A people who may have been ancestors of the first Americans lived in Arctic Siberia, enduring one of the most unforgiving environments on Earth at the height of the Ice Age, according to researchers who discovered the oldest evidence yet of humans living near the frigid gateway to the New World.
Russian scientists uncovered a 30,000-year-old site where ancient hunters lived on the Yana River in Siberia, 300 miles (480 kilometers) north of the Arctic Circle and not far from the Bering land bridge that then connected Asia with North America.
"Although a direct connection remains tenuous, the Yana ... site indicates that humans extended deep into the Arctic during colder (Ice Age) times," the authors wrote in a study appearing this week in the journal Science.
The researchers found stone tools, ivory weapons and the butchered bones of mammoths, bison, bear, lion and hare, all animals that would have been available to hunters during that Ice Age period.
Using a dating technique that measures the ratios of carbon, the researchers determined the artifacts were deposited at the site about 30,000 years before the present. That would be about twice as old as Monte Verde in Chile, the most ancient human life known in the American continents.
Donald Grayson, a paleoanthropologist at the University of Washington in Seattle, said the discovery is very significant because it is so much earlier than any other proven evidence of people living in the frigid lands of Siberia that formed the gateway to the Americas.
"Until this site was reported, the earliest site in Bering land bridge area was dated at about 11,000 years ago," Grayson said. "Every other site that had been thought to have been early enough to have something to do with peopling of the New World has been shown not to be so."
At the time of the Yana occupation, much of the high latitudes on the Earth were in the grip of an ice age that sent glaciers creeping over much of what is now Europe, Canada and the northern United States.
But the Yana River area was ice-free, a dry flood plain without glaciers. It was home to mammoth, horse, musk ox and other animals that provided food for the human hunters who braved Arctic blasts to live there.
"Abundant game means lots of food," Julie Brigham-Grette of the University of Massachusetts, Amherst, said in Science. "It was not stark tundra as one might imagine."
Among the artifacts found at the Yana site were weapons that resembled some found at a Clovis, N.M., site dated around 11,000 years old. But Grayson and others said the evidence is weak linking those implements to the tool and weapon techniques used by the Clovis people. Similar artifacts have also been found in Europe and western Asia, Grayson said.
"The similarities (in the tools and weapons) are not enough to prove they were ancestral to the Clovis people in the New World," said Grayson.
Some experts, however, still hold out hope that the new discovery provides important new clues about the ancient migration from Asia to the Americas.
Finding evidence of human habitation at the Yana site "makes it plausible that the first peopling of the Americas occurred prior to the last glacial maximum," Daniel Mann of the University of Alaska, Fairbanks, said in Science. The last glacial maximum was 20,000 to 25,000 years ago.
More evidence needed
Grayson and others, however, said more evidence is needed before it becomes widely accepted that it was people from the Yana site who migrated to the New World.
The major problem, said Grayson, is that archaeological evidence for human dwellings in Siberia is still very sparse. Also, there is a gap of thousands of years between the 30,000-year-old Yana site and other sites in Asia and the Americas.
There was no physical barrier to going to the Americas from Asia during that period. The Bering land bridge connected the two continents until about 11,000 years ago, when a rising sea level flooded the connection and created what is now called the Bering Strait between Russia and Alaska.
"Getting people across to the New World was not the problem," said Grayson. "The problem was getting people into that part of the world so they could cross."
And the evidence that this happened from the Yana site, he said, is still unpersuasive.