Intergroup and Intragroup Spacing in the Plains Vizcacha, Lagostomus maximus

Direct observations and radiotelemetry were used to study spatial organization of the plains vizcacha (Lagostomus maximus) in semi-arid scrub of La Pampa Province, Argentina. Vizcachas live in social groups, the members of which share a communal burrow system and a common home range. Although home range boundaries are not defended, little overlap occurs between home ranges of neighboring groups. All sex and age classes defend the communal burrow system by chasing intruders. Adult males advertise occupancy of the home range with vocalizations and scent marks. Vocalizations were given most frequently during spring, when new immigrants began dispersing into the burrow systems; scentmarking and chases were most frequent during the breeding season. These behaviors occur primarily at burrows.