Cavies in general, the more typical representatives of the Caviidae, are rodents with hooflike nails, four front and three hind toes, imperfect collar-bones, and the cheek-teeth divided by folds of enamel into transverse plates.
True cavies, or couies (Cavia), are best known by the guineapig, a domesticated and parti-coloured race derived from one of the wild species, all of which are uniformly coloured.
Cavies are widely distributed in South America, and are represented by several species.
As in the agoutis (Dasyproctidae), the milk-teeth are long retained,, while in the allied cavies (Caviidae) they are shed before birth.
The scapula is usually narrow, with a long acromion; the clavicles may be altogether absent or imperfect, as in porcupines, cavies and hares, but in most species are well developed.