The New World’s ‘10,000-year missing link’


The outlines of  Siberia (left) and Alaska (right) — in dashed lines — go head to head. The area in darker green (now submerged by seawater) represents Beringia near the end of the last glacial maximum, when sea levels were low and ice sheets prevented migrants from Siberia from reaching America. | Photo courtesy of Wlliam Manley, Institute of Arctic and Alpine Research, University of Colorado.

Did you ever wonder how ancient peoples managed to stay warm in bitterly cold weather like this?

Ice-age mammal bones provided a nice fire, researchers say. But to get the fire started, Siberian migrants who began a trek to America 25,000 years ago needed woody shrubs, which were growing in only one region, according to a study in Science. The findings help explain how the migrants survived for 10,000 years in what was thought to be a land devoid of trees and why no archaeological traces of their settlements have been found.

If you think back to 7th-grade geography, you may have wondered how all those people from Asia could have crossed what looks like a puny Bering Land Bridge. Well, about 20,000 years ago, “Beringia” was a vast plain more than 600 miles wide, and its shrub tundra was “the only region of the Arctic where any woody plants were growing,” says Scott Elias, a study co-author and geography professor at Royal Holloway, University of London.

“For a long time, many of us thought the land bridge was a uniform tundra-steppe environment,” grassland without shrubs and trees, says University of Utah anthropologist Dennis O’Rourke, who took part in the research.

But their study of fossilized insects, plants and pollen from land that is now under the Bering Sea shows that Beringia had a relatively mild summer and that its terrain could have provided wood for cozy fires during what’s known as the last glacial maximum. The migrants were able to camp out there from about 25,000 years ago until glacial ice sheets melted and opened paths to America about 15,000 years ago, O’Rourke says.

“This work fills in a 10,000-year missing link in the story of the peopling of the New World,” Elias says.

Mutations in Native American DNA have indicated that the Siberian migrants were isolated for thousands of years. The geneticists’ theory, proposed in 1997, has been considered far-fetched and not followed up by other disciplines, until now, according to University of Colorado researcher John Hoffecker, the lead author of the latest study.