Plains viscachas live in communal burrow systems in groups containing one or more males, several females and immatures. Viscachas forage in groups at night and aggregate underground during the day. All members of a group use burrows throughout the communual burrow system and participate in digging at the burrows. Alarm calls are given primarily by adult males. Allogrooming occurs among all sex-age classes within a social group but not between members of different social groups. Agonistic interactions occur more often between members of different social groups than within a group.
The long-term social unit of the plains viscacha is the female group. Resident males disappear each year and new males join groups of females. Dominance is absent among females. Agonistic interactions are rare among adult males within a social group and dominance is not clearly evident.