Guanaco, common name for a species of wild South American ruminant (cud-chewing mammal). The closely related alpaca and llama are completely domesticated; the related vicuna is found in South America. The guanaco is found on mountains and plains in Argentina, Bolivia, Chile, Peru, and Paraguay. The wild population is estimated to be about 600,000. The guanaco takes to water readily and has often been seen swimming from one island to another. A full-grown male stands 90 to 130 cm (35 to 51 in) high at the shoulder and is covered with a thick coat of long, soft, reddish-tan hair. The head is small, with pointed ears; the neck is long, with a graceful curve; and the legs are long and slender. The fur on the belly is pure white. Guanacos are fast-running animals, but often succumb to predators because of their curiosity. An entire group of about eight animals might be attracted to the actions of a hunter and will remain in the vicinity even after shots are fired. Guanacos are exploited for their wool and meat. Hunting and competition for pasture from cattle and sheep have led to a decline in the population of guanacos. Their dung is used for fuel, and it commonly accumulates in a distinctive ring about areas used repeatedly by the guanacos.

Scientific classification: The guanaco belongs to the family Camelidae. It is classified as Lama guanicoe.