The Arapaho (in French: Gens de Vache) tribe of Native Americans historically living on the eastern plains of Colorado and Wyoming. They were close allies of the Cheyenne tribe and loosely aligned with the Sioux Arapaho is an Algonquian language closely related to Gros Ventre, who are seen as an early offshoot of the Arapaho Blackfoot and Cheyenne are the other Algonquian languages on the Plains, but are quite different from Arapaho. By the 1850s, Arapaho bands separated into two tribes: the Northern Arapaho and Southern Arapaho. The Northern Arapaho Nation has lived since 1878, with the Eastern Shoshone on the Wind River Reservation, the third largest reservation in the United States. The Southern Arapaho Tribe lives with the Southern Cheyenne in Oklahoma. There is no direct historical or archaeological evidence to suggest how and when Arapaho bands entered the Plains culture area. The Arapaho Indian tribe most likely lived in Minnesota and North Dakota before entering the Plains. Before European expansion into the area, the Arapahos were living in South Dakota, Nebraska, Colorado, Wyoming, and Kansas. They lived in teepees which the women made from bison hide. Before they were sent to reservations, they migrated often chasing herds, so they had to design their teepees so that they could be transported easily. It is said that a whole village could pack up their homes and belongings and be ready to leave in only an hour. In winter the tribe split up into small camps sheltered in the foothills of the Rocky Mountains in present-day Colorado. In late spring they moved out onto the Plains into large camps to hunt buffalo gathering for the birthing seasonoun In mid-summer Arapahos traveled into the Parks region of Colorado to hunt mountain herds, returning onto the Plains in late summer to autumn for ceremonies and for collective hunts of herds gathering for the rutting seasonoun