Rabbits are clearly distinguished from hares in that rabbits are altricial, having young that are born blind and hairless. In contrast, hares are generally born with hair and are able to see (precocial). All rabbits except cottontail rabbits live underground in burrows or warrens, while hares live in simple nests above the ground (as do cottontail rabbits), and usually do not live in groups. Hares are generally larger than rabbits, with longer ears, and have black markings on their fur. Hares have not been domesticated, while European rabbits are often kept as house pets. In gardens, they are typically kept in hutches — small, wooden, house-like boxes — that protect the rabbits from the environment and predators.