Capybara, (genus Hydrochoerus), also called carpincho or water hog, either of two species of large semiaquatic South American rodents. Capybaras inhabit forests and wetlands from Panama to Argentina. The larger of the two species, the capybara (Hydrochoerus hydrochaeris), is the largest living rodent in the world, growing up to about 1.3 metres (4.3 feet) long and weighing up to 79 kg (174 pounds).