Anthropologists' research unveils early stone plaza in the Andes

Two University of Wyoming anthropology professors have discovered one of the earliest circular plazas in Andean South America, showcasing monumental megalithic architecture, which refers to construction that uses large stones placed upright with no mortar.

Located at the Callacpuma archaeological site in the Cajamarca Basin of northern Peru, the plaza is built with large, vertically placed megalithic stones -- a construction method previously unseen in the Andes.

Associate Professor Jason Toohey, project lead, and Professor Melissa Murphy have been researching this topic since the project's inception in 2015.

Excavations took place in the plaza starting in 2018.

Their paper, which reports new data on this earliest known megalithic circular plaza in the northern Andes, is titled "A Monumental Stone Plaza at 4750 BP in the Cajamarca Valley of Peru" and has been published today (Feb.

14) in the peer-reviewed journal Science Advances.

Radiocarbon dating places its initial construction around 4,750 years ago during the Late Preceramic Period, making it one of the earliest instances of such architecture in the Americas.

To better understand this timeline, the team carefully excavated within the plaza, uncovering artifacts related to life in the past and collecting charcoal samples for dating.

All material remains then were cleaned, processed and analyzed in the laboratory.

"This structure was built approximately 100 years before the Great Pyramids of Egypt and around the same time as Stonehenge," Toohey says.

These dates signify that the circular plaza at Callacpuma is the earliest known example of monumental and megalithic architecture in the Cajamarca Valley -- and one of the earliest examples in ancient Peru.

"It was probably a gathering place and ceremonial location for some of the earliest people living in this part of the Cajamarca Valley," Toohey adds.

"These people were living a primarily hunting-and-gathering lifestyle and probably had only recently begun growing crops and domesticating animals."

The plaza is formed by two concentric walls and measures about 60 feet in diameter.

The project is led by Toohey and Patricia Chirinos Ogata from the University of California-Santa Barbara.

The team also includes Murphy, as well as undergraduate and graduate students from Peru and the U.S.

Toohey is an anthropological archaeologist who is dedicated to taking a holistic and multidisciplinary approach to the field.

He has conducted fieldwork in the Peruvian Andes since 2003.

The department head for anthropology at UW, Murphy is a biological anthropologist specializing in bioarchaeology and committed to multidisciplinary approaches within anthropology.

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Rise of archery in Andes Mountains dated to 5,000 years ago -- earlier than previous research

When did archery arise in the Americas? And what were the effects of this technology on society?

These questions have long been debated among anthropologists and archaeologists.

But a study led by a University of California, Davis, anthropologist, is shining light on this mystery.

Focusing on the Lake Titicaca Basin in the Andes mountains, anthropologists found through analysis of 1,179 projectile points that the rise of archery technology dates to around 5,000 years ago.

Previous research held that archery in the Andes emerged around 3,000 years ago.

The new research indicates that the adoption of bow-and-arrow technology coincided with both the expansion of exchange networks and the growing tendency for people to reside in villages.

"We think our paper is groundbreaking because it gives us a chance to see how society changed throughout the Andes throughout ancient times by presenting a huge number of artifacts from a vast area of South America," said Luis Flores-Blanco, an anthropology doctoral student and corresponding author of the paper.

"This is among the first instances in which Andean archaeologists have investigated social complexity through the quantitative analysis of stone tools."

The study was published online in November in Quaternary International.

Researchers said increasing social complexity in the region is usually investigated through analysis of monumental architecture and ceramics rather than projectile points, which are historically linked to foraging communities.

Pooling from 10,000 years of history

For the study, the team examined more than a thousand projectile points created over 10,000 years.

Each projectile point originated in the Lake Titicaca Basin, specifically the Ilave and Ramis valleys, which are located southwest and northwest of the basin, respectively.

Flores-Blanco said it's among the highest plateau lands explored and conquered by humans, with Lake Titicaca sitting at an elevation of 12,500 feet.

"At Titicaca, Andeans accomplished the remarkable achievement of domesticating plants like the potato, leaving behind a nutritious legacy that is still appreciated today," he said.

"On top of that, the Tiwanaku were one of the major Andean civilizations that built their vast territory here. Even the Inca Empire claimed this territory was their mythical place of origin. Our study digs even deeper and goes to the roots of this Andean civilization."

In their analysis, Flores-Blanco and his colleagues considered each projectile's date of origin and then measured its length, width, thickness and weight.

They noticed that older projectile points -- from the Early Archaic through the Late Archaic -- were larger.

A significant decrease in size occurred during the Terminal Archaic period, around 5,000 years ago.

The team hypothesized that this size shift indicates a change in preference from spear-throwing technology to bow-and-arrow technology, but without abandoning the old technologies.

In addition, the team compared their projectile data to archaeological data from the region concerning settlement sizes, raw material availability and cranial trauma data.

During the Terminal Archaic period, settlement sizes increased but the total number of settlement sites decreased, researchers said.

Not only that, but the inhabitants lacked signs of social violence, even though they had access to exotic raw materials.

"Based on our discovery, we can suggest that bow-and-arrow technology could have maintained and ensured adherence to emerging social norms that were crucial, such as those observed in the development of new social institutions, like obsidian exchange hubs or among individuals establishing residence in expanding villages," Flores-Blanco said.

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Researchers, Coast Salish people analyze 160-year-old indigenous dog pelt in the Smithsonian's collection

Researchers from the Smithsonian's National Museum of Natural History led a new analysis that sheds light on the ancestry and genetics of woolly dogs, a now extinct breed of dog that was a fixture of Indigenous Coast Salish communities in the Pacific Northwest for millennia. Anthropologist Logan Kistler and evolutionary molecular biologist Audrey Lin analyzed genetic clues preserved in the pelt of "Mutton," the only known woolly dog fleece in the world, to pinpoint the genes responsible for their highly sought-after woolly fur.

The study's findings, published today, Dec. 14, in the journal Science, include interviews contributed by several Coast Salish co-authors, including Elders, Knowledge Keepers and Master Weavers, who provided crucial context about the role woolly dogs played in Coast Salish society.

"Coast Salish traditional perspective was the entire context for understanding the study's findings," said Kistler, the museum's curator of archaeobotany and archaeogenomics.

Coast Salish tribal nations in Washington state and British Columbia bred and cared for woolly dogs for thousands of years. Prized for their thick undercoats, the dogs were sheared like sheep and often kept in pens or on islands to carefully manage their breeding and to care for the canines' health and vitality. Coast Salish weavers used the dogs' wool to craft blankets and other woven items that served a variety of ceremonial and spiritual purposes. Woolly dogs themselves possessed spiritual significance and were often treated as beloved family members. As emblems for many Coast Salish communities, woolly dogs adorned woven baskets and other art forms.

By the mid-19th century, this once thriving dog wool-weaving tradition was in decline. In the late 1850s, naturalist and ethnographer George Gibbs cared for a woolly dog named Mutton. When Mutton died in 1859, Gibbs sent his pelt to the nascent Smithsonian Institution, where the fleece has resided ever since. However, few were aware of the pelt's existence until it was rediscovered in the early 2000s.

Lin first learned about Mutton when she was a Peter Buck postdoctoral fellow at the museum in 2021.

"When I saw Mutton in person for the first time, I was just overcome with excitement," said Lin, who is now a postdoctoral researcher at the American Museum of Natural History. "I had heard from some other people that he was a bit scraggly, but I thought he was gorgeous."

She was surprised to find out that virtually no work had been done on the genetics of woolly dogs, which disappeared around the turn of the 20th century. She teamed up with Kistler and they reached out to several Coast Salish communities to gauge their interest in working together on a potential research project on woolly dogs.

Many in the Coast Salish communities were eager to share their knowledge.

"We were very excited to participate in a study that embraces the most sophisticated Western science with the most established Traditional Knowledge," said Michael Pavel, an Elder from the Skokomish/Twana Coast Salish community in Washington, who remembers hearing about woolly dogs early in his childhood. "It was incredibly rewarding to contribute to this effort to embrace and celebrate our understanding of the woolly dog."

To complement the perspectives they received from Pavel and other Coast Salish people from British Columbia and Washington state (the text from their interviews is available in the study's supplementary materials), Lin, Kistler and their colleagues began analyzing Mutton's genetic code. They sequenced the woolly dog genome and compared it with the genomes of ancient and modern breeds of dogs to determine what set woolly dogs apart. They also identified certain chemical signatures called isotopes in Mutton's pelt to determine the dog's diet and teamed up with noted natural history illustrator Karen Carr to create a life-like reconstruction of what Mutton looked like in the 1850s. Carr's work is the first in-depth reconstruction of a Coast Salish woolly dog in nearly three decades.

Based on the genetic data, the team estimated that woolly dogs diverged from other breeds up to 5,000 years ago -- a date that lines up with archaeological remains from the region. They also discovered that Mutton was genetically similar to pre-colonial dogs from Newfoundland and British Columbia. The researchers estimate that nearly 85% of Mutton's ancestry can be linked to pre-colonial dogs. This ancient ancestry is surprising because Mutton lived decades after the introduction of European dog breeds. This makes it likely that Coast Salish communities continued to maintain woolly dogs' unique genetic makeup until right before the dogs were wiped out.

In total, the team analyzed more than 11,000 different genes in Mutton's genome to determine what gave woolly dogs their fluffy fleece and wool fibers that could be spun together to create yarn. They identified 28 genes that have links to hair growth and follicle regeneration. These included a gene that causes a woolly hair phenotype in humans, and another linked to curly hair in other dogs. Similar genes were even activated in the genomes of woolly mammoths.

However, Mutton's genetics could tell the researchers little about what caused the dogs to decline. Traditionally, scholars have speculated that the arrival of machine-made blankets to the region in the early 19th century made woolly dogs expendable. But insights from Pavel and other traditional experts revealed that it was improbable that such a central part of Coast Salish society could be replaced.

Instead, woolly dogs were likely doomed by numerous factors impacting the Coast Salish tribal nations after European settlers arrived. Due to disease and colonial policies of cultural genocide, displacement and forced assimilation, it likely became increasingly difficult or forbidden for Coast Salish communities to maintain their woolly dogs.

"It was thousands of years of very careful maintenance lost within a couple of generations," Lin said.

But despite their disappearance, the memory of woolly dogs is still embedded into Coast Salish society. And Pavel thinks their understanding of woolly dogs is only getting clearer thanks to the new research effort.

"All of our communities held a certain aspect of knowledge about the woolly dog," Pavel said. "But when woven together, as a result of participating in this study, we now have a much more complete understanding."

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No scientific evidence for cognitively advanced behaviors and symbolism by Homo naledi

A new study has cast doubt on claims that Homo naledi, a small-brained hominin dating to between 335-241,000 years ago, deliberately buried their dead and produced rock art in Rising Star Cave, South Africa.

Three pre-print articles published this year in eLife suggested the recent excavations at the Rising Star Cave system provided evidence of at least three burial features, two in the Dinaledi Chamber and a third in the Hill Antechamber cavity.

The articles claimed the features represented the earliest evidence of deliberate burial by a hominin species, and that Homo naledi lit up dark passageways using fire and intentionally carried the bodies of at least three individuals deep inside the Rising Star Cave system, dug pits, deposited corpses inside the pits, and covered the bodies with sediments.

It was also claimed that the Hill Antechamber feature contained a stone tool in close proximity to the hominin hand.

However, a group of  experts with specialisations in biological anthropology, archaeology, geochronology, and rock art, have now called for a deeper dig into the science behind the findings in a first, peer-reviewed critique published in the Journal of Human Evolution (JHE).

Professor Michael Petraglia from Griffith University's Australian Research Centre for Human Evolution, Professor Andy Herries from La Trobe University, María Martinón-Torres from the National Research Center on Human Evolution in Spain and Diego Garate from the University of Cantabria in Spain co-authored the peer-reviewed article.

The research team conclude the evidence presented so far was not compelling enough to support the deliberate burial of the dead by Homo naledi, nor that they made the purported engravings.

"We really need substantial additional documentation and scientific analyses before we can rule out that natural agents and post-depositional processes were responsible for the accumulation of bodies/body parts and to prove the intentional excavation and filling of pits by Homo naledi," Professor Martinón-Torres said.

Moreover, Professor Petraglia added: "Unfortunately, there is a distinct possibility that the so-called stone artifact next to the hominin hand is a geofact, and not a product of stone tool flaking by Homo naledi."

Professor Herries said: "There is no evidence that Homo naledi lit fires in the cave, purported buring locations could just be from manganese staining and charcoal within the cave remains to be dated. Charcoal from natural fires is not uncommon in caves."

"Detailed analyses are also needed to demonstrate that the so-called 'engravings' are indeed human-made marks, as marks like these can be produced as a product of natural weathering or animal claws," said Dr Garate.

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Challenging prehistoric gender roles: Research finds that women were hunters, too

It's a familiar story to many of us: In prehistoric times, men were hunters and women were gatherers. Women were not physically capable of hunting because their anatomy was different from men. And because men were hunters, they drove human evolution.

But that story's not true, according to research by University of Delaware anthropology professor Sarah Lacy, which was recently published in Scientific American and in two papers in the journal American Anthropologist.

Lacy and her colleague Cara Ocobock from the University of Notre Dame examined the division of labor according to sex during the Paleolithic era, approximately 2.5 million to 12,000 years ago. Through a review of current archaeological evidence and literature, they found little evidence to support the idea that roles were assigned specifically to each sex. The team also looked at female physiology and found that women were not only physically capable of being hunters, but that there is little evidence to support that they were not hunting.

Lacy is a biological anthropologist who studies the health of early humans, and Ocobock is a physiologist who makes analogies between modern day and the fossil record. Friends in graduate school, they collaborated after "complaining about a number of papers that had come out that used this default null hypothesis that cavemen had strong gendered division of labor, the males hunt, females gather things. We were like, 'Why is that the default? We have so much evidence that that's not the case,'" Lacy said.

The researchers found examples of equality for both sexes in ancient tools, diet, art, burials and anatomy.

"People found things in the past and they just automatically gendered them male and didn't acknowledge the fact that everyone we found in the past has these markers, whether in their bones or in stone tools that are being placed in their burials. We can't really tell who made what, right? We can't say, 'Oh, only males flintknap,' because there's no signature left on the stone tool that tells us who made it," Lacy said, referring to the method by which stone tools were made. "But from what evidence we do have, there appears to be almost no sex differences in roles."

The team also examined the question of whether anatomical and physiological differences between men and women prevented women from hunting. They found that men have an advantage over women in activities requiring speed and power, such as sprinting and throwing, but that women have an advantage over men in activities requiring endurance, such as running. Both sets of activities were essential to hunting in ancient times.

The team highlighted the role of the hormone estrogen, which is more prominent in women than men, as a key component in conferring that advantage. Estrogen can increase fat metabolism, which gives muscles a longer-lasting energy source and can regulate muscle breakdown, preventing muscles from wearing down. Scientists have traced estrogen receptors, proteins that direct the hormone to the right place in the body, back to 600 million years ago.

"When we take a deeper look at the anatomy and the modern physiology and then actually look at the skeletal remains of ancient people, there's no difference in trauma patterns between males and females, because they're doing the same activities," Lacy said.

During the Paleolithic era, most people lived in small groups. To Lacy, the idea that only part of the group would hunt didn't make sense.

"You live in such a small society. You have to be really, really flexible," she said. "Everyone has to be able to pick up any role at any time. It just seems like the obvious thing, but people weren't taking it that way."

Man the Hunter

The theory of men as hunters and women as gatherers first gained notoriety in 1968, when anthropologists Richard B. Lee and Irven DeVore published Man the Hunter, a collection of scholarly papers presented at a symposium in 1966. The authors made the case that hunting advanced human evolution by adding meat to prehistoric diets, contributing to the growth of bigger brains, compared to our primate cousins. The authors assumed all hunters were male.

Lacy points to that gender bias by previous scholars as a reason why the concept became widely accepted in academia, eventually spreading to popular culture. Television cartoons, feature films, museum exhibits and textbooks reinforced the idea. When female scholars published research to the contrary, their work was largely ignored or devalued.

"There were women who were publishing about this in the '70s, '80s and '90s, but their work kept getting relegated to, 'Oh, that's a feminist critique or a feminist approach,'" Lacy said. "This was before any of the work on genetics and a lot of the work on physiology and the role of estrogen had come out. We wanted to both lift back up the arguments that they had already made and add to it all the new stuff."

Lacy said the "man the hunter" theory continues to influence the discipline. While she acknowledges that much more research needs to be done about the lives of prehistoric people -- especially women -- she hopes her view that labor was divided among both sexes will become the default approach for research in the future.

For 3 million years, males and females both participated in subsistence gathering for their communities, and dependence on meat and hunting was driven by both sexes, Lacy said.

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Apes may have evolved upright stature for leaves, not fruit, in open woodland habitats

Anthropologists have long thought that our ape ancestors evolved an upright torso in order to pick fruit in forests, but new research from the University of Michigan suggests a life in open woodlands and a diet that included leaves drove apes' upright stature.

The finding sheds light on ape origins and pushes back the origin of grassy woodlands from between 7 million and 10 million years ago to 21 million years ago, during the Early Miocene.

Fruit grows on the spindly peripheries of trees. To reach it, large apes need to distribute their weight on branches stemming from the trunk, then reach out with their hands toward their prize. This is much easier if an ape is upright because it can more easily grab onto different branches with its hands and feet. If its back is horizontal, then its hands and feet are generally underneath the body, making it much harder to move outward to the smaller branches of a tree -- especially if the ape is large bodied.

This is how modern day apes reach fruit, and, it's been theorized, that's why apes evolved to be upright, according to U-M researchers Laura MacLatchy and John Kingston.

But new research centered around a 21-million-year-old fossil ape called Morotopithecus and led by MacLatchy suggests this might not be the case. Instead, researchers think early apes ate leaves and lived in a seasonal woodland with a broken canopy and open, grassy areas. The researchers suggest this landscape, instead of fruit in closed canopy forests, drove apes' upright stature.

Their results are published in Science and are bolstered by a companion paper examining these paleo grassy woodland habitats, published in the same issue of the journal.

"The expectation was: We have this ape with an upright back. It must be living in forests and it must be eating fruit. But as more and more bits of information became available, the first surprising thing we found was that the ape was eating leaves. The second surprise was that it was living in woodlands," said MacLatchy, a paleoanthropologist and professor in the U-M Department of Anthropology.

The two papers grew out of a U.S. National Science Foundation-funded collaboration of international paleontologists, collectively known as the Research on Eastern African Catarrhine and Hominoid Evolution project or REACHE, each of whom focus on different aspects of early ape paleoenvironments. The study led by MacLatchy focuses on a 21-million-year-old site called the Moroto site in eastern Uganda.

There, the group, which included U-M researchers William Sanders and Miranda Cosman, examined fossils found in a single stratigraphic layer, including fossils of the oldest, clearly documented ape, Morotopithecus. Also within this layer were fossils of other mammals, ancient soils called paleosols, and tiny silica particles from plants called phytoliths. The researchers used these lines of evidence to recreate the ancient environment of Morotopithecus.

MacLatchy and Kingston discovered that the plants living in this landscape were what's called "water stressed," meaning they lived through seasonal periods of rain and of aridity. This also means that at least part of the year, apes had to rely on something other than fruit to survive. Together, these findings indicate that Morotopithecus lived in an open woodland punctuated by broken canopy forests composed of trees and shrubs.

"These open environments have been invoked to explain human origins, and it was thought that you started to get these more open, seasonal environments between 10 and 7 million years ago," MacLatchy said. "Such an environmental shift is thought to have been selected for terrestrial bipedalism -- our ancestors started striding around on the ground because the trees were further apart.

"Now that we've shown that such environments were present at least 10 million years before bipedalism evolved, we need to really rethink human origins, too."

The first clue that these ancient apes were eating leaves was in the apes' molars. The molars were very "cresty": they were craggy, with peaks and valleys. Molars like this are used for tearing fibrous leaves apart, while molars used for eating fruit are typically more rounded, MacLatchy said.

The researchers also examined the apes' dental enamel, as well as the dental enamel of other mammals found in the same stratigraphic layer. They found that isotopic ratios -- the abundance of two isotopes of the same element -- in their dental enamel showed that the apes and other mammals had been eating water stressed C3 plants that are more common in open woodland or grassy woodland environments today. C3 plants are primarily woody shrubs and trees while C4 plants are arid-adapted grasses.

"Putting together the locomotion, the diet and the environment, we basically discovered a new model for ape origins," MacLatchy said. "In anthropology, we care a lot about ape evolution because humans are closely related to apes and features like lower back stability represent an arboreal adaptation that may have ultimately given rise to bipedal humans."

Early Miocene C4 grasses and open woodlands

Previously, researchers believed equatorial Africa during the Early Miocene was thickly carpeted with forest, and that open seasonal woodlands and grasslands evolved only between 7 million and 10 million years ago.

But the second paper uses a set of environmental proxies to reconstruct the vegetation structure from nine fossil ape sites across Africa, including the Moroto site, during the Early Miocene. These proxies revealed that C4 grasses were "everywhere" during that time period, said Kingston, a biological anthropologist and associate professor in the U-M Department of Anthropology.

"This paper looks at all these sites, pulls all this data together, and says, 'Look, no matter how you evaluate the data, there's no way you can escape the fact that all these proxies are converging on the same place -- namely, that these environments are open, and they're open with C4 grasses," he said.

"For the first time, we're showing that these grasses are widespread, and it's this general context of open seasonal woodland ecosystems that were integral in shaping the evolution of different mammalian lineages, including and especially in our case, how different ape lineages evolved."

The nine sites are scattered across eastern equatorial Africa, enough to develop a "regional picture" of what the sites' landscapes looked like in the Early Miocene, Kingston said. During this time, the East African Rift was forming. Earth was pulling apart. As a result, the entire region was uplifted, causing huge variation in topography, and therefore, regional climate and vegetation.

"There's mountains and volcanoes, there's cliffs and escarpments and valleys," Kingston said. "The landscape is just physically highly variable, and that, no doubt, is related to the vegetation heterogeneity."

To reconstruct the paleoenvironment at each location, the researchers used carbon isotope analyses of ancient soil organic matter, plant wax biomarkers and phytoliths found at each site. The carbon isotope analyses revealed that a wide range of plants lived in the grasslands, ranging from those that comprise closed canopy to wooded grasslands.

The wax biomarkers -- left over from the waxy material that protects leaves -- also indicate a large variety of shrubs and trees as well as grasses. Phytoliths -- microscopic biosilica bodies that give plants their structure as well as a defense against being eaten -- can tell the researchers the proportion of C4 grasses at a given site and provide further evidence for abundant C4 grasses.

After using these proxies to rebuild the paleoenvironments at these nine sites, the researchers found that C4 grasses were abundant across eastern equatorial Africa, and were a key part of the landscape's heterogeneous habitats. Their data also pushes back the oldest evidence of C4 grass-dominated habitats in Africa and globally by more than 10 million years.

"The findings have transformed what we thought we knew about early apes, and the origin for where, when and why they navigate through the trees and on the ground in multiple different ways," said Robin Bernstein, program director for biological anthropology at the National Science Foundation.

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Extinct 'monkey lemur' shows similarities to fossil humans

Analysis of teeth of extinct lemurs has revealed fascinating clues to the evolution of humans, a University of Otago study has found.

Lead author Dr Ian Towle, of the Sir John Walsh Research Institute in the Faculty of Dentistry, says the "surprisingly large" monkey lemur, Archaeolemur, had novel anatomical features not seen in living lemurs, such as lacking a 'tooth comb' in the front of the mouth for grooming.

"These extinct lemurs are so different to those alive today. They also show fascinating similarities to monkeys and apes, including humans," he says.

The study, published in the American Journal of Biological Anthropology, aimed to assess the diet of Archaeolemur by analysing chipping in 447 teeth, comparing chipping frequencies to those of other primates.

The results were surprising -- with these remarkable extinct lemurs with dentitions resembling baboons in shape; but presenting tooth chipping patterns similar to fossil hominins such as Neanderthals.

"Archaeolemur tooth chipping patterns are unlike any living primate, with their front teeth showing substantial fractures, often with numerous tooth chips on a single tooth, yet very little chipping on their back teeth.

"Similar tooth fracture patterns are observed in fossil hominins, such as Neanderthals. Typically, in Neanderthals these fracture patterns are thought to be related to tool-use behaviours," Dr Towle says.

The results fit with previous research on Archaeolemur, in particular evidence that their large and robust front teeth may have been used to process a diet containing hard and tough foods.

Dr Towle thinks the study raises the "fascinating possibility" that stone tools do not necessarily explain the high rate of fractures on Neanderthal teeth.

"Archaeolemur shows similar tooth chipping patterns, yet there is no evidence to suggest they were capable of, or used, such tools.

"Studying extinct primates not only provides crucial insight into their diet and behaviour, but also elucidates our own evolutionary history."

Given the overlap in skull and dental shape, and potential similarities in diet and behaviour, it is perhaps not surprising that Archaeolemur  was thought to be an ape when first discovered in Madagascar over 100 years ago.

"Archaeolemur is a brilliant example of convergent evolution, showing remarkable similarities to monkeys and apes. This species also highlights the extent to which lemurs in Madagascar diversified into a variety of ecological niches."

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Mystery solved about the origin of the 30,000-year-old Venus of Willendorf

The almost 11 cm high figurine from Willendorf is one of the most important examples of early art in Europe. It is made of a rock called "oolite" which is not found in or around Willendorf. A research team led by the anthropologist Gerhard Weber from the University of Vienna and the two geologists Alexander Lukeneder and Mathias Harzhauser as well as the prehistorian Walpurga Antl-Weiser from the Natural History Museum Vienna have now found out with the help of high-resolution tomographic images that the material from which the Venus was carved likely comes from northern Italy. This sheds new light on the remarkable mobility of the first modern humans south and north of the Alps. The results currently appear in Scientific Reports.

The Venus von Willendorf is not only special in terms of its design, but also in terms of its material. While other Venus figures are usually made of ivory or bone, sometimes also of different stones, oolite was used for the Lower Austrian Venus, which is unique for such cult objects. The figurine found in the Wachau in 1908 and on display in the Natural History Museum in Vienna has so far only been examined from the outside. Now, more than a 100 years later, anthropologist Gerhard Weber from the University of Vienna has used a new method to examine its interior: micro-computed tomography. During several passes, the scientists obtained images with a resolution of up to 11.5 micrometres -- a quality that is otherwise only seen under a microscope. The first insight gained is: "Venus does not look uniform at all on the inside. A special property that could be used to determine its origin," says the anthropologist.

Along with the two geologists Alexander Lukeneder and Mathias Harzhauser from the Natural History Museum in Vienna, who had previously worked with oolites, the team procured comparative samples from Austria and Europe and evaluated them. A complex project: Rock samples from France to eastern Ukraine, from Germany to Sicily were obtained, sawn up and examined under a microscope. The team was supported by the state of Lower Austria, which provided funds for the time-consuming analyses.

The inside also gives information about the outside

The tomographic data from the Venus showed that the sediments were deposited in the rocks in different densities and sizes. In between there were also small remnants of shells and six very dense, larger grains, so-called limonites. The latter explains the previously mysterious hemispherical cavities on the surface of Venus with the same diameter: "The hard limonites probably broke out when the creator of the Venus was carving it," explains Weber: "In the case of the Venus navel, he then apparently made it a virtue out of necessity."

Another finding: The Venus oolite is porous because the cores of the millions of globules (ooides) of which it is comprised had dissolved. This is a great explanation for why the resourceful sculptor chose this material 30,000 years ago: It is much easier to work with. The scientists also identified a tiny shell remnant, just 2.5 millimetres long, and dated it to the Jurassic period. This ruled out all other potential deposits of the rock from the much later Miocene geological era, such as those in the nearby Vienna Basin.

A long way for that time

The research team also analysed the grain sizes of the other samples. Hundreds, sometimes even thousands of grains were marked and measured with image processing programs or even manually. None of the samples within a 200-kilometer radius of Willendorf even remotely matched. The analysis finally showed that the samples from the Venus were statistically indistinguishable from samples from a location in northern Italy near Lake Garda. This is remarkable because it means that the Venus (or at least its material) started a journey from south of the Alps to the Danube north of the Alps.

"People in the Gravettian -- the tool culture of the time -- looked for and inhabited favourable locations. When the climate or the prey situation changed, they moved on, preferably along rivers," explains Gerhard Weber. Such a journey could have taken generations.

One of the two possible routes from the south to the north would lead around the Alps and into the Pannonian Plain and was described in simulations by other researchers a few years ago. The other way to get from Lake Garda to the Wachau would be via the Alps. Whether this was possible more than 30,000 years ago is unclear due to the climate deterioration that began at that time. This would be a rather improbable variant if there had already been continuous glaciers at that time. However, the 730 km long path along the Etsch, the Inn and the Danube had always been below 1,000 meters above sea level, with the exception of 35 kilometres at Lake Reschen.

Possible, but less likely, connection to eastern Ukraine

The statistics clearly point to northern Italy as the origin of the Venus oolite. Nevertheless, there is another interesting place for the origin of the rock. It is in eastern Ukraine, more than 1,600 kilometres linear distance from Willendorf. The samples there do not fit as clearly as those from Italy, but better than all the rest of the sample. An interesting connection here: Venus figures were found in nearby southern Russia, which are somewhat younger, but look very similar to the Venus found in Austria. Genetic results also show that people in Central and Eastern Europe were connected to one another at this time.

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Leafy greens first dished up 3,500 years ago

Over 450 prehistoric pots were examined, 66 of them contained traces of lipids, that is, substances insoluble in water. On behalf of the Nok research team at Goethe University, chemists from the University of Bristol extracted lipid profiles, with the aim of revealing which plants had been used. The results have now been published in "Archaeological and Anthropological Sciences": over a third of the 66 lipid profiles displayed very distinctive and complex distributions -- indicating that different plant species and parts had been processed.

Today, leafy vegetables, for example the cooked leaves of trees such as the baobab (Adansonia digitata) or of the shrubby -- nomen est omen -- bitter leaf (Vernonia amygdalina), accompany many West African dishes. These leafy sauces are enhanced with spices and vegetables as well as fish or meat, and complement the starchy staples of the main dish, such as pounded yam in the southern part of West Africa or thick porridge made from pearl millet in the drier savannahs in the north. By combining their expertise, archaeology and archaeobotany researchers at Goethe University and chemical scientists from the University of Bristol have corroborated that the origins of such West African dishes date back 3,500 years.

The studies are part of a project funded by the German Research Foundation, which was headed by Professor Peter Breunig and Professor Katharina Neumann and ended in December 2021. For over twelve years, archaeologists and archaeobotanists from Goethe University studied the Nok culture of Central Nigeria, which is known for its large terracotta figures and early iron production in West Africa in the first millennium BC -- although the roots of the Nok culture in fact stretch back to the middle of the second millennium. Research focused above all on the social context in which the sculptures were created, that is, including eating habits and economy. Using carbonised plant remains from Central Nigeria, it was possible to prove that the Nok people grew pearl millet. But whether they also used starchy plants, such as yam, and which dishes they prepared from the pearl millet had so far been a mystery.

"Carbonised plant remains such as seeds and nutshells preserved in archaeological sediments reflect only part of what people ate back then," explains Professor Katharina Neumann. They hoped, she says, that the chemical analyses would deliver additional insights into food preparation. And indeed, with the help of lipid biomarkers and analyses of stable isotopes, the researchers from Bristol were able to show, by examining over 450 prehistoric pots, that the Nok people included different plant species in their diet.

Dr Julie Dunne from the University of Bristol's Organic Geochemistry Unit says: "These unusual and highly complex plant lipid profiles are the most varied seen (globally) in archaeological pottery to date." There appear to be at least seven different lipid profiles in the vessels, which clearly indicates the processing of various plant species and plant organs in these vessels, possibly including underground storage organs (tubers) such as yam.

Since the beginning of the project, the archaeobotanists have sought evidence for the early use of yam. After all, the Nok region is situated in the "yam belt" of West Africa, that is, the area of the continent in which yam is nowadays grown. Carbonised remains are of no further help here because the soft flesh of the tubers is often poorly preserved and mostly non-specific as well. The chemical analyses indicate that -- apart from leaves and other as yet unidentified vegetables -- the Nok people also cooked plant tissue containing suberin. This substance is found in the periderm of both overground and underground plant organs -- possibly a first indication that yam was used, if not the unequivocal proof hoped for.

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Modern humans developed a more effective protection against oxidative stress

Very few proteins in the body have a change that makes them unique compared to the corresponding proteins in Neanderthals and apes. Researchers at the Max Planck Institute for Evolutionary Anthropology in Germany and Karolinska Institutet in Sweden have now studied one such protein, glutathione reductase, which protects against oxidative stress. They show that the risk for inflammatory bowel disease and vascular disease is increased several times in people carrying the Neanderthal variant.

What makes modern humans unique is a question that has eluded researchers for a long time. One way to approach this question is to study the proteins, or building blocks, in the body that have changes that are carried by almost all living people today and occurred after we separated from the ancestors we shared with Neanderthals about 500,000 years ago. There are around 100 proteins that have such a unique change. One of these proteins is glutathione reductase which is part of the body's defense against oxidative stress.

The study, which is published in the journal Science Advances, examines the change in glutathione reductase in detail and was led by Hugo Zeberg at Karolinska Institutet and the Max Planck Institute for Evolutionary Anthropologyand Svante Pääbo at the Max Planck Institute. They show that the Neanderthal protein created more reactive oxygen radicals which are the cause of oxidative stress. It is the third protein change unique to present-day humans that has been studied so far.

The study also shows that the Neanderthal protein has passed over to present-day humans in low frequency when our ancestors mixed with them about 60,000 years ago. Today, it occurs mainly on the Indian subcontinent at an estimated frequency of 1 to 2 per cent of the population. The researchers found that people who carry the Neanderthal protein have a higher risk of developing vascular disease and inflammatory bowel disease, both diseases that are linked to oxidative stress.

"The risk increases we see are large; several times increased risk of inflammatory bowel disease and vascular disease," says Hugo Zeberg.

The researchers can only speculate about why this particular change came to be one of the unique changes that almost all modern humans carry.

"Stopping oxidative stress is a bit like preventing something from rusting. Perhaps the fact that we are living longer has driven these changes," says Svante Pääbo.

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Anthropologists study the energetics of uniquely human subsistence strategies

Among our closest living relatives -- the great apes -- we humans are unique: We have larger brains, reproduce more quickly and have longer life spans. These traits are obviously valuable, but the extra energy required to sustain them is quite significant. So how did we manage to afford them?

A group of anthropologists from UC Santa Barbara, the University of Utah and Duke University have teamed up on a research study to understand the strategies humans developed for obtaining that extra energy. Their findings are published in the current issue of Science.

Evolutionary success is largely determined by the extent to which an organism is effective at extracting energy (i.e. calories) from the environment and converting that energy into offspring. But energy acquisition is constrained by a number of factors, the primary being how much time and energy one can spend in the pursuit of food. Energy budgets represent the balance between energy intake and expenditure that all organisms must navigate in order to survive and reproduce.

"Because energy is such a fundamental currency, evolution has produced many astonishing energy-saving adaptations across the Tree of Life," said Thomas Kraft, the paper's lead author. Currently an assistant professor at the University of Utah, Kraft conducted the research while a postdoctoral student with Michael Gurven, senior author and professor of anthropology at UC Santa Barbara. "But that doesn't mean natural selection always favors reduced energy expenditure. In fact, tremendous variation exists in the 'tempo' of energetic strategies. A dramatic example is the difference between endothermic (warm-blooded) and ectothermic (cold-blooded) animals. Warm-blooded animals tend to use a lot more energy each day but are able to successfully channel that energy into activities that ultimately lead to successful reproduction."

The researchers began by comparing the amount of energy and time humans and other great apes expend in order to obtain all the foods they typically include in their diets. "We studied contemporary subsistence societies of hunter-gatherers and farmers in order to examine the kinds of energetic strategies that have existed for millennia, including those after the advent of plant domestication," said Kraft.

The team of scientists drew especially upon their long-term collective experience working with the Hadza, an indigenous group of foragers in northwest Tanzania, and the Tsimane, an indigenous group of horticulturalists in the Bolivian Amazon.

Compared to chimpanzees, gorillas and orangutans, human hunter-gatherers are not particularly efficient at acquiring food. "It turns out we spend a surprising amount of energy getting food because we walk very long distances and engage in intense activities such as digging tubers or clearing trees," explained Kraft. "Other great apes, in contrast, don't need to go very far each day. Most of their food shopping involves leisurely picking fruit and vegetation."

However, humans do benefit from earning a lot more food energy per hour. While other great apes don't cook their food and they spend exorbitant amounts of time chewing and digesting, humans' high-intensity subsistence activities yield many calories quickly.

"This is like saying that despite the intensity of the work, humans earn a much higher energetic 'salary' than do other apes," said Kraft. "This ability to attain a higher return rate is what makes hunter-gatherers so successful." Add farming to the mix and that rate of return -- or 'salary' -- only increases. "Those who mix farming with foraging double or triple what hunter-gatherers earn," Kraft continued. But high throughput human strategies, which involve expending a lot of energy to get more food faster, can also be quite risky if you fail to get food on a given day. "Yet humans seem uniquely able to overcome this by cooperating and sharing and storing foods to avoid dangerous shortfalls."

Such cooperation has other benefits as well. Being able to meet one's daily food requirement in less time would have provided more opportunities for other endeavors. "Developing the rich social and cultural life so common in all human societies may first have required time-efficient strategies for feeding yourself," said Gurven, who is also director of the UC Santa Barbara's Integrative Anthropological Sciences Unit and co-director of the Tsimane Health and Life History Project.

However, he noted, it also can lead us astray, contributing to health problems such as the current obesity epidemic. "Part of what makes us humans so successful is being really good at figuring out how to get the biggest return for the least effort," Gurven said. "You can see where that leads us today -- driving cars or taking a bus to the local Costco to purchase those tasty $4.99 rotisserie chickens. We've replaced our physical labor in hunting or farming with supply chains. If we evolved to get calories cheaply, then the need to eat less or move more may be a struggle for good reason."

On the other hand, he continued, the research findings suggest humans also evolved to be highly physically active, at least to attain food. "This doesn't mean we need to be vigorously active all the time," he said. "The lesson from subsistence populations is instead to just be less sedentary."

One finding from the study that surprised the researchers involved the high energetic costs of human subsistence strategies. Walking in an upright/bipedal form makes humans move more efficiently than the other great apes, and we use sophisticated tools to make tasks easier to accomplish. However, humans (both hunter-gatherers and farmers) actually expend more energy per day on activities related to acquiring food than do chimpanzees, gorillas and orangutans. This makes our subsistence strategies not very efficient overall.

Anthropology has a long tradition of collecting data on energy flows in different kinds of societies -- e.g. hunter-gatherers, horticulturalists, pastoralists. The researchers compiled these disparate data into a single database so they could ask whether the detailed data they had from the Hadza and the Tsimane were representative of broader patterns in subsistence energetics across societies. And they were, but other surprises came out of this exercise as well.

"We didn't expect that our cross-cultural database would reveal minimal difference in the amount of time spent working between hunter-gatherers and farming populations," he continued. As exemplified by James Suzman's recent book, "Work: A Deep History from the Stone Age to the Age of Robots," many anthropologists have long argued that hunter-gatherers spend very little time working as compared to other human societies. After compiling an exhaustive list of studies, the researchers found no evidence to support the idea that contemporary subsistence farmers spend more time working on average than hunter-gatherers.

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Those earrings are so last year – but the reason you're wearing them is ancient

The necklace, nametag, earrings or uniform you chose to put on this morning might say more than you realize about your social status, job or some other aspect of your identity.

Anthropologists say humans have been doing this -- finding ways to communicate about themselves without the fuss of conversation -- for millennia.

But shell beads recovered from a cave in western Morocco, determined to be between 142,000 and 150,000 years old, suggest that this behavior may go back much farther than previously thought. The finding, detailed Wednesday in the journal Science Advances, was made by a team of archaeologists that includes Steven L. Kuhn, a professor of anthropology in the University of Arizona College of Social and Behavioral Sciences.

The beads, Kuhn and his colleagues say, are the earliest known evidence of a widespread form of nonverbal human communication, and they shed new light on how humans' cognitive abilities and social interactions evolved.

"They were probably part of the way people expressed their identity with their clothing," Kuhn said. "They're the tip of the iceberg for that kind of human trait. They show that it was present even hundreds of thousands of years ago, and that humans were interested in communicating to bigger groups of people than their immediate friends and family."

How does this ancient form of communication show up today? It happens often, Kuhn said.

"You think about how society works -- somebody's tailgating you in traffic, honking their horn and flashing their lights, and you think, 'What's your problem?'" Kuhn said. "But if you see they're wearing a blue uniform and a peaked cap, you realize it's a police officer pulling you over."

Kuhn and an international team of archaeologists recovered the 33 beads between 2014 and 2018 near the mouth of Bizmoune Cave, about 10 miles inland from Essaouira, a city on Morocco's Atlantic coast.

Kuhn co-directs archaeological research at Bizmoune Cave with Abdeljalil Bouzouggar, a professor at the National Institute of Archaeological Sciences and Heritage in Rabat, Morocco, and Phillipe Fernandez, from the University Aix-Marseille in France, who are also authors on the study. El Mehdi Sehasseh, a graduate student at the National Institute of Archaeological Sciences and Heritage, who did the detailed study of the beads, is the study's lead author.

The beads uncovered by Kuhn and his collaborators were made from sea snail shells, and each measures roughly half an inch long. Holes in the center of the beads, as well as other markings from wear and tear, indicate that they were hung on strings or from clothing, Kuhn said.

The beads are like many others found at sites throughout northern and southern Africa, but previous examples date back to no older than 130,000 years. Ancient beads from North Africa are associated with the Aterian, a Middle Stone Age culture known for its distinctive stemmed spear points, whose people hunted gazelles, wildebeest, warthogs and rhinoceros, among other animals.

The beads serve as potential clues for anthropologists studying the evolution of human cognition and communication. Researchers have long been interested in when language appeared. But there was no material record of language until just a few thousand years ago, when humans began writing things down.

The beads, Kuhn said, are essentially a fossilized form of basic communication.

"We don't know what they meant, but they're clearly symbolic objects that were deployed in a way that other people could see them," he said.

The beads are also notable for their lasting form. Rather than painting their bodies or faces with ochre or charcoal, as many people did, the beads' makers made something more permanent, Kuhn said, suggesting the message they intended to convey was a lasting and important one.

In many ways, the beads raise more questions than they answer. Kuhn said he and his colleagues are now interested in learning why the Aterian people felt the need to make the beads when they did. They're exploring several possible explanations. One, Kuhn said, involves a growing population; as more people began occupying North Africa, they may have needed ways to identify themselves.

It is also possible that people in North Africa started using the method of communication at a time when the climate was cold and dry. They may have developed clans or other allegiances to protect limited resources, then perhaps used the beads to express their ethnicity or other identity to show they belonged in a certain area, Kuhn said.

"It's one thing to know that people were capable of making them," Kuhn said, "but then the question becomes, 'OK, what stimulated them to do it?'"

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New evidence supports idea that America’s first civilization was made up of ‘sophisticated’ engineers

The Native Americans who occupied the area known as Poverty Point in northern Louisiana more than 3,000 years ago long have been believed to be simple hunters and gatherers. But new Washington University in St. Louis archaeological findings paint a drastically different picture of America's first civilization.

Far from the simplicity of life sometimes portrayed in anthropology books, these early Indigenous people were highly skilled engineers capable of building massive earthen structures in a matter of months -- possibly even weeks -- that withstood the test of times, the findings show.

"We as a research community -- and population as a whole -- have undervalued native people and their ability to do this work and to do it quickly in the ways they did," said Tristram R. "T.R." Kidder, lead author and the Edward S. and Tedi Macias Professor of Anthropology in Arts & Sciences.

"One of the most remarkable things is that these earthworks have held together for more than 3,000 years with no failure or major erosion. By comparison, modern bridges, highways and dams fail with amazing regularity because building things out of dirt is more complicated than you would think. They really were incredible engineers with very sophisticated technical knowledge."

The findings were published in Southeastern Archaeology on September, 1, 2021. Washington University's Kai Su, Seth B. Grooms, along with graduates Edward R. Henry (Colorado State) and Kelly Ervin (USDA Natural Resources Conservation Service) also contributed to the paper.

The Poverty Point World Heritage site consists of a massive 72-foot-tall earthen mound and concentric half circle ridges. The structures were constructed by hunter-gatherers approximately 3,400 years ago from nearly 2 million cubic yards of soil. Amazingly, this was done without the luxury of modern tools, domesticated animals or even wheeled carts.

According to Kidder, the site was likely an important religious site where Native Americans came in pilgrimage, similar to Mecca. It was abandoned abruptly between 3,000-3,200 years ago -- most likely due to documented flooding in the Mississippi Valley and climate change.

The ridges at Poverty Point contain vast amounts of artifacts around the edges and within, suggesting that people lived there. Kidder and team re-excavated and re-evaluated a site on Ridge West 3 at the Poverty Point Site that was originally excavated by renowned archaeologist Jon Gibson in 1991.

Using modern research methods including radiocarbon dating, microscopic analysis of soils and magnetic measurements of soils, the research provides conclusive evidence that the earthworks were built rapidly. Essentially, there is no evidence of boundaries or signs of weathering between the various levels, which would have occurred if there was even a brief pause in construction. Kidder believes the construction was completed in lifts, or layers of sediment deposited to increase the ridge height and linear dimensions before another layer was placed to expand the footprint vertically and horizontally.

Why does that matter? According to Kidder, the findings challenge previous beliefs about how pre-modern hunters and gatherers behaved. Building the enormous mounds and ridges at Poverty Point would have required a large labor pool that was well organized and would have required leadership to execute. Hunters and gathers were believed to shun politics.

"Between the speed of the excavation and construction, and the quantity of earth being moved, these data show us native people coming to the site and working in concert. This in and of itself is remarkable because hunter-gatherers aren't supposed to be able to do these activities," Kidder said.

What's even more impressive than how quickly the people built the earthen structures is the fact that they're still intact. Due to its proximity to the Gulf of Mexico, this area receives immense amounts of rain that makes earthworks especially prone to erosion. Microscopic analysis of soils shows that the Native Americans mixed different types of soil -- clays, silts and sand -- in a calculated recipe to make the structures stronger.

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Wolves, dogs and dingoes, oh my

 Dogs are generally considered the first domesticated animal, while its ancestor is generally considered to be the wolf, but where the Australian dingo fits into this framework is still debated, according to a retired Penn State anthropologist.

"Indigenous Australians understood that there was something different about the dingoes and the colonial dogs," said Pat Shipman, retired adjunct professor of anthropology, Penn State. "They really are, I think, different animals. They react differently to humans. A lot of genetic and behavioral work has been done with wolves, dogs and dingoes. Dingoes come out somewhere in between."

Wolves, dogs and dingoes are all species of the canidae family and are called canids. In most animals, hybridization between closely related species does not happen, or like female horses and male donkeys, produce mules -- usually non-fertile offspring. However, many canid species, including wolves, dingoes and dogs, can interbreed and produce fertile offspring. Defining species boundaries in canids becomes more difficult.

Domestic dogs came to the Australian continent in 1788 with the first 11 ships of convicts, but dingoes were already there, as were aboriginal Australians who arrived on the continent about 65,000 years ago. A large portion of dingoes in Australia today have domestic dog in their ancestry, but dingoes came to Australia at least 4,000 years ago according to fossil evidence. Shipman believes that date may be even earlier, but no fossils have yet been found.

"Part of the reason I'm so fascinated with dingoes is that if you see a dingo through American eyes you say, 'that's a dog,'" said Shipman. "In evolutionary terms, dingoes give us a glimpse of what started the domestication process."

Shipman reports her analysis of wolves, dogs and dingoes in a January 2021 special issue of the Anatomical Record.

Dingoes, and the closely related New Guinea singing dogs, look like the default definition of dog, but they are not dogs.

"There is a basic doggy look to dingoes," said Shipman.

Genetically and behaviorally they differ from dogs and are more like wolves in their inability to digest starches and their relationships with humans.

Most domestic dogs evolved along with humans as humans became agriculturalists and moved to a diet containing large amounts of starch, whether from maize, rice, potatoes or wheat. Their genome changed to allow the digestion of these starches. Dingoes, like wolves, have very few of the genes for starch digestion.

While indigenous Australians stole dingo puppies from their dens and raised them, these puppies generally left human homes at maturity and went off to breed and raise offspring. The ability to closely bond with humans is limited in dingoes, although present in dogs. Native Australians also did not manipulate dingo breeding, which is a hallmark of domestication.

Dingoes are also well-adapted to the Australian outback and fare well in that environment. Domestic dogs that become feral do not survive well in the outback.

"Aboriginal Australians were not well-regarded as holders of knowledge or special skill when Europeans came to the continent," said Shipman. "So, no one thought to ask them about dingoes. Even recently, asking aboriginals for their scientific or behavioral knowledge really was not common."

However, aboriginal Australians have a long history of living with dingoes in their lives. Many people argue that dingoes are just dogs -- strange dogs, but just dogs, said Shipman. But, according to aboriginals, dingoes are not dogs.

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Why independent cultures think alike when it comes to categories: It's not in the brain

 Imagine you gave the exact same art pieces to two different groups of people and asked them to curate an art show. The art is radical and new. The groups never speak with one another, and they organize and plan all the installations independently. On opening night, imagine your surprise when the two art shows are nearly identical. How did these groups categorize and organize all the art the same way when they never spoke with one another?

The dominant hypothesis is that people are born with categories already in their brains, but a study from the Network Dynamics Group (NDG) at the Annenberg School for Communication has discovered a novel explanation. In an experiment in which people were asked to categorize unfamiliar shapes, individuals and small groups created many different unique categorization systems while large groups created systems nearly identical to one another.

"If people are all born seeing the world the same way, we would not observe so many differences in how individuals organize things," says senior author Damon Centola, Professor of Communication, Sociology, and Engineering at the University of Pennsylvania. "But this raises a big scientific puzzle. If people are so different, why do anthropologists find the same categories, for instance for shapes, colors, and emotions, arising independently in many different cultures? Where do these categories come from and why is there so much similarity across independent populations?"

To answer this question, the researchers assigned participants to various sized groups, ranging from 1 to 50, and then asked them to play an online game in which they were shown unfamiliar shapes that they then had to categorize in a meaningful way. All of the small groups invented wildly different ways of categorizing the shapes. Yet, when large groups were left to their own devices, each one independently invented a nearly identical category system.

"If I assign an individual to a small group, they are much more likely to arrive at a category system that is very idiosyncratic and specific to them," says lead author and Annenberg alum Douglas Guilbeault (Ph.D. '20), now an Assistant Professor at the Haas School of Business at the University of California, Berkeley. "But if I assign that same individual to a large group, I can predict the category system that they will end up creating, regardless of whatever unique viewpoint that person happens to bring to the table."

"Even though we predicted it," Centola adds, "I was nevertheless stunned to see it really happen. This result challenges many long -- held ideas about culture and how it forms."

The explanation is connected to previous work conducted by the NDG on tipping points and how people interact within networks. As options are suggested within a network, certain ones begin to be reinforced as they are repeated through individuals' interactions with one another, and eventually a particular idea has enough traction to take over and become dominant. This only applies to large enough networks, but according to Centola, even just 50 people is enough to see this phenomenon occur.

Centola and Guilbeault say they plan to build on their findings and apply them to a variety of real -- world problems. One current study involves content moderation on Facebook and Twitter. Can the process of categorizing free speech versus hate speech (and thus what should be allowed versus removed) be improved if done in networks rather than by solitary individuals? Another current study is investigating how to use network interactions among physicians and other health care professionals to decrease the likelihood that patients will be incorrectly diagnosed or treated due to prejudice or bias, like racism or sexism. These topics are explored in Centola's forthcoming book, CHANGE: How to Make Big Things Happen (Little, Brown & Co., 2021).

"Many of the worst social problems reappear in every culture, which leads some to believe these problems are intrinsic to the human condition," says Centola. "Our research shows that these problems are intrinsic to the social experiences humans have, not necessarily to humans themselves. If we can alter that social experience, we can change the way people organize things, and address some of the world's greatest problems."

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New approach to some mental disorders

Some of the most common mental disorders, including depression, anxiety and PTSD, might not be disorders at all, according to a recent paper by Washington State University biological anthropologists.

In the paper, published in the Yearbook of Physical Anthropology, the researchers propose a new approach to mental illness that would be informed by human evolution, noting that modern psychology, and in particular its use of drugs like antidepressants, has largely failed to reduce the prevalence of mental disorders. (This paper was made available online on Nov. 28, 2019 ahead of final publication in the issue on April 28, 2020). For example, the global prevalence of major depressive disorder and anxiety disorders remained steady at 4.4% and 4% respectively from 1990 to 2010.

The authors also theorize that depression, anxiety and post-traumatic stress disorder may be primarily responses to adversity; therefore, only treating the "psychic pain" of these issues with drugs will not solve the underlying problem. Kristen Syme, the first author on the paper and recent WSU Ph.D. graduate, compared it to medicating someone for a broken bone without setting the bone itself.

"The pain is not the disease; the pain is the function that is telling you there is a problem," said Syme. "Depression, anxiety and PTSD often involve a threat or exposure to violence, which are predictable sources for these things that we call mental diseases. Instead, they look more like sociocultural phenomena, so the solution is not necessarily fixing a dysfunction in the person's brain but fixing dysfunctions in the social world."

Syme and co-author Edward Hagen advocate for biological anthropologists to enter the study of the "diseases of the mind," to help find effective solutions, particularly for some problems that may be social instead of mental.

"Mental health research is still very much stuck in a view that comes out of the 19th century, and revived in 1980, of classifying everything by symptoms in the hopes of revealing underlying patterns that would lead to solutions, but it really has not," said Hagen, a WSU professor of evolutionary anthropology and corresponding author on the paper. "Even though we're using new measurements, like genetics, biomarkers and imaging, these still haven't added up to the insights needed to really improve people's lives."

Among the more problematic issues, the researchers point to the "chemical imbalance" theory of depression, which has helped create a boom in antidepressant drugs meant to modulate certain chemicals in the brain called neurotransmitters. A large meta-analysis of antidepressant trials in 2018 found that antidepressants had almost the same effect as a placebo, and their widespread use has not delivered measurable results. For example, in Australia alone, antidepressant use increased 352% from 1990 to 2002, yet there has been no observed reduction in the prevalence of mood, anxiety or substance use disorders in any country.

Instead of addressing mental issues by their symptoms, Hagen and Syme propose approaching mental illness by their probable causes. They acknowledge that some psychiatric disorders like schizophrenia are likely genetic and often inherited and others like Alzheimer's appear connected with aging.

However, the anthropologists argue that some conditions might be a mismatch between modern and ancestral environments such as attention-deficit/hyperactivity disorder, also known as ADHD. Hagen pointed out that there is little in our evolutionary history that accounts for children sitting at desks quietly while watching a teacher do math equations at a board.

Other disorders such as depression, anxiety and PTSD are not hereditary, occur at any age and are often tied to threatening experiences. Hagen and Syme propose they may be responses to adversity and serve as signals, much like physical pain does, to make people aware of the need for help.

These conditions also disproportionately affect people in developing countries. For instance, 1 in 5 people in conflict-affected countries suffer from depression versus 1 in 14 in worldwide.

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Disappearance of animal species takes mental, cultural and material toll on humans

For thousands of years, indigenous hunting societies have subsisted on specific animals for their survival. How have these hunter-gatherers been affected when these animals migrate or go extinct?

To answer this and other questions, Tel Aviv University (TAU) researchers conducted a broad survey of several hunter-gatherer societies across history in a retrospective study published on January 30 in Time and Mind. The study, led by Eyal Halfon and Prof. Ran Barkai of TAU's Department of Archeology and Ancient Near Eastern Cultures, sheds new light on the deep, multidimensional connection between humans and animals.

"There has been much discussion of the impact of people on the disappearance of animal species, mostly through hunting," explains Halfon. "But we flipped the issue to discover how the disappearance of animals -- either through extinction or migration -- has affected people."

The research reveals that these societies expressed a deep emotional and psychological connection with the animal species they hunted, especially after their disappearance. The study will help anthropologists and others understand the profound environmental changes taking place in our own lifetimes.

Halfon and Prof. Barkai conducted a survey of different historical periods and geographical locations, focusing on hunter-gatherer societies that hunted animals as the basis for their subsistence. They also investigated situations in which these animals became extinct or moved to more hospitable regions as a result of climate change.

"We found that humans reacted to the loss of the animal they hunted -- a significant partner in deep, varied and fundamental ways," Halfon says.

The new research explores hunter-gatherer societies throughout human history, from those dating back hundreds of thousands of years to modern-day societies that still function much the way prehistoric groups did. Ten case studies illustrate the deep connection -- existential, physical, spiritual and emotional -- between humans and animals they hunted.

"Many hunter-gatherer populations were based on one type of animal that provided many necessities such as food, clothing, tools and fuel," Prof. Barkai says. "For example, until 400,000 years ago prehistoric humans in Israel hunted elephants. Up to 40,000 years ago, residents of Northern Siberia hunted the woolly mammoth. When these animals disappeared from those areas, this had major ramifications for humans, who needed to respond and adapt to a new situation. Some had to completely change their way of life to survive."

According to the study, human groups adapted in different ways. Siberian residents seeking sustenance after the disappearance of mammoths migrated east and became the first settlers of Alaska and northern Canada. Cave dwellers in central Israel's Qesem Cave (excavated by Prof. Barkai) hunted fallow deer, far smaller than elephants, which required agility and social connections instead of robust physical strength. This necessitated far-reaching changes in their material and social culture and, subsequently, physical structure.

Halfon stresses the emotional reaction to an animal group's disappearance. "Humans felt deeply connected to the animals they hunted, considering them partners in nature, and appreciating them for the livelihood and sustenance they provided," he says. "We believe they never forgot these animals -- even long after they disappeared from the landscape."

An intriguing example of this kind of memory can be found in engravings from the Late Paleolithic period in Europe, which feature animals like mammoths and seals. Studies show that most of these depictions were created long after these two animals disappeared from the vicinity.

"These depictions reflect a simple human emotion we all know very well: longing," says Halfon. "Early humans remembered the animals that disappeared and perpetuated them, just like a poet who writes a song about his beloved who left him."

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How Human Population came from our ability to cooperate

Humans may owe their place as Earth's dominating species to their ability to share and cooperate with each other, according to a new study published in the Journal of Anthropological Research.

In "How There Got to Be So Many of Us: The Evolutionary Story of Population Growth and a Life History of Cooperation," Karen L. Kramer explores the deep past to discover the biological and social underpinnings that allowed humans to excel as reproducers and survivors. She argues that the human tendency to bear many children, engage in food sharing, division of labor, and cooperative childcare duties, sets us apart from our closest evolutionary counterparts, the apes.

In terms of population numbers, few species can compare to the success of humans. Though much attention on population size focuses on the past 200 years, humans were incredibly successful even before the industrial revolution, populating all of the world's environments with more than a billion people. Kramer uses her research on Maya agriculturalists of Mexico's Yucatan Peninsula and the Savanna Pumé hunter-gatherers of Venezuela to illustrate how cooperative childrearing increases the number of children that mothers can successfully raise and -- in environments where beneficial -- even speed up maturation and childbearing. Kramer argues that intergenerational cooperation, meaning that adults help support children, but children also share food and many other resources with their parents and other siblings, is at the center of humans' demographic success. "Together our diet and life history, coupled with an ability to cooperate, made us really good at getting food on the table, reproducing, and surviving," Kramer writes.

During her time with the Maya, Kramer constructed a demographic model that considered how much household members consume, as the family grows and matures across a mother's reproductive career, balanced against how much a mother, father, and their children contribute. She found that Maya children contributed a substantial amount of work to the family's survival, with those aged 7-14 spending on average 2 to 5 hours working each day, and children aged 15-18 spending as much as their parents, about 6.5 hours a day. Labor type varied, with younger children doing much of the childcare, older children and fathers fill in much of the day-today cost of growing and processing food and running the household. "If mothers and juveniles did not cooperate, mothers could support far fewer children over their reproductive careers," Kramer writes. "It is the strength of intergenerational cooperation that allows parents to raise more children than they would otherwise be able to on their efforts alone."

Kramer's second research population were the Savanna Pumé, hunter-gatherers in west-central Venezuela. The Savanna Pumé live in a high-mortality environment, with challenges such as seasonal undernutrition, high immunological stress, chronic intestinal parasite loads, endemic malaria, and no access to healthcare or immunization. Despite all this -- or perhaps, in part, because of it -- Savanna Pumé girls mature quickly and begin childbearing in their mid-teens. This pattern conforms with theoretic predictions that fast maturation optimizes fitness in a high-mortality environment. Early childbearing is also, however, associated with a higher probability of mothers losing their firstborn.

Kramer found that intergenerational cooperation mitigated these risks. "In this challenging environment, young Pumé females are buffered against seasonal fluctuations because food is shared with them, she writes. "If young Pumé mothers relied solely on their own efforts, they would have to delay childbearing until they matured as foragers and caretakers.

Humans' ability to reproduce more successfully than other great apes can be traced to differences in evolutionary strategy: humans bear more children, at a faster rate. They also provision food for juveniles, whereas other great apes stop helping children find food as soon as they have been weaned. Humans are able to shoulder the greater childcare burden through cooperation.

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Preserving old bones with modern technology

A team of University of Colorado Boulder anthropologists is out to change the way that scientists study old bones damage-free.

If that sounds like a macabre goal, consider this: Bits of well-preserved bones are valuable to researchers studying humans who lived thousands to hundreds of thousands of years ago.

These samples sometimes contain collagen, a useful molecule than can reveal a wealth of information about human remains -- from how long ago a person died to what he or she may have eaten.

"Bone collagen is really a treasure within the realm of archaeology," said Christina Ryder, a graduate student in the Department of Anthropology at CU Boulder.

Now, she and her colleagues have come up with a creative way to be thrifty with that treasure.

In research published this week in the journal Scientific Reports, the group describes a new method for screening bone samples to see if they contain collagen. Unlike existing tools that look for that type of tissue, the team's approach won't damage the bones in the process.

For anthropologists, the test could be "a game changer," said study coauthor Matt Sponheimer, a professor of anthropology at CU Boulder.

"These remains have lain intact for thousands of years, so it always hurts a little bit to destroy a sample," he said. "It's doubly tragic if you do it, and it's all in vain. That's what we're trying to prevent."

It's a goal that emerged out of many hours of frustration. Several years ago, one of Sponheimer's colleagues was tasked with extracting collagen from a series of ancient bone samples. Collagen within bones is a bit like a birth certificate; if scientists can find enough of it, they can use collagen to determine the age of a human specimen through radiocarbon dating.

But this material, which helps to hold together human bones and other tissue, also doesn't age well. Many skeletal remains, even those from well-preserved graves, don't contain much of it.

"My student was spending weeks and, ultimately, months of lab time trying to get dietary info from ancient collagen, and it was working incredibly poorly," Sponheimer said. "I thought to myself, 'There has to be a better way.'"

As it turns out, there was. In their latest study, Sponheimer, Ryder and their colleagues discovered that they could calibrate a machine called a near-infrared spectrometer to test bones for the presence of collagen.

The process is surprisingly easy, Ryder said. The instrument, which operates by way of a handheld probe, scans samples of bone and then -- in a matter of seconds -- churns out an estimate of how much collagen is inside.

"I'll tease that the longest part of the process is typing in the file name," Ryder said.

To make sure that their method was accurate, the researchers tested their instrument on more than 50 samples of ground-up bone with known concentrations of collagen. The tests correctly predicted the approximate concentrations of collagen within each of those samples. It worked with 44 pieces of whole bone, too.

Ryder added that the entire spectrometer is about the size of a briefcase, which means that the team can carry it with them into the field.

It's already gone through one high-profile dry run. Last year, Ryder flew to Germany to meet with colleagues at the Max Planck Institute for Evolutionary Anthropology. The researchers wanted to date human remains uncovered from Dolni Vestonice -- a one-of-a-kind archaeological site in the Czech Republic that hosts some of the oldest known examples of representational art in human history.

"The grad student on this project had only six vials of samples from human burials," Ryder said. "That was all she had, and that was all anyone was going to have for the foreseeable future."

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Bonobo mothers help their sons to have more offspring

Bonobos.

In many social animal species individuals share child-rearing duties, but new research from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, finds that bonobo mothers go the extra step and actually take action to ensure their sons will become fathers. This way bonobo mothers increase their sons' chance of fatherhood three-fold.

"This is the first time that we can show the impact of the mother's presence on a very important male fitness trait, which is their fertility," says Martin Surbeck, a primatologist at the Max Planck Institute for Evolutionary Anthropology. "We were surprised to see that the mothers have such a strong, direct influence on the number of grandchildren they get."

Surbeck and his colleagues observed wild populations of bonobos in the Democratic Republic of Congo, as well as wild populations of chimpanzees in Ivory Coast, Tanzania, and Uganda. They found that while both bonobo and chimpanzee mothers would advocate for their sons in male-on-male conflicts, bonobo moms went the extra mile to aid their sons' copulation efforts. This involved protecting their sons' mating attempts from other males and intervening in other male's mating attempts.

The bonobo mothers were also able to use their rank in the bonobo's matriarchal society to give their sons access to popular spots within social groups in the community and help them achieve higher male status -- and therefore, better mating opportunities. The authors note that these interactions were rare in chimpanzee societies and did not have an effect on male fertility; in chimpanzees males hold dominant positions over females, making the actions of chimp mothers less influential than those of bonobo mothers.

Interestingly, bonobo moms did not extend similar help to their daughters, nor were there any observations of daughters receiving assistance in rearing their offspring. "In bonobo social systems, the daughters disperse from the native community and the sons stay," Surbeck says. "And for the few daughters that stay in the community, which we don't have many examples of, we don't see them receiving much help from their mothers."

Moving forward, Surbeck and his team would like to better understand the benefits these behaviors confer on bonobo mothers. Currently, they think that it allows for an indirect continuation of their genes. "These females have found a way to increase their reproductive success without having more offspring themselves," he says, noting that the prolongation of the post-reproductive human female lifespan, as well as the early-age at which human women can no longer bare children, may have evolved from this indirect method of continuing their genetic line.

Surbeck acknowledges that gathering data on post-reproductive lifespans of females in chimp and bonobo communities will require a long-term, collaborative study, similar to this one. "Without the help and participation from all of the field sites where data was collected, these important interactions could have been overlooked," he says. "Now as the director of a bonobo field site, I'm looking forward to further exploring this topic."

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