 Members of the Masco-Piro living in voluntary isolation today are thought to be related to members of the Masco-Piro groups who fled local rubber barons before enslavement or after they attacked the rubber barons for being mistreated and later fled into the forests to avoid persecution.The Masco-Piro language is part of the Arawak and the Amahuaca is part of the Pano linguistic family.The Masco-Piro live on the tributaries of the Manu, Los Amigos, Las Piedras, and Tahuamanu Rivers (Castillo 2004).