crab-eating fox, (Cerdocyon thous), South American member of the dog family (Canidae), found in grassy or forested areas. It attains a length of 60–70 cm (24–28 inches), excluding a 30-cm tail, and has a gray to brown coat that is frequently tinged with yellow. It generally lives alone or in pairs and spends the day in a burrow, emerging at night to hunt for such foods as small animals, fruit, insects, turtle eggs, and fowl. It is easily tamed and is sometimes kept as a pet.