Enormous stone statues, called moai, on Easter Island

What’s the News: Easter Island is often held up as an example of what can happen when human profligacy and population outpace ecology: Wanton deforestation led to soil erosion and famine, the story goes, and the islanders’ society declined into chaos and cannibalism. But through their research on Easter Island, paleoecologists Terry Hunt and Carl Lipo have unearthed evidence that contradicts this version of events. The Polynesian settlers of Easter Island prospered through careful use of the scant available resources, they argue in their new book The Statues That Walked; the island’s forests were done in not by greedy humans, but by hungry rats.

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We know the Bering land bridge that appeared between Alaska and Russia at least 14,000 years ago would have allowed ancient people to cross over into America. But what were those people like? Scant evidence has turned up to reveal their lifestyle, but in the journal Science this week archaeologists report a new find—one that’s simultaneously insightful and a portrait of sadness. Ben Potter and colleagues found an 11,500-year-old house that was apparently the scene of the loss of a child, as the fire pit shows the skeletal remains of a person about three years of age.

The bones are the oldest human remains yet discovered in northern North America, and provide a remarkable glimpse into the lives of the earliest North American settlers…. Older human remains and temporary hunting camps and work sites have been found, but longer-term habitations are rare. Yet the child’s young age – it was about 3 years old – and the type of food remains found at the new site, suggest it was the summer home for a group that comprised at least women and young children. [New Scientist]

The place is called Upper Sun River, located in central Alaska. The child has been given the name Xaasaa Cheege Ts’eniin, or “Upward Sun River Mouth Child.”

Potter … and his colleagues discovered the outlines of the foundation of a circular house, including a scattering of stone tools and animal bones on the floor and traces of posts that may have held up the walls and roof. As the team reports in this week’s issue of Science, the center of the house was taken up with a large circular pit containing the fragmented, partially burnt bones of the child. [ScienceNOW]

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Early humans trekking out of Africa moved faster than we thought they did: New archeological evidence suggests they reached the Persian Gulf 50,000 years before we previously thought.

Archeologists excavating a rock shelter in Jebel Faya, in the United Arab Emirates, found a cache of hand axes and other tools that date back 125,000 years ago. Their age was established by dating the silicon in the chert tools, and also via comparison to other artifacts:

Team member Anthony Marks of Southern Methodist University, an anthropologist, said the tools were made in ways consistent with the 125,000-years-ago time period and therefore raise the inevitable question of how they got to the area near the Persian Gulf…. “Either these people came out of East Africa or they came from nowhere,” he said. [The Washington Post]

The team’s research, published in Science, posits that the area’s climate had a role in spurring mankind’s expansion around the planet. Climate records suggest that the Red Sea was much shallower during an ice age that lasted from 200,000 to 130,000 years ago, because much of the world’s water was trapped in glaciers. This allowed early humans to cross the now-shallow Red Sea for new land in the southern Arabian peninsula, the researchers say. After the crossing, these early humans would have found themselves in a surprisingly fertile place: Towards the end of that ice age, the deserts of Arabia experienced a brief “wet” era with rivers, lakes, vegetation, and wildlife.

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The “cradle of humanity” is thought to be located in Sub-Saharan Africa–meaning below the Sahara, the largest hot desert on earth. So how was humanity able to breach such an intimidating barrier to spread out across the rest of the world?

Until now, anthropologists typically argued that hominids could only have followed the lush Nile River valley north in order to reach the Middle East and beyond. But new research is suggesting that the Sahara might not have been an impassable barrier to those humans after all. Some animals (including several fish species) are found on both the north and south sides of the desert, and even in some safe-haven ponds in between. The researchers argue that if these ancestral fish could swim across the region that we now know as the Sahara, humans could have also made it across.

“Fish appeared to have swam across the Sahara during its last wet phase sometime between 10,000 and 6,000 years ago,” researcher Nick Drake, a geographer at King’s College London, told LiveScience. “The Sahara is not a barrier to the migrations of animals and people. Thus it is possible–likely?–that early modern humans did so, and this could explain how we got out of Africa.” [LiveScience]

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Every time governments fail to take serious steps on climate change, it seems the parlor game of predicting what our warmer world will look like heats up. And the newest of those predictions, appearing this week in the Proceedings of the National Academy of Sciences, pokes at what is presently one of the country’s most sensitive spots: immigration.

Michael Oppenheimer of Princeton published a study that estimates that between 1.4 and 6.7 million people could become climate refugees emigrating from rural Mexico to the United States between now and 2080. That’s 2 to 10 percent of the present Mexican population, and it doesn’t include people who would make the move for other reasons.

Is it a major concern? Yes. How much stock should you put in those statistics? Not much.

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It makes sense: stay where it’s warm, sunny, and there’s a lot of food. What, then, were prehistoric people doing on the British seashore? New research published today in Nature pushes human arrival in Britain back to about 800,000 years ago, roughly 100,000 years earlier than our previous estimations. The evidence? A trove of 70 flint tools found on the Happisburgh shore in Norfolk.

Dating artifacts that old isn’t easy (for example, carbon dating doesn’t work), so the researchers had to be thorough. Led by Simon A. Parfitt of The Natural History Museum in London and Nick Ashton of the British Museum, London as part of the Ancient Human Occupation of Britain project, the team used both biological and physical evidence to date the tools. Looking at insect and plant fossils found with the artifacts, researchers determined that the species dated back to the Early Pleistocence period, between 990,000 and 780,000 years ago. The researchers also tested sediment around the tools, and established that they were buried when the Earth’s magnetic field was flipped. The last time this happened was also about 780,000 years ago.

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Three jaw-less heads and one really old shoe. These aren’t the clues in a Law and Order episode; they’re findings from a limestone cave in Armenia. As described in a paper published yesterday in PLoS ONE, archaeologists believe they have found the world’s oldest leather shoe: it’s 5,500 years old.

“It’s pretty weird,” said lead author Ron Pinhasi to CNN regarding the disembodied heads and the placement of the well-preserved shoe. The ancient sneaker was stuffed with grass, though archaeologists can’t say whether the grass was intended as insulation or whether it helped maintain the shoe’s shape.

“We thought originally it could be a discard, but at the same time, it’s very strange, because we have only one shoe, and it’s in very good shape,” Pinhasi said. “It looks like it was more than likely deliberately placed in this way.” [CNN]

The right-footed shoe–which looks a bit like a baked potato–has some features that might entice even modern buyers: for one, its maker fashioned it from a single piece of cow leather (like a pricey pair of today’s “whole cut” footwear), and it has leather laces. It’s about a women’s size seven, but, researchers say, it might have graced a small-footed man.

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Just how connected are the Jews, genetically speaking? Despite the fact that pockets of Jewish people are spread around the globe, the new genetic analysis by Harry Ostrer and his team says that they share genetic markers that go back thousands of years.

In the study in the American Journal of Human Genetics, Ostrer investigated Jewish people from all over the world:

Historians divide the world’s 13 million living Jews into three groups: Middle Eastern, or Oriental, Jews; Sephardic Jews from Spain and Portugal; and Ashkenazi Jews from Europe [ScienceNOW].

Taking nuclear DNA samples from 237 Jews—some from each group—the team compared them to samples from more than 400 non-Jewish people who lived in the same regions.

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Ever since anthropologists figured out that early humans and Neanderthals coexisted for a span of prehistory, they’ve wondered–did the two species, you know, make friends? Now a fascinating new genetics study reveals that Homo sapiens and Neanderthals did indeed interbreed, and the evidence is still to be found in the human genome.

Researchers from Germany’s Max Planck Institute for Evolutionary Anthropology first sequenced the entire Neanderthal genome from powdered bone fragments found in Europe and dating from 40,000 years ago–a marvelous accomplishment in itself. Then, they compared the Neanderthal genome to that of five modern humans, including Africans, Europeans, and Asians. The researchers found that between 1 percent and 4 percent of the DNA in modern Europeans and Asians was inherited from Neanderthals, which suggests that the interbreeding took place after the first groups of humans left Africa.

Anthropologists have long speculated that early humans may have mated with Neanderthals, but the latest study provides the strongest evidence so far, suggesting that such encounters took place around 60,000 years ago in the Fertile Crescent region of the Middle East [The Guardian].

The study, published in Science and made available to the public for free, opens up new areas for research. Geneticists will now probe the function of the Neanderthal genes that humans have hung on to, and can also look for human genes that may have given us a competitive edge over Neanderthals.

Erik Trinkaus, an anthropologist at Washington University in St. Louis, who has long argued that Neanderthals contributed to the human genome, welcomed the study, commenting that now researchers “can get on to other things than who was having sex with who in the Pleistocene” [AP].

For a much deeper dive into these issues, head to Carl Zimmer’s post at The Loom and Razib Khan’s post at Gene Expression.

Related Content:
The Loom: Skull Caps and Genomes
Gene Expression: Breaking: There’s a Little Bit of Neandertal in All of Us
80beats: We May Soon Be Able to Clone Neanderthals. But Should We?
80beats: Crafty & Clever Neanderthals Made Jewelry 50,000 Years Ago
80beats: Did Spear-Throwing Humans Kill Neanderthals?
80beats: Rough Draft of the Neanderthal Genome is Complete!
DISCOVER: Works in Progress asks whether we rubbed out Neanderthals, or rubbed off on them

Image: Max Planck Institute EVA. The researchers hang out with their Neanderthal relation.

In 2008, archeologists working at the Denisova Cave in Siberia’s Altai Mountains discovered a tiny piece of a finger bone, believed to be a pinky, buried with ornaments in the cave. Scientists extracted the mitochondrial DNA (genetic material from the mother’s side) from the ancient bone and checked to see if its genetic code matched with the other two known forms of early hominids–Neanderthals and the ancestors of modern humans. What they found was a real surprise. The team, led by geneticist Svaante Paabo of the Max Planck Institute, discovered that the mtDNA from the finger bone matched neither–suggesting there might have been an entirely different hominid species that roamed the planet about 50,000 years ago.

Looking back at the region and the cave, where scientists earlier discovered artifacts from humans and Neanderthals, Paabo thinks that it is possible that all the three species (modern humans, Neanderthals and the mystery hominids) could have possibly met and interacted with each other. The findings, which were published in journal Nature, present an unexpected twist in the story of human evolution and migration.

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Have you seen this man? Probably not: He lived 4,000 years ago.

The image to the left is not a wanted poster, but rather an artist’s impression of Inuk, the name given to him by the scientists who sequenced his genome. It’s the first time the genetic code of an ancient human has been deciphered this completely, and the researchers published their results this week in Nature.

Inuk died on an island off Greenland called Qeqertasussuk. Researchers don’t know the cause of death, but they do know he left bits of hair and bone that the permafrost preserved. Scientists found the thick clumps of hair—which could be the remnants of a 4,000-year-old haircut—in the 1980s, and stored them in the National Museum of Denmark. Today’s DNA sequencing technology allowed them to look back in time at what he may have been like. Inuk’s genes reveal he was a fairly young man, robustly built to exist in a frigid climate, with A-positive blood, dark skin, brown eyes, and thick, black hair on a scalp genetically susceptible to baldness [San Francisco Chronicle].

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A clever and painstaking new analysis has revealed that the famous Homo erectus fossil known as Peking Man is 200,000 years older than previously thought. The fossil, discovered almost a century ago during excavations of the Zhoukoudian caves near Beijing, is now thought to be about 750,000 years old. The revised date could change the timeline and number of migrations of the Homo erectus species out of Africa and into Asia [LiveScience]. 

Homo erectus were the first hominids to leave the evolutionary cradle of Africa. The species had a distinctive barrel-shaped torso and stood [57 to 70 inches] tall, walking upright in a similar way to modern humans [Nature News]. Researchers had previously suggested that one wave of Homo erectus wayfarers migrated out of Africa between 2 million and 1.6 million years ago, settling Indonesia and southern Asia first before moving northward. But new fossil discoveries, coupled with the new dating of Peking Man, are forcing paleoanthropologists to rethink this scenario.

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The spit in each person’s mouth contains a diverse and unique universe of bacteria, according to a study in the journal Genome Research, and there’s no geographical pattern to the differences between one mouth and the next. A new worldwide survey of the human saliva microbiome – the bugs in our spit – finds that a man from La Paz, Bolivia, shares no more microbes in common with his neighbours than with a woman from Shanghai [New Scientist].

Molecular anthropologist Mark Stoneking made the discovery while searching for a better way to trace prehistoric human migrations. He had been impressed by how anthropologists were able to trace human migrations through the differences in the strains of the stomach bug Helicobacter pylori in various groups of people…. “With that species, you see very strong geographic patterning,” says Stoneking. But getting a sample of H. pylori is relatively difficult, as it requires a stomach biopsy. He wondered whether any of the bacteria in spit would work instead [ScienceNOW Daily News].

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The tools found in Colorado resident Patrick Mahaffy’s backyard weren’t the typical collection of weed whackers and shovels. Instead Mahaffy’s yard hosted a collection of chipped stone knives and axes that date from the time of the Clovis people, who are believed to have been among the first inhabitants of America around 13,000 years ago. “The idea that these Clovis-age tools essentially fell out of someone’s yard in Boulder is astonishing,” [anthropologist Douglas Bamforth] said. “But the evidence I’ve seen gives me no reason to believe the cache has been disturbed since the items were placed there for storage about 13,000 years ago” [LiveScience].

The prehistoric tool cache was turned up when landscapers were digging a hole for a fishpond in Mahaffy’s backyard, and struck stone. The collection contains 83 knives, axes, and smaller pieces of flint, and a chemical analysis of blood residue left on the blades revealed that the tools had been used to butcher extinct types of North American camels and horses, and well as bears and sheep.

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Two groups of researchers seem to have solved the mystery of how and when the first human settlers spread out through the Pacific Islands. One group studied the evolution of a stomach bacteria while the other examined the evolution of language, but both came up with remarkably congruous results. The evolutionary trajectory implied by words and bugs begins with an initial migration from Taiwan 5,000 years ago, with a first wave of people spreading to the Philippines and a second to western Polynesia [Wired News].

In the bacterial study, researchers took stomach samples from people native to Taiwan, Australia, Melanesia, Polynesia and New Guinea. They measured genetic variation in Helicobacter pylori, a common gut microbe that traveled with humans when they first left Africa more than 60,000 years ago…. They found that the [bacteria] from people’s guts in Polynesia and Melanesia–islands stretching from New Caledonia all the way to Samoa–were genetically similar to the samples from aboriginal people in Taiwan. What’s more, the Taiwanese bacteria had more genetic diversity than other populations [The Scientist]. Because genetic mutations accumulate over time, these results indicate that the early Taiwanese people were the ancestors of the other groups that split off over the centuries.

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