A preliminary field investigation of the yellow handed titi monkey, Callicebus torquatus torquatus, in Northern Peru

A three month field study was conducted on Callicebus torquatus near the Nanay River in northern Peru. Data were collected primarily by the time sampling method. Information on daily movement, vocalizations, population density, and social behavior is presented. The titi monkeys we studied have a family unit pattern of social organization, territoriality accompanied by vocal activity, and a home range of about 20 hectares. There is a high degree of parental investment in care of the infant on the part of the adult male.