Sirionó

The Sirionó, who call themselves Mbía, 'the people', are a small Tupí-Guaraní-speaking nation of eastern Beni and northwestern Santa Cruz in the Bolivian lowlands, best known today for the community of Ibiato. Their ancestors moved north from the Gran Chaco region into the Amazonian forests, and until the twentieth century they lived as highly mobile bow hunters, foragers and part-time farmers of maize, sweet potato and cassava; a whistled speech register has even been recorded among them.

Epidemics, ranching expansion and forced settlement on missions and haciendas devastated the people in the early 1900s, and Allan Holmberg's 1950 ethnography made them famous, and controversially so, as supposedly 'deprived' nomads, a portrayal later scholarship has firmly revised. From roughly 133 self-identified members in 2001, census figures rebounded to 782 in 2012.

Modern Sirionó live in settled villages, farm rice, maize and bananas, sell honey and crafts such as hammocks and baskets, and work on surrounding ranches. They were protagonists of Bolivia's landmark 1990 March for Territory and Dignity and received one of the country's first titled Indigenous territories around Ibiato; language revitalization is now an urgent concern.