Ice Age Migrations Populated America and Siberia From Beringian Refugees

ice age migrations

Ice age migrations that populated North America from Siberia may have been a two-way street. Researchers now theorize that people from Beringia, a subcontinent that once linked Siberia and Alaska, actually populated both Siberia and North America. Linguistic evidence is now mounting up to reinforce geological and genetic evidence that separate bands of refugees, fleeing the encroaching glaciations across Siberia and Northern China, may have met on the Beringia isthmus, mingled and waited, trapped for 15,000 years by glaciers on either end of the isthmus, isolated  from the world.

Ice age migrations, long a staple for imaginative fiction, are now being endorsed by serious scientists, who have been studying the impact of glaciation periods upon early human communities in different parts of the world. Some of that scientific inquiry is beginning to unravel the mysteries of how people first settled in North America. The Beringia theory is a prime example of this thinking.

According to this theory, hemmed in by ice walls on both sides of the land bridge where the Bering Straits are now, successive bands of Siberian refugees from different tribal backgrounds gradually developed a new common language that was probably an amalgamation of several different dialects that the successive waves of immigrants brought with them. When the ice started to recede, between 10,000 and 15,000 years ago, some of the Beringian refugees went home to Siberia, while others forged ahead into North America.

ice age migrations
At top: artist’s rendering of what Beringia might have looked like. Above: Bering Sea today as seen from a satellite in orbit

Beringia was once thought to have been a narrow isthmus between the two continents, but recent deep-sea oil and gas explorations have brought up evidence that Beringia was broad plain, perhaps 600 miles wide, that was once capable of supporting a substantial human population, according to Dr John F. Hoffecker, a University of Colorado archaeologist. Hoffecker believes that the Beringia was a refugium, a place of refuge for Siberians fleeing the Last Glacial Maximum, during a cold “snap” that lasted from 30,000 B.C.E to 15,000 B.C.E., a timeline that exceeds all recorded human history. There may have been a series of ice age migrations into Beringia, rather than a single event, as the ice pushed one community after another to make the bitter choice between emigration and freezing or starving to death.

In the 1980s, geneticists Michael Hammer and Tatiana Karafet led a team of American and Russian scientists at the Laboratory of Molecular Systematics and Evolution  at the University of Arizona that compared the DNA of aboriginal Siberian tribal people with North American Native people. The DNA evidence indicated that there was a relationship between the Siberian natives and the North American natives. The genetic evidence also indicated there was also a substantial “back migration” from Beringian refugees that brought DNA samples from the Beringian population group back to Siberia. So, the evidence appeared to indicate that the Siberian people first occupied Beringia and, then, the people from Beringia eventually repopulated Siberia, and introduced human activity to North America.

In 2008 by Dr. Edward Vajda, a linguist at Western Washington University, reported that he had identified a relationship between a group of language dialects spoken along the Yenisei river valley in central Siberia and the Na-Dene language group, spoken by native tribes in Alaska and Western Canada, and by the Navajo and Apache people in the Southwestern United States.

New linguistic evidence, just reported in PLOS One (Public Library of Science), an open access, peer-reviewed journal, now suggests that, indeed, there is more support for the theory that some Beringians headed back to Siberia while others forged ahead into North America when the ice finally receded.

Dr. Vajda’s research was focused on verb modifiers. Mark A. Sicoli of Georgetown University and Gary Holton of the University of Alaska have now compared the grammatical features of the two language groups, which are considered more reliable than vocabulary. Their findings contradict previous assumptions that the Na-Dene language of the North American peoples is a descendant of the Yeniseian language spoken in Siberia.

On the contrary, both the Yeniseian language and the Na-Dene language appear to have descended from a common, and now lost, mother tongue. This theory suggests that the Beringian refugees who returned home to Siberia may have encountered remnants of the Siberian tribes that survived the cold snap, intermarried with them and blended their Beringian language with the dialects then spoken in that area.

It was originally thought that the Beringians who forged ahead into North America found no one waiting for them when they arrived, and continued to live in virtual isolation for thousands of years before coming into contact with other language groups. However, it now appears that there may have been earlier migrations from Beringia to North America that occurred early on, before the ice walls came down. With multiple population transfers taking place over thousands of years, linguistic changes would naturally develop between different migrations, which may account for the changes that have taken place in the Na-Dene dialect.

Communities do not move back where they came from, when where they came from was as inhospitable as Siberia was at the end of the last glacial maximum. Something must have happened to force them to leave. When ice melts, oceans rise. The Beringians just might  have been flooded out of their adopted homeland as the oceans rose around Beringia.

If the Yeniseian language was brought back to the Yenisei river valley and it was no longer similar to what was spoken there before, the question arises as to the actual identity of the people who originally settled the Beringian isthmus. The ice age migrations between Siberia and North America may have a common ancestry of unknown origin, but that is only to be expected when investigating events that occurred 30,000 years ago, leaving not a single shred of physical evidence behind.

By Alan M. Milner


Smithsonian National Museum of Natural History/Arctic Studies Center
New York Times
PLoS One