Scientific American Frontiers . Coming Into America. By Land or By Sea


		Skin-on-frame boats -- such as the one pictured here -- are thought to be similar to the boats used by early Americans.

In Vancouver, British Columbia, traditional boat expert Robert Morris uses techniques he learned from Canadian Inuit to build a "skin-on-frame" boat for FRONTIERS, similar to those Dennis Stanford thinks the Solutreans might have used to reach North America from Europe during the last Ice Age. Tough, light, flexible, and able to carry heavy loads, these boats are ideal for use along the edge of the ice

At the same time the Solutreans may have been traveling from Europe, people also could have reached America by boat from Asia. So both coasts could have been settled in time to account for all the early sites we know about.

In contrast, during the Ice Age the land route into America would have been limited by two ice sheets: the Laurentide, which covered most of North America east of the Rockies down to about Montana, and the Cordilleran, which ran from the Pacific coast across to the Laurentide.

It's possible that people could have walked into America before about 22,000 years ago, when there was still an ice-free land corridor just east of the Rockies between the two ice sheets. There's no evidence they did, but it would fit with Steve Holen's sites in Nebraska, where he believes humans were using mammoth bones at least 18,000 years ago.

The land corridor was blocked by the ice sheets until about 12,000 years ago. Clovis people were here a thousand years before then, so they or their predecessors must have walked into America much earlier, or come by boat to the Pacific or Atlantic coasts.

Robert Morris tests the seaworthy-ness of his boat.

Overall there are now many new ideas for how people got to America, and who they were. Instead of the first Americans being one people, coming one way, at one time, there may have been different people traveling a Pacific coastal route, an interior land route and an Atlantic ice route. Scientists are even considering several direct ocean routes.

Dennis Stanford, for one, is excited about what this suggests about the peopling of America and its implications for many people around the world. "If we're right, it shows how closely we're all related," he says, "And I like that."