Viscacheras are valuable resources for L. maximus , as they protect the members from predators and provide sanctuaries for mating, birthing and raising young. The long term social unit is the female-bonded group. Females reside in viscacheras when no males are present and continue to remain there through a series of males. Under stable conditions, closed matriarchal societies exist in which maturing females are recruited into their natal burrow systems. Females are thus permanent tenants of the viscacheras, and adult males disperse annually to different communities.
Males gain access to burrow systems only through contest competition.
However, natal dispersers and resident males from the previous year leave the viscacheras without contest competition with male immigrants. Contests among immigrant males occur six months before breeding and continue throughout the breeding season. Due to dispersal and mortality associated with competition, there is a high turn-over rate of males. The majority of scars on males are attributed to same-sex violent encounters. An exception to the above matriarchal system occurs during a population crash.