Plains viscachas are large, somewhat rabbit-like rodents with striped faces from the southern plains and scrublands of South America. The males are about four times as large as the females. Nevertheless, the females are the core of the plains viscasha society, living in matriarchal groups within extensive burrow systems that they excavate. The males are transient, staying for a year before moving on. During a male's year long residence, he may be displaced by other wandering males by violence and often spends much of his time defending his females. Males also defend against predators, typically by standing watch and giving alarm - a "wank" sound - if they see danger.
Plains viscacha burrows, called viscacheras, may cover 600 square meters and may contain dozens of entrances. Some entrances are so large and deep that a person can stand in them up to his waist. Most entrances are plugged, only a few remain active at any time. Smaller satellite viscacheras are made for emergency refuge when colony members are caught off guard away from their main burrow system.
Plains viscachas are nocturnal and herbivorous, typically eating seeds and grass but are willing to eat nearly any vehetation.