The family Chinchillidae is in the order Rodentia and consists of the chinchillas, the viscachas, and their fossil relatives. This family is restricted to southern and western South America, mostly living in mountainous regions of the Andes but one species living on plains. They are medium to large-sized rodents, weighing from to , with strong hind legs and large ears and a bushy tail. All species have thick, soft fur, which is considered valuable in some cultures.