Newspaper article The Christian Science Monitor

What Can Bison Fossils Teach Us about the First Americans?

Newspaper article The Christian Science Monitor

What Can Bison Fossils Teach Us about the First Americans?

Article excerpt

An ice-free corridor through the Rocky Mountains once thought to be humanity's path to the Americas from Alaska did not open in time to be the access route to the Americas, according to researchers who studied fossil samples of bison.

Using radiocarbon dating and DNA analysis, the researchers tracked the movements of bison into the corridor and determined it was fully open about 13,000 years ago, according to a press release from the University of California Santa Barbara, where some of the researchers are based.

The research suggests the Americas were likely colonized from Alaska through a coastal route on the Pacific instead. Peter Heintzman, one of the researchers, told the Guardian that after years of contention, the study shows the Pacific route as the most likely.

"It's really hard to think of any other ideas," Dr. Heintzman told the Guardian, pointing out that, 14,000 to 15,000 years ago, there was still quite a lot of ice. "And if that wasn't opened up you'd have to go around the ice, and going the coastal route is the simplest explanation."

Other experts agreed. Michael Waters, an archaeologist at Texas A&M University, College Station who was not involved in the study, told Science magazine the evidence, while indirect, is strong.

"This is the first strong empirical data indicating when that corridor was viable," he said.

The earliest evidence of humans south of the ice sheets places them there at least 15,000 years ago, and it is believed that the Cordilleran and Laurentide ice sheets merged some 21,000 years ago at the peak of the last ice age. The closure of the passage known as the Rocky Mountain corridor created two distinct bison populations north and south of the ice sheets.

"The interesting thing about the [Rocky Mountain] corridor is that it was open until about 21,000 to 23,000 years ago, when the ice sheets to the west and east came together and completely separated populations," Heintzman told the Guardian.

By studying the 78 bison samples, researchers could determine when the northern bison moved southward and vice versa. …

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