Hydrochoerinae

Hydrochoerinae is a subfamily within the family Caviidae, in the order Rodentia. It encompasses the capybaras and their extinct relatives, and is distinguished from the other caviid subfamily by its members' adaptation to a semi-aquatic lifestyle. The only living genus in the subfamily is Hydrochoerus, with the capybara being the best known member. The capybara (Hydrochoerus hydrochaeris) is the largest living rodent and serves as the type species for the group. The subfamily also includes several extinct capybara lineages known from fossil records, indicating a broader historical diversity than is present today.

Living capybaras are large, herbivorous, semi-aquatic mammals native to South America. They possess a robust, barrel-shaped body, short limbs, and partially webbed feet adapted for swimming. Their fur is coarse and generally brownish. Capybaras form social groups that can include multiple adult pairs and their offspring, and they communicate with a variety of vocalizations and scent marking. They spend much of their time feeding on grasses and aquatic plants near rivers, lakes, and wetlands, and they are adept swimmers, often taking to the water to avoid predators or to forage.

Geographically, Hydrochoerinae members are now restricted mainly to South America, though fossil evidence indicates a wider past distribution, including parts of North America during the Pleistocene and earlier times. The subfamily traces its evolutionary roots to the Miocene, with a fossil record extending to the present, illustrating substantial changes in diversity and distribution over time.

Conservation status varies by species and region, but capybaras are generally listed as Least Concern, with local declines tied to habitat loss and hunting in some areas.