Identification. The name "Xamicoco" or "Xamacoco," recognized since the latter part of the 1700s among the probable ancestors of the present Chamacoco, is of obscure origin. Its degree of acceptance by the Indians is also unknown, although they prefer the name "Ishír." The designation "Chamacoco" is probably related to "Chamóc" or "Zamúc," the ethnonym of a group of the Zamuco Family.
Location. At the beginning of the nineteenth century, the Chamacoco occupied the northeastern corner of the Chaco Boreal, in the arid zone of Cerro San Miguel and the headwaters of the Río Verde in Paraguay. The retreat of the Mbayá-Kadiwéu to the eastern shores of the Río Paraguay allowed the Chamacoco to relocate up to the western shores of that river between Bahía Negra and Fuerte Olimpo (20° to 22° N); they retained the southern portion of the hinterlands from 40 to 50 kilometers to the coast.
Linguistic Affiliation. The Chamacoco language belongs to the Zamuco Language Family. As a consequence of sociopolitical factionalization and reciprocal hostility, four dialects can be distinguished: Ebidóso and Hório, in the Bahía Negra region; Héiwo, in the Fuerte Olimpo area; and Tomaráho, in the interior forested zones.
Demography. In 1970 it was estimated that the combined Hório- and Ebidóso-speaking groups numbered 800 persons, whereas the Tomaráho did not exceed 200. Around 1930, however, the total Chamacoco population is believed to have been more than 2,000.