The Algonquian-speaking Gros Ventre Indian tribe occupies the Fort Belknap Reservation, which it shares with the Assiniboines in north central Montana. There are approximately three thousand enrolled Gros Ventres, with 1,385 members residing on the reservation. The tribe has been referred to by many inaccurate names throughout history, including Rapid Indians, Waterfall Indians, Big Bellies, Willow Indians, Atsinas, and Gros Ventres of the Prairie. Scholars and early explorers have often confused the Gros Ventres of the River, also known as the Hidatsas, with the Gros Ventres of Fort Belknap. The Gros Ventres of Fort Belknap refer to themselves as the A'ani', "White Clay People."
The religious structure of the A'ani' is similar to that of many tribes of the northern plains. Their most important ceremony, the Sun Dance, was held during the summer months. The introduction of Catholicism into the tribe devastated much A'ani' culture, with only a few remnants surviving today. Two pipes form the spiritual center of the tribe: the Flat Pipe and the Feathered Pipe. These have been regarded as communally sacred for centuries.
A'ani' and Arapaho oral tradition tells that the two tribes were once joined, living on the Canadian plains, and that they parted company around the Red River in 1700. The earliest known document describing contact of A'ani' with white traders dates from 1754 and establishes the tribe on the vast plains between the north and south branches of the Saskatchewan River. It was there that the A'ani' resided until the smallpox epidemic of 1780, which drastically reduced their numbers. At the same time the A'ani' were being pushed south by the well-armed Crees and Assiniboines. In 1793 and 1794 the A'ani' burned down two trading posts in their territory, hoping to cut off the flow of arms to the Crees and Assiniboines.
In 1826, half of the A'ani' rejoined the Arapahos and went south to trade with the Mexicans. After many skirmishes, these A'ani' returned to Montana. On their return trip, they rendezvoused with white trappers and Flatheads in southeastern Idaho. The trading among them had gone awry, and the A'ani' fought the trappers and the Flatheads at what today is known as Pierre's Hole.
After the tribe reunited in central Montana, several explorers and artists met the A'ani' and recorded their wealth. Prince Maximilian and the artist Karl Bodmer met them in 1833 at the confluence of the Arrow and Missouri Rivers, where Bodmer painted portraits of several A'ani' people.
The smallpox epidemic of 1837 was devastating for many tribes of the northern plains; fortunately, the A'ani' suffered relatively few losses because of their earlier exposure to smallpox. But the A'ani' were feeling increasing pressure from the Crows, and they decided to join forces with the Blackfeet. The Blackfeet and the A'ani' signed a treaty with the federal government in 1855 establishing common hunting grounds and a yearly distribution of provisions. The A'ani' later split with the Blackfeet, and in 1888 Fort Belknap was established as their home. In 1895, with the buffalo herds declining because of the railroads and the activities of white buffalo hunters, the A'ani' population reached its all-time low: 596 members