While the story of Homo sapiens begins about 2.5 million years ago in sunny Africa, there has been no evidence that early humans ventured into bitter subarctic regions, such as northern Siberia, until at most 30,000 years ago. But new dating of a site on Siberia's Lena River, reported in tomorrow's issue of Science,* would push the occupation of northern Siberia about 10 times further back, to more than 260,000 years ago. It "puts humans in the far north way earlier than anyone had anticipated," says archaeologist Rob Bonnichsen of Oregon State University in Corvallis.
The evidence comes from a site called Diring Yuriakh which has been the subject of a sprawling excavation by Russian archeologist Yuri Mochanov since its discovery in 1982. About 4000 artifacts have been uncovered, including many simple choppers and scrapers arrayed around rocks that archeologists believe were used as anvils to break the stones, probably to cut up animals and fish.
With no bones or other organic artifacts to go on, dating was chancy. Mochanov has argued--in part because the tools resemble those from more than 2 million years ago found in Africa's Olduvai Gorge--that humans may have first settled Siberia as long as 2 million years ago. Using a relatively new technique called thermoluminescence on quartz grains at Diring Yuriakh, geoarchaeologist Michael Waters of Texas A&M University and colleagues at the University of Illinois, Chicago, now estimate that the tools are between 240,000 and 366,000 years old.
Some experts are resisting turning back the clock so far on taiga dwellers. Stanford anthropologist Richard Klein, for one, has reacted cautiously, contending that the presence of humans that far north so early is still "unlikely." Nonetheless, the stones raise the fascinating notion that premodern humans may have been more resourceful than scientists thought--a notion that gains support from a report yesterday (see ScienceNOW, 26 February) describing the discovery of 400,000-year-old wooden spears in Germany.
Who used the tools is anybody's guess. It could have been Homo erectus, known to have been in Africa and Asia at the time, or it could have been a transitional form known as archaic Homo sapiens, says archaeologist Robert Ackerman of Washington State University in Pullman. Whoever it was, says Bonnichsen, their presence "sets the stage" for people to have come over to North America from Asia far earlier than 12,500 years ago.