land on both sides of the border of brazil and venezuela has long been occupied by the yanomamo people. these "fierce people" are the last stone age tribe left in south america. following discovery of gold, approximately 45,000 garimpeiros (gold miners) invaded the yanomamo territory. the mining process pollutes the rivers and scares away game, so traditional yanomamo sources of food are almost impossible to find now. the yanomamo are starving. economists call this problem