Hydrochaeris

Hydrochaeris is a genus of large semiaquatic rodents in the family Caviidae. In many classifications, capybaras are placed in the genus Hydrochoerus; Hydrochaeris is an older spelling found in some sources.

Capybaras are the largest living rodents, with adults weighing up to 66 kg (145 pounds) and measuring about 1.2 meters (4 feet) in length. They have short, coarse fur that ranges from brown to reddish-brown, a blunt snout, and partially webbed hind feet suited to swimming.

They are native to tropical and subtropical South America, from Venezuela and the Guianas to Argentina, Bolivia, Brazil, and Uruguay. They inhabit savannas, marshes, riverside habitats, and wetlands and rely on water for thermoregulation and predator avoidance.

Capybaras are highly social and form groups of 10-20 individuals, with bachelor male groups and breeding units led by a dominant male. They are herbivorous, feeding on grasses and aquatic plants, and will also eat fruit and bark. They swim and rest in water to stay cool and avoid predators such as jaguars, caimans, and anacondas.

Breeding is typically year-round in favorable climates; gestation lasts about 150 days. Litter size ranges from 2 to 8 offspring, with rapid early development; young can walk within hours and are weaned at around two months.

The capybara is classified by the IUCN as Least Concern due to its wide distribution and large populations, though local threats include habitat loss and hunting for meat and skin.

The name capybara derives from Guarani or Tupi languages, and the term Hydrochaeris appears in older taxonomic literature.