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Beringian Civilization

Beringian Civilization The Bering Strait, separating Siberia from Alaska in the North Pacific.
Photo Credit: NASA [Public domain], via Wikimedia Commons

Humans may have inhabited the Bering Land Bridge for 10,000 years.


Transcript

The lost civilization of Beringia. I'm Bob Hirshon and this is Science Update. 

About twenty thousand years ago, humans reached the Americas from Asia by crossing Beringia, a land bridge that once connected present-day Russia and Alaska. But according to University of Utah anthropological geneticist Dennis O’Rourke, Beringia may have been more than just a thruway.

In the latest issue of the journal Science, O’Rourke and his colleagues piece together recent evidence that suggests that Beringia’s mostly rugged environment was more diverse than previously thought, with areas of shrubs, trees, and surprisingly mild climates. O’Rourke’s team suspects people settled there for long periods.

O’Rourke:
They didn’t cover vast amounts of the territory, but they were sort of little isolated, ecological zones and very congenial to human habitation.

He says that genetic evidence suggests people stayed in Beringia for up to ten thousand years before moving south. I’m Bob Hirshon for AAAS, the Science Society.


Making Sense of the Research

During the 2008 Presidential campaign, Republican Vice-Presidential candidate and former Alaska governor Sarah Palin famously said, “I can see Russia from my house.” She was referring to the northeastern border of Russia, which lies across a narrow body of water called the Bering Strait from the western coast of Alaska. 

At its narrowest point, the Bering Strait today is just over 50 miles wide. However, during a period called the “last glacial maximum” (the peak of what's commonly called the last Ice Age), the land masses of present-day Russia and the United States were connected. That's because sea levels then were about 400 feet lower than today, since large volumes of seawater had frozen into glaciers that were slowly moving across the North American landmass. As a result, parts of the present-day seafloor were dry land at the time.

The region that connected the two continents, called Beringia, last emerged over 20,000 years ago and disappeared when sea levels reached their current levels about 6,000 years ago. At its peak, it was up to 1,000 miles wide (greater than the distance from Portland, Oregon, to Los Angeles, California). During that time, genetic, anthropoligical, and archaeological evidence tells us that humans crossed this land mass to enter the Americas from Asia. 

The question, though, was how long they stayed. Genetic evidence indicates that the Native American genome became isolated from the Asian genome about 25,000 years ago, but didn't spread thorughout the Americas until 15,000 years ago. However, archaeologists have found no evidence of human civilization in the areas of Beringia that remain above water, and the area was widely believed to be too barren and cold for humans to settle in.

But O'Rourke's article, which doesn't present new research but synthesizes information from several different recent studies, suggests that we've been simplifying the picture of Beringia. He notes that recently, evidence from deep seafloor sediments around Beringia found pollens of trees and shrubs. That suggests that the lowlands of Beringia may have been more hospitable to plants, grazing animals, and therefore humans. Other evidence suggests that although these regions would have been cold in the winter, they may have been much milder in the summer than previously thought.

All this makes it more plausible that humans settled in Berigina's patchy lowlands for up to 10,000 years, as the genetic evidence suggests. And since these lowland areas are now underwater, that would explain why these civilizations left no archaeological trace.

Now try and answer these questions:

  1. What is Beringia? Where is it?
  2. What do we know about its role in the migration of humans from Asia to America?
  3. Thinking about how long humans stayed in Beringia, how has the genetic evidence seemingly contradicted the archaeological evidence?
  4. What evidence does O'Rourke present that may resolve this contradiction?
You may want to check out these related resources:
 

In the Science Update Pueblo Migrations, you'll hear about a 20-year effort to learn what happened to the ancient residents of the American Southwest.

The online tool Migration Station, from National Geographic, uses a virtual train station to promote understanding of why people migrate.


Going Further


For Educators

In the series of lessons called Collapse, students learn about factors that cause major social changes and about prerequisites for a society’s survival. 

In the Science Update lesson Pueblo Migrations, you'll hear about a 20-year effort to learn what happened to the ancient residents of the American Southwest.

The online tool Migration Station, from National Geographic, uses a virtual train station to promote understanding of why people migrate.


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