The degu (Octodon degus, /ˈdeɪɡuː/) is a small caviomorph rodent endemic to the Chilean matorral ecoregion of central Chile. It is sometimes referred to as the brush-tailed rat, and is also called the common degu, to distinguish it from the other members of the genus Octodon. Other members are also called degus, but they are distinguished by additional names. The name "degu" on its own, however, indicates either the genus Octodon or, more usually, O. degus. Degus are in the parvorder Caviomorpha of the infraorder Hystricognathi, along with the chinchilla and guinea pig. The word degu comes from the Mapudungun dewü (mouse, rat).