Traditional theories suggest that big-animal hunters crossed the Bering Strait from North Asia into the Americas over a land-and-ice bridge (Beringia). This bridge existed from 45,000 to 12,000 BCE (47,000–14,000 BP). Small isolated groups of hunter-gatherers migrated alongside herds of large herbivores far into Alaska. From c. 16,500 – c. 13,500 BCE (c. 18,500 – c. 15,500 BP), ice-free corridors developed along the Pacific coast and valleys of North America. This allowed animals, followed by humans, to migrate south into the interior of the continent. The people went on foot or used primitive boats along the coastline. The precise dates and routes of the peopling of the New World remain subjects of ongoing debate.
Sites in Alaska (East Beringia) are where some of the earliest evidence has been found of Paleo-Indians, followed by archaeological sites in northern British Columbia, western Alberta and the Old Crow Flats region in the Yukon. The Paleo-Indian would eventually flourish all over the Americas. These peoples were spread over a wide geographical area; thus there were regional variations in lifestyles. However, all the individual groups shared a common style of stone tool production, making knapping styles and progress identifiable. This early Paleo-Indian period's lithic reduction tool adaptations have been found across the Americas, utilized by highly mobile bands consisting of approximately 20 to 60 members of an extended family. Food would have been plentiful during the few warm months of the year. Lakes and rivers were teeming with many species of fish, birds and aquatic mammals. Nuts, berries and edible roots could be found in the forests and marshes. The fall would have been a busy time because foodstuffs would have to be stored and clothing made ready for the winter. During the winter, coastal fishing groups moved inland to hunt and trap fresh food and furs.
Late ice age climatic changes caused plant communities and animal populations to change. Groups moved from place to place as preferred resources were depleted and new supplies were sought. Small bands utilized hunting and gathering during the spring and summer months, then broke into smaller direct family groups for the fall and winter. Family groups moved every 3–6 days, possibly traveling up to 360 km (220 mi) a year. Diets were often sustaining and rich in protein due to successful hunting. Clothing was made from a variety of animal hides that were also used for shelter construction. During much of the Early and Middle Paleo-Indian periods, inland bands are thought to have subsisted primarily through hunting now-extinct megafauna. Large Pleistocene mammals were the giant beaver, steppe wisent, musk ox, mastodons, woolly mammoths and ancient reindeer (early caribou).
The glaciers that covered the northern half of the continent began to gradually melt, exposing new land for occupation around 17,500–14,500 years ago. At the same time as this was occurring, worldwide extinctions among the large mammals began. In North America, camelids and equids eventually died off, the latter not to reappear on the continent until the Spanish reintroduced the horse near the end of the 15th century CE. As the Quaternary extinction event was happening, the Late Paleo-Indians would have relied more on other means of subsistence.
From c. 10,500 – c. 9,500 BCE (c. 12,500 – c. 11,500 BP), the broad-spectrum big game hunters of the great plains began to focus on a single animal species: the bison (an early cousin of the American bison). The earliest known of these bison-oriented hunting traditions is the Folsom tradition. Folsom peoples traveled in small family groups for most of the year, returning yearly to the same springs and other favored locations on higher ground. There they would camp for a few days, perhaps erecting a temporary shelter, making and/or repairing some stone tools, or processing some meat, then moving on. Paleo-Indians were not numerous and population densities were quite low.
Different types of Projectile points, from the Paleo-Indian periods in southeastern North America.
Paleo-Indians are generally classified by lithic reduction or lithic core "styles" and by regional adaptations.Lithic technology fluted spear points, like other spear points, are collectively called projectile points. The projectiles are constructed from chipped stones that have a long groove called a "flute". The spear points would typically be made by chipping a single flake from each side of the point. The point was then tied onto a spear of wood or bone. As the environment changed due to the ice age ending around 17–13KaBP on short, and around 25–27Ka BP on the long, many animals migrated overland to take advantage of the new sources of food. Humans following these animals, such as bison, mammoth and mastodon, thus gained the name big-game hunters. Pacific coastal groups of the period would have relied on fishing as the prime source of sustenance.
Archaeologists are piecing together evidence that the earliest human settlements in North America were thousands of years before the appearance of the current Paleo-Indian time frame (before the late glacial maximum 20,000 plus years ago). Evidence indicates that people were living as far east as northern Yukon, in the glacier-free zone called Beringia before 30,000 BCE (32,000 BP). Until recently, it was generally believed that the first Paleo-Indian people to arrive in North America belonged to the Clovis culture. This archaeological phase was named after the city of Clovis, New Mexico, where in 1936 unique Clovis points were found in situ at the site of Blackwater Draw, where they were directly associated with the bones of Pleistocene animals.
In South America, the site of Monte Verde indicates that its population was probably territorial and resided in their river basin for most of the year. Some other South American groups, on the other hand, were highly mobile and hunted big-game animals such as mastodon and giant sloths. They used classic bifacial projectile point technology.
The primary examples are populations associated with El Jobo points (Venezuela), fish-tail or Magallanes points (various parts of the continent, but mainly the southern half), and Paijan points (Peru and Ecuador) at sites in grasslands, savanna plains, and patchy forests.
The dating for these sites ranges from c. 14,000 BP (for Taima-Taima in Venezuela) to c. 10,000 BP. The bi-pointed El Jobo projectile points were mostly distributed in north-western Venezuela; from the Gulf of Venezuela to the high mountains and valleys. The population using them were hunter-gatherers that seemed to remain within a certain circumscribed territory. El Jobo points were probably the earliest, going back to c. 14,200 – c. 12,980 BP and they were used for hunting large mammals. In contrast, the fish-tail points, dating to c. 11,000 B.P. in Patagonia, had a much wider geographical distribution, but mostly in the central and southern part of the continent.
The Archaic period in the Americas saw a changing environment featuring a warmer more arid climate and the disappearance of the last megafauna. The majority of population groups at this time were still highly mobile hunter-gatherers, but now individual groups started to focus on resources available to them locally. Thus with the passage of time there is a pattern of increasing regional generalization like the Southwest, Arctic, Poverty, Dalton and Plano traditions. These regional adaptations would become the norm, with reliance less on hunting and gathering, and a more mixed economy of small game, fish, seasonally wild vegetables and harvested plant foods. Many groups continued to hunt big game but their hunting traditions became more varied and meat procurement methods more sophisticated. The placement of artifacts and materials within an Archaic burial site indicated social differentiation based upon status in some groups.
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^"Introduction". Government of Canada. Parks Canada. 2009. Archived from the original on 2011-04-24. Retrieved 2010-01-09. Canada's oldest known home is a cave in Yukon occupied not 12,000 years ago as at U.S. sites, but at least 20,000 years ago
^"Pleistocene Archaeology of the Old Crow Flats". Vuntut National Park of Canada. 2008. Archived from the original on 2008-10-22. Retrieved 2010-01-10. However, despite the lack of this conclusive and widespread evidence, there are suggestions of human occupation in the northern Yukon about 24,000 years ago, and hints of the presence of humans in the Old Crow Basin as far back as about 40,000 years ago.
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^McMenamin, M. A. S. (2011). "A recycled small Cumberland-Barnes Palaeoindian biface projectile point from southeastern Connecticut". Bulletin of the Massachusetts Archaeological Society. 72 (2): 70–73.
^deFrance, Susan D.; Keefer, David K.; Richardson, James B.; Alvarez, Adan U. (2010). "Late Paleo-Indian Coastal Foragers: Specialized Extractive". Latin American Antiquity. 12 (4): 413–426. doi:10.2307/972087. JSTOR972087.
^Zegura SL, Karafet TM, Zhivotovsky LA, Hammer MF (January 2004). "High-resolution SNPs and microsatellite haplotypes point to a single, recent entry of Native American Y chromosomes into the Americas". Molecular Biology and Evolution. 21 (1): 164–75. doi:10.1093/molbev/msh009. PMID14595095.
^Saillard, Juliette; Forster, Peter; Lynnerup, Niels; Bandelt, Hans-Jürgen; Nørby, Søren (2000). "mtDNA Variation among Greenland Eskimos. The Edge of the Beringian Expansion". Laboratory of Biological Anthropology, Institute of Forensic Medicine, University of Copenhagen, Copenhagen, McDonald Institute for Archaeological Research, University of Cambridge, Cambridge, University of Hamburg, Hamburg. Retrieved 2009-11-22.