Archaeologists have done little research in the Yanomamö area. Ethnographers believe that the homeland of the Yanomamö lies in the Parima highlands of the VenezuelanBrazilian border, and that they have recently expanded from there as a result of the decimation of Carib speakers who occupied the upper Orinoco and its major tributaries. Initial contact with Westerners may have begun as early as the mid-1750s, but it was not until the mid-1950s that missionaries and anthropologists made sustained contact. Some Yanomamö have had sustained contact with the Yekuana Indians for at least a hundred years, which has led to warfare, intermarriage, and establishment of partially integrated cosettlements. The contact situation differs sharply between the Brazilian and Venezuelan Yanomamö. In Venezuela, Yanomamö interaction with foreigners is largely limited to Yekuana Indians, missionaries, anthropologists, and government workers. In Brazil, significant portions of Yanomamö lands have been invaded by miners, which has led to the introduction of a variety of diseases that have taken a huge toll in Yanomamö lives and, in some places, open warfare occurs between the Yanomamö and Brazilians.