Southern mountain cavies eat leaves, fruits and other plant material, with
mesquite and
Capparis being reported as particularly common foods. They can even climb trees to get at the leaves, sometimes reaching as high as above the ground. They live in colonial burrows with anything from 4 to 38 individuals. Such burrows can be extensive, with one being reported to have 26 entrances, and a total length of . They are
diurnal, emerging from the burrows at sunrise, and remaining active throughout the day, except in particularly hot weather. Males are often aggressive towards one another, creating a strict dominance hierarchy within the burrow. Nonetheless, in severe weather or when there are few shelter sites, individuals, especially females, may huddle together, and the females have also been seen to nurse young cooperatively. Natural predators include owls, hawks,
grisons, foxes, and skunks, and southern mountain cavies alert one another of danger with low-pitched alarm calls. Other calls include a high-pitched cry of fear and soft, almost inaudible, squeaks used during chases and courtship. Breeding occurs between August and April, with litters of one to five young being born about 54 days later. The young weigh about at birth, and are able to run almost immediately. They are weaned at around three weeks, and females may be sexually mature at just 40 to 50 days old. ==References==