in China under mysterious circumstances, with big news for Neandertals. Dragon Man belonged to a previously unrecognized Stone Age species that replaces Neandertals as the closest known relatives of people today, researchers say. A nearly complete male skull now housed in the Geoscience Museum of Hebei GEO University in Shijiazhuang, China, represents a species dubbed Homo longi by Hebei GEO paleoanthropologist Xijun Ni and his colleagues. The scientists describe the skull, which dates to at least 146,000 years ago, and analyze its position in Homo evolution in three papers published June 25 in The Innovation. Qiang Ji, a paleontologist also at Hebei GEO, received the skull in 2018 from a farmer who said the fossil had been dug up by a coworker of his grandfather’s in 1933. During bridge construction over a river in Harbin, China, the worker allegedly scooped the skull out of river sediment. Whether or not that story is true, this fossil could help answer questions about a poorly understood period of human evolution. “The Harbin cranium presents a combination of features setting it apart from other Homo species,” Ji says. The name H. longi derives from a Chinese term for the province where it was found, which translates as “dragon river.” That term inspired the nickname Dragon Man. As in H. sapiens, the Harbin skull held a large brain situated atop a relatively short face and small cheek bones. But traits such as a long, low braincase, thick brow ridges, large molars and almost square eye sockets recall several extinct Homo populations or species, including Neandertals and H. heidelbergensis (SN: 4/1/20). © Society for Science & the Public 2000–2021

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
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Link ID: 27878 - Posted: 06.26.2021