During the day, the southern viscacha emerges from the clefts and crevices it colonises, to forage for food, and bask on rocky perches in the sun (1) (3) (4). It runs and leaps amongst the rocks with incredible agility, and eats a wide variety of plants including grasses, mosses, and lichens (3) (4). Like all mountain viscachas, the southern viscacha is a gregarious species that forms small to very large colonies, comprising one or more family groups (4) (5). The timing of the breeding season is not documented for this species, but the gestation period has been estimated at 120 to 140 days, with just a single young born at a time. The young is born fully haired with its eyes open, and is normally weaned after eight weeks, and reaches sexual maturity at around a year (3).