In economic, sociological, and mythological terms the Chamacoco are a symbiosis of very primitive hunters and gatherers—similar to those of Tierra del Fuego—but hunters with a dual organization and incipient agriculture, resembling the Gê of eastern Brazil and Mato Grosso. Present in Chamacoco culture are possibly also certain influences of the somewhat more intensive agriculturists of the plains of Chiquitos. First contacts with the Europeans occurred about the end of the eighteenth century, but simultaneously the Chamacoco were strongly influenced by the Kadiwéu whom they met on their journey to the Río Paraguay. Aside from imposing a regular tribute of slaves—and thus establishing a typical intertribal system—the Kadiwéu imparted to them some features of their political style, which was strongly martial and based on endogamous castes. Consequently, in addition to waging wars against neighboring tribes to capture slaves for their masters, the Chamacoco quickly learned to use the slaves for their own benefit, and, with their own rules of clan organization slackening, they also accepted the rudiments of hierarchic stratification and intertribal marriage.
Around 1800, following the definitive occupation of their territory by Whites, the massive assimilation of the Chamacoco as salaried workers in the lumber industry and in ranching and the total overhaul of the Chamacoco tribal economy began. Although various social and political customs endured, albeit in a greatly altered form, the inception, in 1955, of the activities of the New Tribes Mission brought an end to the boys' initiation ritual and pertaining practices among the Hório-Ebidóso. Only among the Tomaráho subgroup are these still performed. Yet, at about the same time, the state of Paraguay ceded to the Chamacoco a reservation zone in Puerto Esperanza, an area more or less distant from Whites, where a major portion of the Ebidóso and almost the entire group of Tomaráho were concentrated. This important event had an invigorating effect on the faltering institution of youth initiation.