One If By Land, Two If By Sea

Did First Americans Arrive By Land And Sea? A growing number of experts are radically rethinking how the Americas were first populated. Scientists say an emerging picture suggests that the earliest people to reach the New World may have arrived by both land and coastal routes. For the last several decades, prevailing theory held that a small group of big game hunters in Siberia followed the Pleistocene megafauna—mammoth, mastodon, and extinct bison—across a land bridge that formed during the last Ice Age. Known as Beringia, it connected Asia to Alaska and northwestern Canada. As the glaciers began to retreat, an ice-free corridor opened up around 12,000 years ago, allowing people to make their way south to populate North and South America. ... For decades it was simply assumed that the coast of Beringia was an inhospitable place to live, said Erlandson. New evidence suggests that instead of a straight-line coast, the southern coastline of Beringia was comprised of hundreds of islands, shallow bays, and inlets. Such coastal topography would have facilitated coastal living and migration.

One issue this article doesn't follow up on is the question of megafauna. The prevailing image of the first Americans is of big-game hunters following the mastodons from Siberia. But a coastal route would suggest a much greater emphasis on smaller animals and plants. The Clovis culture would then be an indigenous adaptation, developed as people left their maritime environments and moved inland to where the big game was.

I wonder what the shift from thinking about the first Americans as generalists rather than big game specialists says about how rapidly the continent was populated. Many people believe that the megafauna were wiped out in part by a rapid population expansion of hunters -- the "blitzkreig" hypothesis. I have a preconceived skepticism about this theory based on closer investigations of the cases of South America and Australia. This is bolstered by the historical evidence from hunting of the most mega of the fauna left after the ice ages, the bison. We hear a lot about how conservation-minded the Indians of the plains were in contrast to the wasteful whites who nearly wiped the bison out. But as Shepard Krech points out, another important factor was that the plains Indians simply weren't capable of putting that much hunting pressure on the bison. To do so would have required many more mouths to feed than the plains Indians had (clearly the Lakota never read Malthus). This makes me wonder why the Paleoindians would have been different (though they certainly could have been -- one could argue that other factors, such as climate, reduced the megafauna's numbers so that they were extinct-able whereas the bison remained too numerous).

On the one hand, it seems like generalists would be able to expand more rapidly, because they're less dependent on any particular resource. It seems like they could more quickly pick up new food sources as they moved across the continent, rather than being limited by the range of the megafauna. Then again, the "blitzkreig" hypothesis only requires rapid population expansion through the areas with megafauna. On the other hand, the archaeological evidence points in the other direction -- there are many Clovis sites, whereas there are no universally agreed-upon pre-Clovis sites (though I personally am pretty confident in Meadowcroft). So either the pre-Clovis generalists tread very lightly upon the land, or there was no population explosion until Clovis times.