NEZ PERCE (NIIMÍIPUU) RELIGIOUS TRADITIONS. The Nez Perce people are one of two Sahaptian-speaking groups—the Nez Perce and the Sahaptin—to inhabit the southern Columbia Plateau region of western North America. Aboriginally, the Nez Perce–speaking peoples are ancient occupants of the southern Columbia Plateau whose ancestral lands extend along middle Snake River in Oregon, Washington, and Idaho. The Nez Perce, as well as other Sahaptin groups, report no migration tradition placing them outside their current ancestral homelands; instead, their oral traditions contain imagery of mammoths, ice-age phenomena, and ancient volcanic activity. At the time of contact, the Nez Perce were composed of an estimated forty independent bands and were dispersed along three major tributaries of the Snake River: the Grande Ronde River (Oregon), the Clearwater River (Idaho), and the Salmon River...