The history of the Great Plains Indians can be traced back at least 13,000 years and possibly even millenia. During the last stages of the Ice Age, small bands of people migrated in search of megafauna, or game, such as mastodons and mammoths. As game became extinct, their cultural organization became more complex, shifting to bison hunting and living in earth-lodge dwellings. However, European contact brought much change. Prior to this contact, tribes of the plains lived by agriculture or gathering. The introduction of horses by the Spanish in the late 16th century provided Indians with a more efficient method of hunting buffalo. Many groups--the Kiowa, Cheyenne, Sioux, Comanche and others--shifted to a nomadic culture. Portable tipis, immense value placed on horses, and the accumulation of herds were common patterns among these groups. Others such as the Mandans, Arikara, Hidatsas, Pawnee, Wichita and Omaha remained horticultural societies, establishing permanent settlements in the river valleys of the plains. Source: Lewis and Clark Expedition, National Park Service.
According to the 2010 Census, 5.2 million people in the United States identified as American Indian and Alaska Native, either alone or in combination with one or more other races. Out of this total, 2.9 million people identified as American Indian and Alaska Native alone. Almost half of the American Indian and Alaska Native population, or 2.3 million people, reported being American Indian and Alaska Native in combination with one or more other races. The American Indian and Alaska Native in combination population experienced rapid growth, increasing by 39 percent since 2000. Source: The American Indian and Alaska Native Population: 2010