By Bruce Bower Homo erectus, a humanlike species that dispersed from Africa into parts of Europe and Asia roughly 2 million years ago, eventually reached the Indonesian island of Java before dying out. Scientists say they have now resolved a controversy over just how long ago the last known H. erectus inhabited the Southeast Asian island. New evidence narrows the timing of this hominid’s final stand on Java to between 117,000 and 108,000 years ago, says a team led by geochronologists Yan Rizal of Indonesia’s Bandung Institute of Technology and Kira Westaway of Macquarie University in Sydney. The scientists present their results December 18 in Nature. If the findings hold up to scrutiny, the fossils would be the last known occurrence of H. erectus anywhere in the world, and would show that the hominid was part of a complex interplay among different Homo species in Southeast Asia that started more than 100,000 years ago. Excavations at Java’s Ngandong site from 1931 to 1933 uncovered 12 skullcaps and two lower leg bones from H. erectus. Since then, uncertainty about how Ngandong sediment layers formed and confusion about the original location of the excavated fossils has led to dramatically contrasting age estimates for the finds. A 1996 report in Science dated the Ngandong specimens to between 53,000 and 27,000 years ago, suggesting that H. erectus had lived alongside Homo sapiens in Indonesia (SN: 12/14/96). But a more recent analysis greatly increased the estimated age of the Java fossils, dating them to around 550,000 years ago (SN: 4/16/10). © Society for Science & the Public 2000–2019

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26905 - Posted: 12.19.2019

By Bruce Bower An ancient ape that was larger than a full-grown male gorilla has now revealed molecular clues to its evolutionary roots. Proteins extracted from a roughly 1.9-million-year-old tooth of the aptly named Gigantopithecus blacki peg it as a close relative of modern orangutans and their direct ancestors, say bioarchaeologist Frido Welker of the University of Copenhagen and his colleagues. Protein comparisons among living and fossil apes suggest that Gigantopithecus and orangutan forerunners diverged from a common ancestor between around 10 million and 12 million years ago, Welker’s group reports November 13 in Nature. Since it was first described in 1935, based on a molar purchased from a traditional Chinese drugstore in Hong Kong, G. blacki has stimulated debate over its evolutionary links to other ancient apes. Almost 2,000 isolated teeth and four partial jaws of G. blacki have since been found in southern China and nearby parts of Southeast Asia. G. blacki fossils date from around 2 million to almost 300,000 years ago. The sizes of individual teeth and jaws indicate that G. blacki weighed between 200 and 300 kilograms. Proteins preserve better in teeth and bones than DNA does, but both molecular forms break down quickly in hot, humid settings. “We were surprised to find any proteins this old at all, especially in a fossil from a subtropical environment,” Welker says. Proteins consisting of chains of amino acids can be used to sort out living and fossil species of various animals, including hominids (SN: 5/1/19). © Society for Science & the Public 2000–2019

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26818 - Posted: 11.14.2019

By Karinna Hurley Part of the Museum of Natural History in Paris, the Jardin des Plantes, on the left bank of the Seine River, hosts a collection of galleries and gardens. A couple of miles away, the larger museum also includes the Museum of Mankind, which is, in part, an exploration of what it means to be human. There, like in many other museums worldwide, you can view a collection of stone tools used by the earliest humans. Tool use was long believed to be unique to our species—a defining feature, like language. Utilizing objects to achieve goals is not just a demonstration of advanced cognitive capabilities; it is largely through our symbolic and material tools that we share and transmit culture. In 1960 primatologist Jane Goodall observed wild chimpanzees making and using tools. A connection between humans and other animals, in how we think and learn, was captivating news. Since then, scientists have gone on to establish tool use in a relatively small number of other species. And observations of learning to use a tool from other group members, rather than instinctively, have been even more rare—until now. The Jardin des Plantes is also home to a special couple, Priscilla and Billie. Along with at least one of their daughters, these Visayan warty pigs—residents of the garden’s zoo—are the first in any pig species to be identified using tools and, even more remarkably, to apparently transmit this behavior through social learning. The discovery was made by chance by ecologist Meredith Root-Bernstein, who was watching the family from outside its enclosure. Priscilla, working on building a nest, picked up a piece of bark in her mouth and used it to aid her digging. For six weeks Root-Bernstein frequently returned to the zoo to try to again catch her in the act. Although she didn’t do so, she did notice the digging tool moved among different areas of the enclosure and always near a recently constructed nest. © 2019 Scientific American

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: 26817 - Posted: 11.14.2019

By Elizabeth Preston A pack of baldheaded, boldly plumaged birds steps through the grass shoulder to shoulder, red eyes darting around. They look like middle schoolers seeking a cafeteria table at lunchtime. Perhaps they’re not so different. A study published Monday in Current Biology shows that the vulturine guineafowl of eastern Africa, like humans, have many-layered societies. In the past, scientists hypothesized that such social structures require a lot of brainpower. But the pea-brained guineafowl are revealing the flaws in that assumption. Damien Farine, who led the research and is an ornithologist at the Max Planck Institute of Animal Behavior who studies collective behavior, first worked in Kenya during his postdoctoral research on baboon societies. Baboons are a model for researchers trying to understand how human society evolved. Some kinds of baboons live in groups within groups, a structure that’s called a multilevel society. “Humans are the classic multilevel society,” Dr. Farine said. Imagine a human family living in a village: The family might be friendly with other families within the village, which in turn might have ties to neighboring villages, and so on. “People have long hypothesized that living in complex society is one of the reasons why we’ve evolved such large brains,” Dr. Farine said. Researchers have found evidence for multilevel societies in some other large-brained mammals, such as monkeys, elephants, giraffes and sperm whales. But as Dr. Farine studied baboons, he also watched the vulturine guineafowl wandering around his study site. “I was really struck by the social behavior that they exhibited,” he said. These hefty birds can fly, but rarely choose to. Instead, they stroll across the landscape in packs, often walking so closely that their bodies touch. They may chase each other or fight to maintain their strict hierarchies. But at other times they engage in friendly behaviors like sharing food. Their groups are unusually large for birds, sometimes including 60 or more individuals. And while most other social birds are very territorial, Dr. Farine says, groups of vulturine guineafowl don’t mind sharing turf. © 2019 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26789 - Posted: 11.05.2019

By Carl Zimmer Evolutionary biologists retrace the history of life in all its wondrous forms. Some search for the origin of our species. Others hunt for the origin of birds. On Thursday, a team of researchers reported an important new insight into the origin of zombies — in this case, ants zombified by a fungus. Here’s how it works: Sometimes an ant, marching about its business outdoors, will step on a fungal spore. It sticks to the ant’s body and slips a fungal cell inside. The fungus, called Ophiocordyceps, feeds on the ant from within and multiplies into new cells. But you wouldn’t know it, because the ant goes on with its life, foraging for food to bring back to the nest. All the while, the fungus keeps growing until it makes up nearly half of the ant’s body mass. When Ophiocordyceps is finished feeding on its host, the fungal cells gather inside the ant’s body. They form a mat and push needlelike projections into the ant’s muscle cells. The fungal cells also send chemical signals to the ant’s brain, causing the host to do something strange. The ant departs its nest and climbs a nearby plant. In the tropics, where many species of Ophiocordyceps live, the fungus drives ants upward, to a leaf above the ground. The ant bites down, its jaws locking as it dies. The fungus sends out sticky threads that glue the corpse to the leaf. And now it is ready to take the next step in its life cycle: Out of the ant’s head bursts a giant stalk, which showers spores onto the ant trails below. “The ants are walking over a minefield,” said David Hughes, an expert on Ophiocordyceps at Pennsylvania State University. © 2019 The New York Times Company

Related chapters from BN: Chapter 1: Introduction: Scope and Outlook; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 20:
Link ID: 26754 - Posted: 10.25.2019

Tara Boyle Some of Laurie Santos's most insightful research was sparked by an embarrassing incident. One day, monkeys — her research subjects — stole all the fruit she needed to run a study. She left the research site early for the day. On the boat ride home from Cayo Santiago, the island where the monkeys lived, Santos reflected on the monkeys' mischief. "It's not just that we're dumb researchers and they can outsmart us," she says. "They're specifically trying to steal from us when we're not aware of what they're doing." Santos, a professor of psychology at Yale University, decided to study the monkeys' theft. She found that they selectively stole from the person who couldn't see them. "In other words, they're rationally calculating whether or not someone could detect that they're about to do something dastardly," she says. It was behavior befitting a human. Over the years Santos has discovered other similarities in how humans and non-human primates act. She's also pinpointed important differences, helping us understand which capacities are unique to humans. This comparison between humans and other animals, Santos says, is essential for making any claims that humans are unique. "There's no way to study what makes humans special if you only study humans. You actually have to turn to all the other critters in the animal kingdom," she says. © 2019 npr

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26739 - Posted: 10.23.2019

By Rachel Nuwer In the perennial battle over dogs and cats, there’s a clear public relations winner. Dogs are man’s best friend. They’re sociable, faithful and obedient. Our relationship with cats, on the other hand, is often described as more transactional. Aloof, mysterious and independent, cats are with us only because we feed them. Or maybe not. On Monday, researchers reported that cats are just as strongly bonded to us as dogs or infants, vindicating cat lovers across the land. “I get that a lot — ‘Well, I knew that, I know that cats like to interact with me,’” said Kristyn Vitale, an animal behavior scientist at Oregon State University and lead author of the new study, published in Current Biology. “But in science, you don’t know that until you test it.” Research into cat behavior has lagged that into dogs. Cats are not social animals, many scientists assumed — and not as easy to work with. But recent studies have begun to plumb the depth of cats’ social lives. “This idea that cats don’t really care about people or respond to them isn’t holding up,” Ms. Vitale said. In a study in 2017, Ms. Vitale and her colleagues found that the majority of cats prefer interacting with a person over eating or playing with a toy. In a 2019 study, the researchers found that cats adjust their behavior according to how much attention a person gives them. Other researchers have found that cats are sensitive to human emotion and mood, and that cats know their names. Scientists had arrived at conflicting findings about whether cats form attachments to their owners, however, so Ms. Vitale and her colleagues designed a study to more explicitly test the hypothesis. They recruited owners of 79 kittens and 38 adult cats to participate in a “secure base test,” an experiment commonly used to measure bonds that dogs and primates form with caretakers. © 2019 The New York Times Company

Related chapters from BN: Chapter 15: Emotions, Aggression, and Stress; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 26647 - Posted: 09.25.2019

By Eva Frederick There may be honor among thieves, but there certainly isn’t among parasitic wasps. A new study suggests the crypt keeper wasp, whose larvae burrow into the bodies of other wasps and live off their corpses, has more than half a dozen hosts—or, if you prefer, victims. Those victims are typically Bassettia pallida wasps, which lay their eggs in the stems and branches of oak trees, forming swollen bumps called galls or crypts. The crypt keeper wasp (Euderus set) then lays her eggs in the gall, where her larvae either camp out next to the host hatchlings or burrow into their bodies. When a hatchling is ready to chew its way out of the gall, the crypt keeper—through a feat of undiscovered mind control or through simply weakening the host—makes it chew a hole that is too small. That causes the host’s head to get stuck like a cork in a wine bottle. After snacking on the body of the host, the crypt keeper wasp escapes the gall by burrowing out through its host’s head, which is much softer than the tough stem of the plant. © 2019 American Association for the Advancement of Science.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26644 - Posted: 09.25.2019

By Laura Sanders Dog breeders have been shaping the way the animals look and behave for centuries. That meddling in canine evolution has sculpted dogs’ brains, too. A brain-scanning study of 62 purebred dogs representing 33 breeds reveals that dog brains are not all alike — offering a starting point for understanding how brain anatomy relates to behavior. Different breeds had different shapes of various brain regions, distinctions that were not simply the result of head shape or the size of the dogs’ brains or bodies, researchers report September 2 in the Journal of Neuroscience. Through selective breeding, “we have been systematically shaping the brains of another species,” Erin Hecht, an evolutionary neuroscientist at Harvard University, and colleagues conclude. The MRI scans were taken of dogs with normal brain anatomy at the Veterinary Teaching Hospital at the University of Georgia at Athens. While the study wasn’t designed to directly link brain shape to behavior, the results offer some hints. Researchers identified groups of brain areas, such as smell and taste regions, that showed the most variability between breeds. Those groups are involved in specialized behaviors that often serve humans, such as hunting by smell, guarding and providing companionship to people, earlier studies have suggested. © Society for Science & the Public 2000–2019

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26566 - Posted: 09.03.2019

Colin Barras An ancient face is shedding new light on our earliest ancestors. Archaeologists have discovered a 3.8-million-year-old hominin skull in Ethiopia — a rare and remarkably complete specimen that could change what we know about the origins of one of humanity’s most famous ancestors, Lucy. The researchers who discovered the skull say it belongs to a species called Australopithecus anamensis, and it gives scientists their first good look at the face of this hominin. This species was thought to precede Lucy’s species, Australopithecus afarensis. But features of the latest find now suggest that A. anamensis shared the prehistoric Ethiopian landscape with Lucy’s species for at least 100,000 years, the researchers say. This hints that the early hominin evolutionary tree was more complicated than scientists had thought — but other researchers say the evidence isn’t yet conclusive. “Fossil hominin crania are exceptionally rare treasures,” says Carol Ward, a palaeoanthropologist at the University of Missouri in Columbia who wasn’t involved in the analysis. “This to me is the specimen we have been waiting for.” An analysis of the skull is published in Nature1 . Exceptionally preserved A. afarensis lived in East Africa between about 4 million and 3 million years ago. It is important to the understanding of human evolution because it might have been the ape-like species from which the ‘true’ human genus, Homo, evolved about 2.8 million years ago. Over the past few decades, researchers have discovered dozens of fragments of australopithecine fossils in Ethiopia and Kenya that date back more than 4 million years. Most researchers think these older fossils belong to the earlier species, A. anamensis. It’s generally thought that A. anamensis gradually morphed into A. afarensis, implying that the two species never coexisted.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26551 - Posted: 08.29.2019

By Bruce Bower A 20-million-year-old monkey skull that fits in the palm of an adult’s hand may contain remnants of piecemeal brain evolution in ancient primates. Neural landmarks preserved on the skull fit a scenario in which specific primate brain regions expanded or, at times, contracted while other regions remained unchanged, a new study finds. In an early clue to that evolutionary process, researchers say, a small part of the monkey’s brain devoted to odor perception was not counterbalanced by an enlarged visual system, as is typical of primates today. Primate visual systems expanded in size and complexity over millions of years without requiring substantial changes elsewhere in the brain, contend paleontologist Xijun Ni of the Chinese Academy of Sciences in Beijing and colleagues. And comparisons of the skull with fossils of African primates from 30 million years ago or more indicate that major brain structures evolved at different rates in different primate lineages, as did increases in brain size relative to body size, the team reports August 21 in Science Advances. The study adds evidence to the idea that the brains of primates, a group that includes humans, evolved in a piecemeal way, instead of progressively getting bigger overall as time passed. The skull, from an extinct monkey called Chilecebus carrascoensis, was reported discovered in Chile’s Andes Mountains in 1995 by a team led by paleontologist John Flynn of the American Museum of Natural History in New York City. In the new study, Flynn and colleagues used high-resolution scanning and a digital, 3-D cast of the inner surface of the skull’s tiny braincase to reveal impressions made by a set of neural folds. © Society for Science & the Public 2000–2019.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26528 - Posted: 08.22.2019

By Virginia Morell A bold claim about gorilla societies is drawing mixed reviews. Great apes, humans’ closest evolutionary relatives, were thought to lack our social complexity. Chimpanzees, for example, form only small bands that are aggressive toward strangers. But based on years of watching gorillas gather in food-rich forest clearings, a team of scientists has concluded the apes have hierarchical societies similar to those of humans, perhaps to help them exploit rich troves of food. The finding, reported in the current issue of the Proceedings of the Royal Society B, challenges the prevailing notion that such sophisticated societies evolved relatively recently, after humans split from chimpanzees. Instead, these researchers say, the origins of such social systems extend at least as far back as the common ancestor of humans and gorillas, but were lost in chimpanzees. The group has presented “a pretty convincing case for a hierarchical social structure in gorillas,” says Richard Connor, a cetacean biologist and expert on dolphin society at the University of Massachusetts in Dartmouth. But because other primates that are not great apes—notably baboons, geladas, and colobine monkeys—show similar hierarchies, he’s not surprised they have turned up in gorillas, too. Gorillas spend most of their time in dense forests, travel great distances to a new home spot daily, and are slow to get used to observers, making their social lives hard to study. But western gorillas in the Republic of Congo gather periodically at swampy clearings in the forests to feed primarily on the highly abundant vegetation, but also on favorite and rare foods such as certain fig trees that produce massive amounts of fruit only every 3 to 5 years, says Robin Morrison, a zoologist at the University of Cambridge in the United Kingdom and the study’s lead author. © 2019 American Association for the Advancement of Science.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26428 - Posted: 07.18.2019

Ian Sample Science editor A broken skull chiselled from a lump of rock in a cave in Greece is the oldest modern human fossil ever found outside Africa, researchers claim. The partial skull was discovered in the Apidima cave on the Mani peninsula of the southern Peloponnese and has been dated to be at least 210,000 years old. If the claim is verified – and many scientists want more proof – the finding will rewrite a key chapter of the human story, with the skull becoming the oldest known Homo sapiens fossil in Europe by more than 160,000 years. Katerina Harvati, the director of paleoanthropology at the University of Tübingen in Germany, said the skull revealed that at least some modern humans had left Africa far earlier than previously thought and reached further geographically to settle as far away as Europe. Other fossils of early modern humans found in Israel already point to brief excursions out of Africa, where the species evolved, long before the mass exodus during which Homo sapiens spread from the continent about 70,000 years ago and colonised the world. Paleontologists view the excursions as failed dispersals, with the pioneers ultimately dying out and leaving no genetic legacy in people alive today. “Our results indicate that an early dispersal of Homo sapiens out of Africa occurred earlier than previously believed, before 200,000 years ago,” Karvati said. “We’re seeing evidence for human dispersals that are not just limited to one major exodus out of Africa.” © 2019 Guardian News & Media Limited

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26405 - Posted: 07.11.2019

Bruce Bower South American capuchin monkeys have not only hammered and dug with carefully chosen stones for the last 3,000 years, but also have selected pounding tools of varying sizes and weights along the way. Capuchin stone implements recovered at a site in northeastern Brazil display signs of shifts during the last three millennia between a focus on dealing with either relatively small, soft foods or larger, hard-shelled edibles, researchers report. These discoveries, described online June 24 in Nature Ecology & Evolution, are the first evidence of changing patterns of stone-tool use in a nonhuman primate. “It’s likely that local vegetation changes after 3,000 years ago led to changes in capuchin stone tools,” says archaeologist Tomos Proffitt of University College London. The new findings raise the possibility that chimpanzees and macaque monkeys, which also use stones to pound and dig, have shifted their tool-use styles over the long haul, perhaps in response to climate and habitat changes, Proffitt says. Archaeological sites linked to apes and monkeys are rare, though. Previous excavations in West Africa unearthed nut-cracking stones wielded by chimps around 4,300 years ago (SN: 11/21/09, p. 24). Present-day chimps inhabiting the same part of Africa crack nuts with similar-looking rocks. Evidence of long-term changes in tools used by wild capuchins (Sapajus libidinosus) comes from a site in Brazil’s Serra da Capivara National Park. Excavations there have also yielded ancient human stone tools (SN: 10/18/14, p. 14). But the newly unearthed artifacts more closely resemble stone tools used by modern capuchins at the same site (SN: 11/26/16, p. 16), rather than Stone Age human implements, the researchers say. |© Society for Science & the Public 2000 - 2019

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26356 - Posted: 06.25.2019

By Joshua Sokol For half the year, a little brown bird on the northernmost islands of the Galápagos uses its wickedly sharp beak to pick at seeds, nectar and insects. But when the climate dries out, it drinks blood. Yes, there is such a thing as a vampire finch. Yes, it is what it sounds like. Galápagos finches have been used since Darwin’s time to illustrate evolution in action. Even among them, Geospiza septentrionalis is an outlier, one of the few birds in the world to intentionally draw and drink blood. And the species is only found on Wolf and Darwin islands, two of the most remote and off-limits places in the entire archipelago. The vampire finch has a method. First, one bird hops on the back of a resting Nazca booby, pecks at the base of the seabird’s wing, and drinks. Blood stains the booby’s white feathers. Other finches crowd around to wait their turn, or to watch and learn. Because adult boobies can fly away, the attacks are almost never fatal. The only casualties are chicks that flee from the finches on foot and, unable to find their way back, starve. Drinking blood is an unusual diet, and research published last year showed that vampire finches have evolved specialized bacteria in their guts to aid digestion. Even more surprising, according to a paper this week in the journal Philosophical Transactions of the Royal Society B, is that some of these bacteria are similar to ones found in the vampire bats of Central and South America. Se Jin Song, a biologist at the University of California San Diego and the study’s lead author, had previously studied the convergent evolution of gut bacteria. Do disparate animals with the equivalent of fad diets — eating only ants and termites, for instance — develop similar gut microbiota over evolutionary time? © 2019 The New York Times Company

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: 26312 - Posted: 06.10.2019

Bruce Bower People and Neandertals separated from a common ancestor more than 800,000 years ago — much earlier than many researchers had thought. That conclusion, published online May 15 in Science Advances, stems from an analysis of early fossilized Neandertal teeth found at a Spanish site called Sima de los Huesos. During hominid evolution, tooth crowns changed in size and shape at a steady rate, says Aida Gómez-Robles, a paleoanthropologist at University College London. The Neandertal teeth, which date to around 430,000 years ago, could have evolved their distinctive shapes at a pace typical of other hominids only if Neandertals originated between 800,000 and 1.2 million years ago, she finds. Gómez-Robles’ study indicates that, if a common ancestor of present-day humans and Neandertals existed after around 1 million years ago, “there wasn’t enough time for Neandertal teeth to change at the rate [teeth] do in other parts of the human family tree” in order to end up looking like the Spanish finds, says palaeoanthropologist Bernard Wood of George Washington University in Washington, D.C. Many researchers have presumed that a species dubbed Homo heidelbergensis, thought to have inhabited Africa and Europe, originated around 700,000 years ago and gave rise to an ancestor of both Neandertals and Homo sapiens by roughly 400,000 years ago. Genetic evidence that Sima de los Huesos fossils came from Neandertals raised suspicions that a common ancestor with H. sapiens existed well before that (SN Online: 3/14/16). Recent Neandertal DNA studies place that common ancestor at between 550,000 and 765,000 years old. But those results rest on contested estimates of how fast and how consistently genetic changes accumulated over time. |© Society for Science & the Public 2000 - 2019.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26239 - Posted: 05.17.2019

By Cara Giaimo Here’s a pop quiz for you. Tom is taller than Dick. Dick is taller than Harry. Who’s taller, Harry or Tom? If you said Tom, congratulations! You just demonstrated what’s called “transitive inference” — the ability to compare things indirectly, based on previous juxtapositions. But before you pat yourself on the back too much, you should know that this skill was recently demonstrated by another creature: the humble paper wasp that might be living in your backyard right now. In the summer of 2017, researchers at the University of Michigan put two species of paper wasps through a transitive inference test. A statistically significant portion of the time, the wasps passed. Other animals — including rats, geese and cichlid fish — have also exhibited this capacity. But this study, which was published Tuesday in Biology Letters, is the first to successfully showcase it in an invertebrate (honeybees failed a similar test in 2004). Paper wasps are found on every continent except Antarctica. You might be near some right now. “They tend to nest in the eaves of houses, or inside barbecue grills,” said Elizabeth Tibbetts, the study’s lead author. In a previous study, Dr. Tibbetts showed that individual female wasps can identify one another by their distinct facial patterns, which resemble Rorschach ink blots. “When two wasps meet, they learn, ‘Oh, that’s what Suzy looks like,’” she said. “And the next time they meet, they remember who Suzy is.” In the spring, the females spend a lot of time brawling, getting in each other’s faces and trading slaps with their appendages. These matchups look like schoolyard tussles. “Some wasps will be fighting; some wasps will be watching the fights,” said Dr. Tibbetts. “It’s a very exciting time.” The wasps remember the winners and losers, and use them to establish a social hierarchy: the strongest reproduce, while the weaker ones do all the work. © 2019 The New York Times Company

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: 26229 - Posted: 05.11.2019

Matthew Warren Scientists have uncovered the most complete remains yet from the mysterious ancient-hominin group known as the Denisovans. The jawbone, discovered high on the Tibetan Plateau and dated to more than 160,000 years ago, is also the first Denisovan specimen found outside the Siberian cave in which the hominin was uncovered a decade ago — confirming suspicions that Denisovans were more widespread than the fossil record currently suggests. The research marks the first time an ancient human has been identified solely through the analysis of proteins. With no usable DNA, scientists examined proteins in the specimen’s teeth, raising hopes that more fossils could be identified even when DNA is not preserved. “This is fantastic work,” says Katerina Douka, an archaeologist at the Max Planck Institute for the Science of Human History in Jena, Germany, who runs a separate project aiming to uncover Denisovan fossils in Asia. “It tells us that we are looking at the right area.” Until now, everything scientists have learnt about Denisovans has come from a handful of teeth and bone fragments from Denisova Cave in Russia’s Altai Mountains. DNA from these remains revealed that the Denisovans were a sister group to Neanderthals, both descending from a population that split away from modern humans about 550,00–765,000 years ago. And at Denisova Cave, the two groups seem to have met and interbred: a bone fragment described last year belonged an ancient-human hybrid individual who had a Denisovan father and Neanderthal mother.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26198 - Posted: 05.02.2019

By Sam Roberts Ralph Solecki, an archaeologist whose research helped debunk the view of Neanderthals as heartless and brutish half-wits and inspired a popular series of novels about prehistoric life, died on March 20 in Livingston, N.J. He was 101. The cause was pneumonia, his son William said. Starting in the mid-1950s, leading teams from Columbia University, Dr. Solecki discovered the fossilized skeletons of eight adult and two infant Neanderthals who had lived tens of thousands of years ago in what is now northern Iraq. Dr. Solecki, who was also a Smithsonian Institution anthropologist at the time, said physical evidence at Shanidar Cave, where the skeletons were found, suggested that Neanderthals had tended to the weak and the wounded, and that they had also buried their dead with flowers, which were placed ornamentally and possibly selected for their therapeutic benefits. The exhumed bones of a man, named Shanidar 3, who had been blind in one eye and missing his right arm but who had survived for years after he was hurt, indicated that fellow Neanderthals had helped provide him with sustenance and other support. “Although the body was archaic, the spirit was modern,” Dr. Solecki wrote in the magazine Science in 1975. Large amounts of pollen found in the soil at a grave site suggested that bodies might have been ceremonially entombed with bluebonnet, hollyhock, grape hyacinth and other flowers — a theory that is still being explored and amplified. (Some researchers hypothesized that the pollen might have been carried by rodents or bees, but Dr. Solecki’s theory has become widely accepted.) “The association of flowers with Neanderthals adds a whole new dimension to our knowledge of his humanness, indicating he had a ‘soul,’ ” Dr. Solecki wrote. © 2019 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 26131 - Posted: 04.12.2019

By Carl Zimmer In a cave in the Philippines, scientists have discovered a new branch of the human family tree. At least 50,000 years ago, an extinct human species lived on what is now the island of Luzon, researchers reported on Wednesday. It’s possible that Homo luzonensis, as they’re calling the species, stood less than three feet tall. The discovery adds growing complexity to the story of human evolution. It was not a simple march forward, as it once seemed. Instead, our lineage assumed an exuberant burst of strange forms along the way. Our species, Homo sapiens, now inhabits a comparatively lonely world. “The more fossils that people pull out of the ground, the more we realize that the variation that was present in the past far exceeds what we see in us today,” said Matthew Tocheri, a paleoanthropologist at Lakehead University in Canada, who was not involved in the new discovery. In the early 2000s, Armand Salvador Mijares, a graduate student at the University of the Philippines, was digging at Callao Cave, on Luzon, for traces of the first farmers on the Philippines. Soon, he decided to dig a little deeper. Researchers on the Indonesian island of Flores had discovered the bones of an extraordinary humanlike species about 60,000 years old. The scientists named it Homo floresiensis. Some features were similar to ours, but in other ways Homo floresiensis more closely resembled other hominins (the term scientists use for modern humans and other species in our lineage). © 2019 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
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Link ID: 26126 - Posted: 04.11.2019