This rodent, Coelogenys (or Agouti) paca, together with one or two other tropical American species, represents a genus near akin to the agoutis and included in the family Caviidae.
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.
Capybaras belong to the family Caviidae, the leading characteristics of which are given in Rodentia.
In the family Caviidae, typified by the cavies (or guinea-pigs), may be included a large number of South and Central American rodents, among which the agoutis and pacas are often ranked as a family (Dasyproctidae) by themselves.
The Caviidae, in the present more comprehensive sense, include the giants of the rodent order.