Rodents comprising the family Caviidae, which includes the guinea pig, rock cavies, mountain cavies, capybara, salt-desert cavy, and mara. All members of the group are indigenous to South America and comprise 15 species in six genera. Cavies have either rounded bodies with large heads and short ears and limbs, or rabbitlike bodies with long limbs and moderately long ears. They have 20 teeth with short incisors and a dental formula of I 1/1 C 0/0 Pm 1/1 M 3/3.