Amerindian peoples of the pampas, such as the Puelche and Tehuelche, adopted the Mapudungun language as their main language (both of their names are in Mapudungun).
American researcher Junius Bird and Finnish geographer Väinö Auer confirmed the existence of a Tehuelche prototype who lived in the sands of Rada Tilly some 9000 years ago.
Native Argentines on the other hand have significant populations in the country's North-West (Quechua, Diaguita, Kolla, Aymara); in the North-East (Guaraní, Mocoví, Toba, Wichí); and in the Patagonia or South (Mapuche, Tehuelche).
On the way they met an army contingent escorting Tehuelche prisoners to Valcheta, part of one of the last campaigns in the Conquest of the Desert.