The emergence of Plano culture in the Great Plains area marked the beginning of increasing Native American population density as a result of the more suitable climatic conditions that followed the warming of the post-Wisconsin glacial period.

The term “Plano” is derived from the Spanish word for plains, the region in which the Plano culture flourished after the huge ice sheets that had covered much of North America began to recede as the Wisconsin glacial period came to an end about 13,000 years ago. The effect of these climatic changes on the everyday life of the people who lived in the region is not fully understood and has been the subject of much scholarly debate. There is considerable disagreement over the proper placement of Plano culture within competing time periods. Although some scholars include Plano culture within the Paleo-Indian period, others argue that it is more suited to the beginning stage of the more contemporary Early Archaic period.

The people of the Plano cultures differed from their predecessors, the Folsom people, in a number of ways. The diversity of their use of resources was considerable and is indicated by broader subsistence patterns, including bison-based and more generalized hunter-gatherer patterns. They appear to have been much less nomadic than previous inhabitants of the region. Plano cultures also show evidence of organized hunting methods, including the herding of large numbers of bison off cliffs and into other topographic traps. Plano reliance on big-game hunting indicates that although their projectile points are found in mountainous areas, they were not frequent inhabitants of higher altitudes.

The plants and animals that inhabited the emerging grasslands of the Plano period provided a stable and readily available food supply for the people of the region, resulting in a dramatic increase in population. Caribou, in the northern plains, and bison, in the southern regions, served as year-round sources of food and clothing for the inhabitants. Evidence suggests that Plano culture may be best characterized as a collection of small, highly mobile groups whose subsistence was based on efficient utilization of available plant foods, such as sunflowers and berries, in combination with meat from large grazing mammals, fish, and small animals. Grinding tools found at Plano-era campsites indicate that grains were also part of their diet.

Anthropologists and archaeologists have divided Plano cultures into subcultures, most often based on the varied geographic and ecological locales inhabited, but all the subcultures share the distinctive method of chipping stone that produced projectile points that differed from the fluted points of earlier periods. The emergence and prolific use of projectile points corresponds with the increase of population throughout much of North America as the receding glaciers left grasslands that expanded northward in their wake.

The stable and readily available food supply, in combination with the production of more effective projectile points, resulted in a dramatic increase in population and perhaps life expectancy for the people of the Plano cultures. Plano peoples served as the evolutionary precursor for Early Archaic cultures, whose tools eventually became more varied and displayed greater technological innovation than those of their predecessors.

• Bower, John R. F., and Michal Kobusiewicz. Comparative Study of Prehistoric Foragers in Europe and North America: Cultural Responses to the End of the Ice Age. Lewiston, N.Y.: Edwin Mellen, 2002. A fascinating comparative look at the response of Americans and Europeans to the end of the Ice Age. Bibliography and index.
• Deller, D. Brian, and Christopher J. Ellis. An Early Paleo-Indian Site Near Parkhill, Ontario. Seattle: University of Washington Press, 2001. Provides details and analysis of the life of Paleo-Indians who were living near the Parkhill site in southern Ontario as the great ice sheets melted and caribou began to migrate through the area. Bibliography.
• Dyck, Ian G., and Richard E. Morlan. The Sjovold Site: A River Crossing Campsite in the Northern Plains. Hull, Quebec: Canadian Museum of Civilization, 1995. This fascinating work contains details of a site in Saskatchewan. Bibliography and index.
• Fagan, Brian M. Ancient North America: The Archaeology of a Continent. New York: Thames and Hudson, 2000. A narrative account of what is known of the diverse cultures of ancient North America. Bibliography and index.
• Frison, George C. Prehistoric Hunters of the High Plains. San Diego, Calif.: Academic Press, 1991. One of the most respected works about plains archaeology. Bibliography and index.
• Frison, George C., and Dennis J. Stanford. Agate Basin Site: A Record of the Paleo-Indian Occupation of the Northwestern High Plains. New York: Academic Press, 1997. Bibliography and index.
• Holliday, Vance. Paleo-Indian Geoarchaeology of the Southern High Plains. Austin: University of Texas Press, 1997. Provides detailed information about Paleo-Indian archaeological sites in northwestern Texas and eastern New Mexico. Southern High Plains sites are also compared with other sites across the Great Plains. Bibliography and index.
• Jablonski, Nina G., ed. The First Americans: The Pleistocene Colonizations of the New World. Memoirs of the California Academy of Sciences, no. 27. San Francisco: California Academy of Sciences and University of California Press, 2002. A collection of papers by well-known scholars who address theories about many of the unanswered questions about the arrival of modern humans in the Americas. Bibliography and index.
• Stone, Tammy. The Prehistory of Colorado and Adjacent Areas. Salt Lake City: University of Utah Press, 1999. Provides an interesting survey of Paleo-Indian culture in the region. Maps and illustrations. Bibliography and index.