Exactly how and when the peopling of the Americas took place has long been one of the hottest debates in science. For every new paper that emerges with evidence of an interior or coastal route, it seems another team publishes contradictory conclusions. Authors of a new review of archaeological, geological and paleogenetic research have concluded that both of the two main models are reasonable — and that a couple fringe theories are most definitely not.
If you’re a regular reader of Dead Things, you’re familiar with the ongoing kerfuffle between advocates of the two leading theories about how humans arrived in the Americas, but let’s do a quick recap.
Advocates of the interior route believe people from northeastern Siberia traveled on foot, likely following large herds of game animals, eastward over the land bridge of Beringia into what’s now Alaska. Beringia, by the way, has been exposed multiple times over the past several million years, during various ice ages when sea levels dropped. It’s sometime during the end of the last Ice Age that humans began their move from Siberia into Beringia and eventually Alaska. The interior route has been the dominant model for decades.
Then we’ve got the coastal route, often called the Kelp Highway model, which has gained traction particularly in the last couple years. It suggests people from northeastern Siberia followed the coast by boat, including along sea ice at times, around the northern Pacific and all the way to the Americas, continuing down the coast potentially as far as modern-day Chile. The resource-rich waters, full of fish, shellfish, seals and kelp, plus birds overhead, would have sustained the explorers.
Both models agree on some crucial points, particularly that individuals from northeastern Siberia traveled eastward, one way or another, to populate the Americas. The genetic connection between ancient Siberian and First American populations has been well-established within the last half-decade thanks to successful sequencing of ancient DNA from both sides of the Pacific.
