Atsina: An inaccurate and derrogatory name for a Native American tribe located in northcentral Montana commonly known as the Gros Ventre. There are currently 5000 members, and they share Fort Belknap Indian Reservation with the Assiniboine; their historical enemies. Gros Ventre is a name that was given to the people by the French who mis-interpreted thier sign language. Instead, the Gros Ventre people refer to themselves as A'ani or A'aninin which means, "white clay people".
The Gros Ventre of the Prairies, the Atsina, originally were part of the Arapaho, according to historians.
As a result of the split the Crow Indians have at different times been known as the Gros Ventre of the Prairies to distinguish them from the other half of the tribe, the Gros Ventre of the Missouri.
The Gros Ventre of the Prairies were the Atsina, and soon the name ceased to apply to the Crow.
Hidatsa, or Minitari, of Siouan stock; and the Algonquian Atsina, an offshoot of the
Mandan, Hidatsa, and Arikara tribes, also known as the “Three Affiliated Tribes.” The Atsina, to whom the name Gros Ventre is now generally applied and who call themselves Aani, “White Clay People,” are settled in Montana on Fort Belknap Reservation, which was established in 1888 and is also home to the Assiniboine, or Nakoda, people.
The 2000 census recorded separately the Atsina (pop., 8), the Gros Ventres proper (1573), and the Fort Belknap Gros Ventres (1300), with a total population of 2881.