Physical anthropology; primary interests in the evolution of behavior, specifically the behavior of the nonhuman primates. Special interests in ecology, primate conservation, and the evolution of sexual strategies. Research includes fieldwork with free-ranging olive baboons (Papio anubis) near Gilgil, Kenya, between 1970 and 1980, a nine-month survey of large mammals (including eight primate species) in the proposed Outamba-Kilimi National Park in Sierra Leone, West Africa in 1981-1982, and a study of mating strategies in a free-ranging troop of patas monkeys (Erythrocebus patas) on the Laikipia Plateau, Kenya. Studied wedge-capped capuchin monkeys (Cebus olivaceus) at Hato Pinero , in the Venezuelan llanos, between 1988 and 1995.