Human Entrance into the New World via the Bering Land Bridge

Based on what we know from the archaeological record, the first people to cross over the Bering Land Bridge were Paleo-Indians (ancestors to the modern Native American tribes). They probably crossed the land bridge sometime before 13,000 years ago, pursuing large game animals. Because the land bridge was such a huge region in itself, it seems unlikely that these first human immigrants would have been aware that they were entering a new continent. The oldest well-dated human occupations in Alaska date from this time, but these archaeological sites are located in the interior regions of Alaska, so it seems probable that humans entered western Alaska at some earlier date. Shortly after their arrival, however, the Beringian ecosystem started to break down in the face of enormous environmental change. Temperatures rose rapidly about this time, bringing a wholesale change in regional vegetation. The mammoths, Pleistocene horses and camels, large-horned bison, and giant sloths that had roamed Beringia became extinct within a few centuries after the arrival of humans, along with many of the large predators. Some scientists argue that these cold-adapted animals could not tolerate the warm climates of the Holocene (the current interglacial period that began 10,000 years ago). This might be convincing, if it were not for the fact that the same cold-adapted species withstood the warm climates of several previous interglacial periods, at least one of which was probably substantially warmer than anything yet experienced in the Holocene. So climatic warming per se was not enough to cause the extinction of the large mammals. There must have been some unique environmental factors influencing the megafauna at the end of the last ice age. Some argue that human beings were the most important agent in dispatching the Pleistocene megafauna. Others argue that a combination of circumstances, including both environmental change and human hunting pressure, brought about the extinction of these animals. This question is still being debated by paleontologists.

The first Americans found a way to migrate south of Beringia and colonize the rest of North and South America. Their migration route remains an unsolved mystery (see Migration (Prehistory)), but two theories have gained prominence in recent years. One theory says that the Paleo-Indians migrated south along an ice-free corridor which opened up along the eastern flank of the Rocky Mountains in Alberta. After passing through this corridor, they spread out to colonize first North, then South America. A second theory states that people traveled by small boats or canoes, along the southern coast of Alaska and the west coast of British Columbia, thereby reaching icefree regions of the Pacific coast, and thence commencing their inland migration. The boat theory gains support from data at an archaeological site near the southern coast of Chile, called Monte Verde. At this site, human occupation has been documented back to more than 13,000 years ago. At that time, the ice-free corridor had not yet opened in Canada, so the inhabitants of Monte Verde almost certainly arrived there by boat.

Scott Elias

See also Archaeology of the Arctic: Alaska and Beringia; Holocene; Land Bridges and the Arctic Continental Shelf; Migration (Prehistory); Pleistocene Megafauna; Polar Steppe; Quaternary Period

Further Reading

Dixon, E.J., Bones, Boats, and Bison. Archaeology of the First Colonization of Western North America, Albuquerque, New Mexico: University of New Mexico Press, 1999 Elias, S.A., Ice Age History of Alaskan National Parks, Washington, District of Columbia: Smithsonian Institution Press, 1995

Elias, S.A. & J. Brigham-Grette (editors), "Beringian paleoen-vironments." Quaternary Science Reviews, 20(1-3) (2001): 574pp

Guthrie, R.D., Frozen Fauna of the Mammoth Steppe. The Story of Blue Babe, Chicago: University of Chicago Press, 1990

Hopkins, D.M., J.V. Matthews, C.E. Schweger, & S.B. Young,Paleoecology of Beringia, New York: Academic Press, 1982

Martin, P.S. & R.G. Klein (editors), Quaternary Extinctions, Tucson, Arizona: University of Arizona Press, 1989

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