Definition & Location of Beringia The boundaries of Beringia have expanded since Eric Hultén's time. Beringia is now considered to be a continuous land mass that once spanned from the banks of the Mackenzie River in Canada to the banks of the Lena River in Siberia (West, 1998). Beringia includes eastern Siberia, most of modern Alaska, parts of the Yukon and Northwest Territories, and the shallow continental shelves.
The Bering Land Bridge The Bering Land Bridge made it's first appearance at least 70 mya (million years ago). It was exposed for most of the past 2 or more million years until it was completely flooded with water 11,000 ya (years ago). The land bridge was huge! It may have been twice the size of Texas-579,000 square miles- (Elias, 1997) and 1,000 miles wide in it's prime. We can actually see parts of the land bridge today. St. Lawrence, and St. Paul islands formed part of the central highlands of the Bering Land Bridge. The flat floors of both the Chukchi and Bering Seas, and the shallow continental shelves were the low-lying continental plains.
Why all the interest in Beringia? Beringia is very important because it was an unglaciated part of the Arctic. The rest of the Arctic was buried under continental ice sheets that were 3 km (almost 2 miles) thick. The idea of a lost land mass in not unique it history. Think of the lost civilization of Atlantis. Because sea-levels decreased dramatically for such a long time, an entire land mass was exposed and underwent it's own distinct evolution influenced by the flora and fauna Siberia and Alaska. Circulation between two major oceans were cut off in the Bering Straight.
Beringia provided a refugium for plants, animals, insects, and humans. Isolation, dispersal, and assimilation of species led to the adaptation and evolution of new species over time. The Bering Land Bridge was a bridge for both the Siberian and Alaskan flora, fauna, and humans. Human migration and ancestry is of particular interest in the discussions about the land bridge. Did the first people walk over the land bridge and then colonize the rest of North America? Where did they come from? When did they arrive? These are questions that have not yet been answered. So what was Beringia like during the last glaciation?