Thursday, August 11, 2016

The first North Americans didn't cross the Bering Land Bridge

According to the traditional story, the first people to settle North America arrived around 13,000 years ago near present-day Clovis, New Mexico, having crossed the Bering Land Bridge from Asia and traversed a recently opened, 1,000-mile-long corridor between the Laurentide and Cordilleran ice sheets that covered much of the continent.

Well, that story is almost certainly wrong. For one thing, DNA and archaeological evidence from a number of sites in the United States and Canada demonstrate that humans not only inhabited North America at least 15,000 years ago, but were by that point pretty much spread throughout the continent.

But it’s a different aspect of the story that University of Copenhagen researchers Mikkel Pederson and Eske Willerslev take issue with. “Whether the ice-free corridor could have been used for a Clovis-age migration depends on when it became biologically viable,” Pederson, Willerslev, and their colleagues write in Nature. In other words, it depends on whether there was enough to eat along the way from Alaska to the heart of North America.

To see how much food might have been available, the team took core samples from lake beds in the Peace River basin, right in the middle of the path the ice corridor once took. The researchers searched those for fossils, pollen, and other biological materials. ... The team’s analysis suggests that the region was largely lacking in plant life prior to about 12,600 years ago...

Although the results do not preclude the possibility that people did at some point travel through the corridor, it’s most likely the first people to arrive in the present-day U.S. came via the Pacific Coast, the authors argue.
--Nathan Collins, Pacific Standard, on another scientific folk story on the ropes