The Short-tailed chinchilla is one of two chinchilla species, along with the Long-tailed chinchilla. This rodent has a bushy tail, soft coat and considerably large ears. The color of their fur varies from blue-grey to pearl or grey. The under-part is yellow or off white. Chinchilla's coat is very thick, preventing evaporation of water and allowing the animal to endure cold temperatures. The feet are large, possessing weak claws and large pads. These rodents construct their dens in rock crevices, easily moving over rocks due to their foot pads, which prevent slipping.
The Short-tailed chinchillas come out of their dens at dusk and dawn in order to take sunbaths. They are able to navigate during the night due to their vibrissae. These rodents are highly sociable animals, forming either small groups of a few individuals or large ones, consisting of over a hundred animals. Females of this species are a bit larger than males. Hence, they try to establish dominance over the group. During the daytime hours, these nocturnal animals rest in secluded places, typically in rock crevices or small holes in rocks. These animals mainly communicate through vocalizations. When threatened, chinchillas growl, chatter their teeth or give out a long warning cry, which is similar to a whistle and acts as an alarm call. Other common calls include a low cooing noise and aggressive hiss-and-spit sound.
Short-tailed chinchillas are herbivores. Their diet consists of grasses, herbs and any vegetation, found in their ecosystem. They are known to supplement this diet with various insects. Moisture is usually obtained from the flesh and fruit of cacti. Meanwhile, those living in dry environment, get required moisture form the morning dew.
These rodents are likely to have a monogamous mating system. However, their colonies vary in size greatly, which doesn't allow to determine their bonding status. Mating occurs year-round. Gestation period lasts for 128 days, yielding 1 - 2 young. Females usually produce 1 - 2, occasionally 3, litters par year and can mate again a week after producing offspring. Newborn chinchillas are capable of eating plant food and are born their fur, teeth and open eyes. As soon as babies emerge, the mother dries them and the young creep under her body. Young chinchillas are weaned at 6 weeks old, reaching sexual maturity at 5.5 - 8 months old.
Currently, the biggest threat to the population of this species is illegal hunting: chinchillas are highly profitable, attracting hunters for their fur and meat. These rodents are bred in captivity for pet trade and for fur. They suffer from predation by foxes and compete with grazers such as goats and cattle. On the other hand, the Short-tailed chinchillas are potentially threatened by mining, firewood extraction and other human activities. Other potential threats include burning and harvesting of the algarrobilla shrub, which is their natural habitat. And finally, this Critically Endangered species has a very total small population, which can go extinct due to long-term environmental changes.
The IUCN Red List and other sources don’t provide the number of the Short-tailed chinchillas’ total population. Today, this species’ numbers are decreasing, and the animals are classified as Endangered (EN) on the IUCN Red List.