Relatively barren foothills of the Andes at elevations of 3,000 to 5,000 meters and in the coastal mountains of Chile, sheltering in crevices and holes among the rocks. Strictly herbivorous, eating any available vegetation. Colonial, formerly found in groups of about 100 individuals. Earlier reports of monogamy probably erroneous. Gives birth to two or three exceedingly precocial young weighing about 35 g. each.
Lactation lasts between six and eight weeks.
Both males and females become fertile at about eight months of age. Life span is 10 years in the wild, twice that in captivity. Dense fur indicates the depth of cold at the altitudes they inhabit. This fur has led to their extirpation. Feet adept at jumping, clinging and climbing over rocks.