Ecology and Social Behavior of the Desert Cavy (Microcavia australis)

Abstract

The behavior and ecology of a population of individual- ly marked Microcavia australis was studied in a xerophytic thornbush habitat in Buenos Aires Province, Argentina, from April 1966 to Octo- ber 1967. Another cavy, Galea musteloides, occurred in smaller numbers on the study area. Interactions between the two genera were amicable. Microcavia births occurred from August to April with most litters born in the September-December period. Gestation was 54 days. One female gave birth to four litters during the breeding season. Adult males have home ranges of approximately ?4 hectare, about twice the size of female home ranges. Microcavia is diurnal and may be active at any time of day. Most social interactions occur in the bare areas surrounding thorn- bush associations. Communal rolling sites are loci for olfactory com- munication. Interactions between adult males are agonistic and orga- nized by a straight-line dominance hierarchy. Males congregate around the home bush of a female near term; a conspicuous mating chase occurs at the post-partum estrus. Juveniles may suckle from lactating females other than the mother. Adult males associate with juveniles and respond sexually to them. Females maintain amicable relations with their daugh- ters until the birth of the next litter. Many behavioral similarities be- tween Microcavia and sciurid ecological equivalents, such as Citellus and Cynomys, are convergently evolved adaptations to open habitats. Microcavia social organization is more similar to that of rabbits (which also have a high reproductive potential and high mortality rate) than to sciurid ecological equivalents.