guanaco (gwänäˈkō) [key] or huanaco hwänˈäko, wild mammal of the camel family, Lama guanicoe, found on arid plains in the Andes Mts. It is about 31/2 ft (105 cm) high at the shoulder, with a long neck; it is brown on the back and sides, with light underparts and a dark face. Although previously regarded by some authorities as the ancestor of the domestic llama and alpaca, genetic studies show that only the llama is descended from it. The guanaco is not domesticated, but indigenous South Americans use its flesh for food and make its hide into clothing and other coverings and its bones into various implements. Encroachments on its grazing land have reduced its numbers. The guanaco is classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Artiodactyla, family Camelidae.