History and Culture
The Bering Land Bridge is as much a part of America's cultural heritage as Yellowstone or Yosemite, if not more so. The distance across the Bering Strait from Siberia to Alaska's Seward Peninsula is approximately 55 miles, and for several periods during the Pleistocene Ice Ages the trip could be made entirely on land instead of water. During additional periods, the passage from Siberia to North America could also have been made by small watercraft moving along coastlines.
Bering Land Bridge National Preserve commemorates this prehistoric peopling of the Americas from Asia some 13,000 or more years ago. It also preserves important future clues in this great detective story regarding human presence in the Americas.
Grasping the magnitude of Ice Age glaciation is possible today only on Earth's two extant polar ice sheets in Greenland and Antarctica. During the final Ice Age Push, vast ice sheets up to nearly two miles thick burdened much of America. Because the amount of water in Earth's hydrospere is constant, the great ice sheets' hoarding of global waters caused sea levels to fall significantly. As a result, land masses grew dramatically where continental shelves slope gradually, as they do in the Bering Strait.
Continental shelves are the shallow submarine plains that border many continents and typically end in steep slopes to an oceanic abyss. Where a wide continental shelf slopes gradually, a small drop in sea level can increase shoreline areas greatly.
During the time of the Bering Land Bridge, a sea level drop of approximately 300 feet during the Wisconsinan glacial period revealed a relatively flat, low-lying stretch of continental plain linking North America to Asia.
"Bridge" is really a misnomer, for the land mass ranged up to 1,000 miles wide. Just when humans first traversed Beringia is subject to less agreement. The Pleistocene epoch began 1.6 million years ago and ended only 10,000 years ago after a final onslaught of ice known as the late Wisconsinan glaciation. It is theoretically possible for people to have entered North America from Asia at repeated intervals between 40,000 and 13,000 years ago.
Sea level now rises an average of one foot per century because global warming is melting the great polar ice masses of the Arctic and Antarctic. The greenhouse effect and loss of stratospheric ozone may have increased the rate of global warming recently. Many clues to this intriguing puzzle about how and when humans first peopled the Americas undoubtedly lie underwater now.
Peopling the Americas
Whether on land, along Bering Sea coasts or across seasonal ice, humans crossed Beringia from Asia to enter North America about 13,000 or more years ago.
Humans were latecomers to this magnificent land mass so widely separated from other continents by vast oceans except near Earth's poles. Europe, the Middle East, Asia, the Indonesian Archipelago, and Australia already hosted humans. Well dated finds in both the southwestern United States and South America suggest that humans were in these locations about 12,000 years ago. Much closer to the Bering Land Bridge, the arctic coastline was not peopled year-round until about 4,500 years ago.
Artifacts suggest that people lived in both north and South America by some 12,000 years ago; by the time waters of the Bering Strait had become a significant barrier again. However, similarities between peoples of coastal Siberia and coastal Alaska show that the Bering Strait did not prevent contact between their cultures. Similar languages, shared spiritual practices, hunting tool and traditional dwelling similarities, distinctive fish cleaning methods, and meat preservation by fermentation are but a few examples ethnologists cite.
When Asia and Alaska were joined, marine mammals could not travel between the Bering and Chukchi seas. Neither could they range between the Atlantic and Pacific via arctic waters. Various seals, bowhead whales, walrus, and beluga whales were historically important to Inupiat Eskimos of the Seward Peninsula, and today they remain so for subsistence lifeways.
Walrus are a food mainstay for residents of the Diomedes and St. Lawrence Island. Polar bears may range the park and often ride ice floes through the Canadian Arctic to the Bering Strait. Marine mammals, still of immense importance along the Bering Strait, are not often sighted along the coast.
The Bering Land Bridge also served as a crossing point for animals other than humans during the Pleistocene. Making the journey with their hunters were muskox, lemmings, and some of the big Pleistocene animals, including mammoths.
When Europeans first came here the Eskimo population is estimated to have been 30,550. Today it numbers 36,000 in Alaska and Siberia.