Chinchilla rats are members of the family Abrocomidae. They resemble Chinchillas in appearance, with a similar soft fur and silvery-grey color, but have a body-structure more like a short-tailed rat. They are social, tunnel-dwelling animals, and live in the Andes Mountains of South America. They are probably herbivorous, although this is not clear.
They can be described as medium sized. Stiff hairs project over the three middle digits of the rear feet. Their massive skulls narrow in the facial areas. Some molecular work , suggests that, despite their appearance, they may be more closely related to octodontoids such as degus, nutria, and tuco-tucos than they are to chinchillas and viscachas.