It is unclear when or how people first came to the Americas. Native American oral histories on the subject vary, and different groups have different histories. Some describe journeys by land through different worlds and environments, while others describe coming by water, and others believe that the first people originated of the American continents. The first Europeans to come to the Americas in historic times believed that Native Americans originated in the Old World (Europe, Africa, and Asia), based on their biblical beliefs that the genesis of all people occurred in the Garden of Eden. In addition to oral and biblical histories, archaeological research provides science-based evidence addressing the question of human origins in the Americas by dating geological events and artifacts in the context of environmental change. Most archaeological sites are dated by the radiocarbon method, and radiocarbon years can be different than calendar (solar) years. The dates used in this presentation are calibrated to calendar years.
Migration Routes and Colonization
Scientific evidence indicates that humans originated and evolved in the Old World, first in Africa, then colonizing Asia, Europe and, later, Australia. There are many early (200,000- to 20,000-year-old) sites throughout the Americas that some researchers suggest were occupied prior to the last Ice Age, but the dating or integrity of all these sites has been questioned by subsequent research. The fossil remains of early humans, such as Homo erectus and Neanderthals, found in Africa, Europe, and Asia are hundreds of thousands years old. However, the fossil remains of humans found in North and South America are not that old. In fact, the earliest reliably dated human remains from the Americas are only about 13,350 years old. This and other evidence suggests people first arrived in the Americas no more than about 18,000 years ago, near the end of the last Ice Age. The limited extent of ice-free migration routes during that time limited possible migration routes available to the first people to colonize the Americas.
The idea that humans may have first entered the Americas via a land route in the high northern latitudes was first suggested by a Spanish priest, Fray de Acosta, more than 400 years ago. Over time, this concept became deeply embedded in scientific thought. Archaeological evidence indicated that people living in central Asia hunted large Ice Age animals, like the extinct wooly mammoth, as well as other animals that did not become extinct during the last Ice Age, such as bison. According to this theory, early people, hunting large Ice Age animals, crossed the land bridge into Alaska and then moved south into central-western Canada. From there they were able to colonize the more southern areas of North America and eventually South America. This theory seemed plausible because some of the oldest archaeological sites in the Americas contained the bones of Ice Age animals similar to those people had hunted in Asia. Research conducted in the 1980s and 1990s questioned the viability of this theory and led to a reconsideration of other routes.
The climate was much colder during the last Ice Age, and massive glaciers formed a huge ice sheet covering most of Canada. The ice blocked access between what is today Alaska and the continental United States. Polar sea ice extended south into the Atlantic, covering Greenland, Iceland, and all but the most southern areas of Ireland and England. Because much of the earth's water was trapped in glacial ice, the sea level was lower than it is today. The continental shelves and the floor of the Bering and Chukchi Seas were exposed as dry land, creating the Bering Land Bridge. The geography of the Ice Age limited migration routes into the Americas to four possibilities: (1) the Beringian Mid-Continental, (2) the Northwest Coastal, (3) the Pacific, and (4) the Atlantic. By analyzing the environmental conditions that existed during the last Ice Age, it is possible to evaluate each of these possible routes.
The Beringian Mid-Continental route presumes that hunters and gatherers first entered North America from Asia across the Bering Land Bridge. They then moved south into central-western Canada through a hypothetical ice-free corridor. Geologists working in Canada have demonstrated that such a corridor did not exist during most of the Ice Age and that connections between eastern Beringia and areas south of the continental glaciers were not established until about 13,000 years ago. Supporting this conclusion, no animal bones dating between 25,000 to 13,000 years ago have been found in the region formerly believed to have been ice-free. This evidence indicates that the ice-free corridor did not exist during the last Ice Age. It precludes a midcontinental route for human entry between about 21,000 and 13,000 years ago, possibly even later.
However, glacial melting (a process known as deglaciation) along the Northwest Coast of North America had begun by 16,800 years ago and was sufficiently advanced to enable people using watercraft to colonize coastal areas by 15,350 years ago. The remains of land and sea mammals, birds, and fish dating to this time have been discovered along the Northwest Coast, demonstrating sufficient resources for people to survive. Because earlier geologic misinterpretations indicated that the region had been ice covered until about 11,350 years ago, very little archaeological work has been undertaken to explore this region as a possible migration route.
Whereas the Bering Land Bridge–ice-free corridor model for human colonization requires an economy based on hunting terrestrial mammals, freshwater fishing, and pedestrian travel, the coastal hypothesis suggests an economy based on marine mammal hunting, saltwater fishing/shellfish gathering, and the use of watercraft. Each would have required different types of adaptations to the New World. If the coastal colonization hypothesis is to be fully evaluated, the late Pleistocene coastal archaeology of western North America will require additional and sustained research efforts equivalent to those that have traditionally focused on midcontinental North America.
Some researchers believe humans may have crossed the vast expanse of the Pacific, colonizing South America and later moving into North America. Support for this theory is based on sites such as Monte Verde in southern Chile and Tiama-Tiama in northern Venezuela, which may be older than any site in North America. Biological evidence suggests that some of the earliest skeletons found in South America share similarities with examples from Polynesia and Australia.
A North Atlantic migration has been proposed by some who recognize similarities in tool-making technology between the Clovis complex of North America, dating to between 13,300 and 12,850 years ago, and the Solutrean tradition of Europe. This has led some archaeologists to suggest that, with the use of watercraft, Solutrean people (maritime hunters and fishing people) may have been able to reach North America from Europe by moving westward along the sea ice edge of the North Atlantic during the last Ice Age. Although the Solutrean tradition ended about 19,000 years ago in Portugal and Spain, the theory suggests that several pre-Clovis sites in North America, possibly including Meadowcroft Rock Shelter and the Cactus Hill site, may indicate continuity between the two cultural traditions.
While all these migration theories are possible, the preponderance of linguistic and biological evidence indicates that Native Americans most likely originated somewhere in northeastern Asia. The Northwest Coast, midcontinental, and Pacific routes lead from there to the Americas. Because the mid-continental route was not open until 11,000 to 11,500 years ago and transoceanic travel is so dangerous, the most plausible route for the first colonization of the Americas seems to be along the southern coast of the Bering Land Bridge and then southward along the Northwest Coast of North America.
These potential migration routes were not mutually exclusive. The colonization of the Americas may have involved many groups of people, possibly originating from different places in the Old World at different times. Migration was probably a complex process that spanned a long period of time. There are tantalizing biological and technological clues that suggest that, prior to the arrival of Europeans in the fifteenth century, there was possible contact, and possibly even colonization, between the Americas and Australia, Polynesia, Europe, and even Africa.
Many sites in the Americas that appear to be reliably dated and interpreted are older than 13,000 years. Some of the better-known sites in North America include Meadowcroft Rock Shelter in Pennsylvania (19,000 years old), Cactus Hill in Virginia (18,000 years old), the Schaefer and Hebior sites in Wisconsin (14,200 years old), Swan Point in Alaska (13,900), Little Salt Springs in Florida (13,800 years old), and Manis Mastodon site in Washington State (13,700 years old). Archaeological sites dating to this time period are rare and appear to have been occupied by few people for short periods of time. The little data available suggest that the population was small and that people made their living by hunting, gathering, and foraging. It is possible that many sites dating to this time period are currently underwater because they were located along the coast and were flooded by the rising sea level at the end of the Ice Age.
Regional Development (13,500–10,000 years ago)
Archaeologists generally separate the archaeology of North America into time periods that are subdivided into traditions and complexes. The term "Paleo-Indian tradition" was introduced during the 1940s and is widely used to characterize sites older than about 9,000 years. These sites contain stone projectile points that generally have a characteristic "flute" extending from the base toward the tip, along with a wide variety of other artifacts and later "lanceolate" types of projectile points. The people who made and used these tools subsisted by hunting, fishing, and foraging; they often hunted large animals such as bison. The Paleo-Indian tradition is recognized throughout most of North America. This is the earliest evidence, based on artifacts found at diverse archaeological sites throughout North and South America, documenting the widespread settlement of the New World.
In the area east of the Mississippi River, there appears to have been a gradual transition from Paleo-Indian tradition to artifact assemblages characteristic of later archaeological cultures. In the central part of the North American continent (the Great Plains region), the Paleo-Indian tradition includes the Clovis complex dating from 13,300 to 12,900 years ago and the Folsom complex, which lasted from 12,900 until 11,800 years ago. Clovis sites are the only ones associated with mammoth hunting in North America. (Folsom sites are most commonly associated with bison hunting.) Mammoths (Ice Age animals related to elephants) became extinct at this time. This and other evidence has led some scientists to suggest that the first people to colonize the Americas may have caused the extinction of these and other large mammals as a result of overhunting or possibly the introduction of new diseases. However, other theories suggest that their extinction was due to environmental change.
Fluted points have been found in the far west of North America, the region extending from the continental divide of the Rocky Mountains west to the Pacific Ocean. In the Far West these types of artifacts are believed to be about the same age as the Clovis and Folsom complexes because they are stylistically similar to the examples from the Great Plains. They are commonly referred to as the Western Fluted Point tradition. However, another group of artifacts found throughout the Far West includes stone projectile points with "stemmed" bases rather than flutes. Although they have not been firmly dated, some archaeologists believe they are as old as Clovis artifacts, possibly even older. The remains of plants, animals, birds, and fish indicate that the economy of the people of the Western Stemmed and Fluted Point traditions and those living on the Great Plains practiced a generalized economy, occasionally hunting large mammals such as mammoth and bison, but more typically harvesting a wide array of resources, including birds, fish, and plant foods whenever and wherever they were available.
In the Far North, in an area known as eastern Beringia (Alaska and areas of extreme northwestern Canada that were not covered by glacial ice during the last Ice Age, the oldest archaeological remains are very different. They are called the Denali complex. The earliest radiocarbon dates for the Denali complex are about 13,900 calendar years ago, and the complex appears to have persisted until at least 8,000 years ago. The artifacts are very similar to those characteristic of the Upper Paleolithic (the latter period of the Old Stone Age) in Europe and Asia, and they clearly have their origins there. Along with a variety of other types of tools, these people used tiny slivers of stone, called microblades, inset in slots carved in antler or bone projectile points. These types of artifacts are very different from those of the Paleo-Indian and Western Stemmed and Fluted Point traditions, suggesting that these artifacts were made by different groups of people with different cultural backgrounds.
When the continental glaciers started to melt about 17,000 years ago, the sea level rose rapidly. Land that previously had been covered by glaciers was exposed for the first time since the beginning of the last Ice Age and was rapidly colonized by plants and animals. People living along the coasts of North America retreated inland in response to rising sea levels. In other areas, people also began to occupy new environments created by deglaciation.
Scientific evidence suggests that North and South America were the last continents on Earth to be occupied by people. Colonization took place during a time of dramatic climate change when the sea level was rising rapidly, many Ice Age animals were becoming extinct, the land was rebounding (rising upward) as the great weight of the glaciers disappeared, and terrestrial ecosystems were undergoing massive reorganization. Understanding the timing, origins, culture, and technology of the first people to occupy the Americas is important because these adaptations established the foundation for the subsequent cultural development in the Americas and for the rich and diverse cultures that followed.
E. James Dixon
Adovasio, J. M., J. D. Gunn, J. Donahue, and R. Stuckenrath. 1978. "Meadowcroft Rockshelter, 1977: An Overview." American Antiquity 43: 632-651.; Akazawa, T., and E.J.E. Szathmary, eds. 1996. Prehistoric Mongoloid Dispersals. New York: Oxford University Press.; Bradley, B., and D. Stanford. 2004. "The North Atlantic Ice-Edge Corridor: A Possible Palaeolithic Route to the New World." World Archaeology 36, no. 1: 469–478.; Burns, J. A. 1996. "Vertebrate Paleontology and the Alleged Ice-Free Corridor: The Meat of the Matter." Quaternary International 32: 107–112.; Dillehay, T. D. 2000. The Settlement of the Americas: A New Prehistory. New York: Basic Books.; Dixon, E. James. 1999. Boats, Bones, and Bison: Archaeology and the First Colonization of Western North America. Albuquerque: University of New Mexico Press.; Fagan, B. M. 1987. The Great Journey: The Peopling of Ancient America. London: Thames and Hudson.; Fladmark, K. R. 1979 "Routes: Alternative Migration Corridors for Early Man in North America." American Antiquity 44: 55–69.; Frison, G. C. 1991. Prehistoric Hunters of the High Plains. New York: Academic Press.; Gustafson, C. E., D. Gilbow, and R. D. Daugherty. 1979. "The Manis Mastodon Site: Early Man on the Olympic Peninsula." Canadian Journal of Archaeology 3: 157–164.; Jablonski, N. G., ed. 2001. The First Americans. San Francisco: California Academy of Sciences Scientific Publications.; Koppel, T. 2003. Lost World: Rewriting Prehistory—How New Science Is Tracing America's Ice Age Mariners. New York: Atria Books.; Madsen, D. B., ed. 2004. Entering America: Northeast Asia and Beringia Before the Last Glacial Maximum. Salt Lake City: University of Utah Press.; Parfit, M. 2000. "Hunt for the First Americans." National Geographic. (December), 40–67.; West, F. H., ed. 1996. American Beginnings. Chicago: University of Chicago Press.