American anthropologist with extensive fieldwork (more than 60 months) among the Yanomamö of the Amazon Basin. His studies focus on warfare, violence, kinship, as well as on biological determinants of human sociality. His work became the subject of an extensive and bitter debate in American anthropology during the 1990's, when a number of serious accusations of ethical breaches were levelled at him. Chagnon has denied these; and the debate is still unresolved.