Octodontidae

Octodontidae 

a family of mammals of the order Rodentia. Octodont rodents resemble rats. They have small, bare ears and solid brown coloration. The body length is up to 19.5 cm, and the tail length reaches 18 cm. The teeth, which have no roots, grow constantly.

There are five genera of octodont rodents, embracing eight species. They inhabit the western part of South America, from Argentina to Patagonia, where they are encountered in coastal regions and in mountainous areas with elevations to 3,500 m. The animals are active at twilight and at night. Most species live in burrows of their own construction. The most common species is the degus (Octodont degus), which sometimes damages agricultural crops.

Fossil remains of octodont rodents are known from the Oligocene. Five other genera, including Myocaster, which are separated by some zoologists into the family Capromyidae, are sometimes assigned to the family Octodontidae.