Capybaras are the largest living rodent, and very likely the only rodent to be officially declared a fish. Adult capybaras will reach the mass of a man. They are semi-aquatic, spending most of their time in or near water and grasses and aquatic plants as well as fruit and tree bark. Because they cannot digest all of their food in one pass, they will eat their feces to digest it again on a second go-through.
Capybaras live in groups of 10 to 20 individuals, and may congregate in herds of up to 100 in the dry season. One male will be dominant, and will usually be found near the center of the group. They chatter to each other to keep in touch, make friends, or signal dominance. In addition, they also communicate by scent marking and urinating. Threatened capybaras may bark, reminiscent of a dog.
Capybara are found in most of South America east of the Andes, except for south and west Argentina. There may be a feral population breeding in Florida.
And about being officially declared a fish - because capybaras spend so much time in the water, the Catholic Church has allowed them to be eaten during lent by declaring them a fish.