Closely allied to the porcupines are the gregarious viscachas of the South American plains, that live in "villages" of burrows, and much resemble prairie dogs in appearance and habits; also the chinchillas of the high levels of the Andes, whose soft gray coat is one of the prizes of the furrier. Here, too, come the swift-footed, slender agoutis and pacas of South America, many species of which exist and are useful as food; and a neighboring family contains the little cavies, from one of which are derived our pet "guinea pigs," which are not pigs and do not come from Guinea; also their cousin, the almost aquatic capybara, which measures three feet long, and so is the biggest known rodent. This is much hunted for its flesh, and is the principal prey of the jaguar.