| Caviidae - Cavies | |||
| Subfamily - Caviinae | |||
| Brazilian Guinea Pig | Cavia aperea pamparum | ||
| Southern Mountain Cavy | Microcavia australis australis | ||
| Subfamily - Dolichotinae | |||
| Patagonian Mara | Dolichotis patagonum patagonum | endemic to Argentina | |
| Subfamily - Hydrochoerinae | |||
| Capybara | Hydrochoerus hydrochaeris | monotypic | |