Native North Americans of the Plains whose language belongs to the Algonquian branch of the Algonquian-Wakashan linguistic stock. Their own name was Inuna-ina (our people), but they were referred to as dog eaters (for the obvious reason) by other Native Americans. Tradition places their early home in N Minnesota in the Red River valley, but nothing is known of the date or circumstances of their separation from other Algonquian peoples. They are thought to be most closely related to the Cheyenne and to the Blackfoot. However, it is known that the Arapaho divided into two groups after they migrated to the plains. One group, the Northern Arapaho, continued to live on the North Platte River in Wyoming, while the Southern Arapaho moved south to the Arkansas River in Colorado. Traditionally the Southern Arapaho were allied with the Cheyenne against the Pawnee. The Arapaho placed some emphasis on age grades, mainly for ceremonial purposes. Their annual sun dance was a major tribal event, and later the Arapaho adopted the Ghost Dance religion. There are three major divisions—the Atsina or Gros Ventre, who were allied with the Blackfoot and now live with the Assiniboin on the Fort Belknap Reservation in Montana; the Southern Arapaho, now living with the Cheyenne in Oklahoma; and the Northern Arapaho, who retain all of the sacred tribal stone articles and are considered by Native Americans to represent the parent group. Since 1876 they have lived on the Wind River Reservation in Wyoming with their former enemies, the Shoshone. See G. A. Dorsey and A. L. Kroeber, Traditions of the Arapaho (1903, repr. 1974); V. C. Trenholm, Arapahoes, Our People (1970).