: any of several short-tailed South American rodents (family Caviidae); especially:guinea pig
Patagonian cavy, or mara (Dolichotis patagona).—George HoltonPhoto Researchers
Any of several species of South American rodents constituting the family Caviidae. Species in the genera Cavia, Kerodon, Galea, and Microcavia resemble the guinea pig. They are stout, gray or brown, and 10–12 in. (25–30 cm) long, with short ears and legs and no visible tail. The Patagonian and salt desert cavies (Dolichotis) are more long-legged and rabbitlike. Cavies are social animals found in various habitats, including plains, marshes, and rocky areas. They live in burrows (which sometimes weaken the ground above so much that it collapses when walked on), and they feed on grass, leaves, and other vegetation.