A large hornless ruminant quadruped with a humped back, long neck, and cushioned feet. It is domesticated as the main beast of burden in arid regions of western Asia and northern Africa. There are two distinct species, the Arabian or one-humped, and the Bactrian or two-humped. A lighter and faster variety of the Arabian is known as the dromedary. The Bactrian was fully domesticated by the 1st millennium BC and evidence of their existence dates to the first half of 3rd millennium BC. There are four camelids found in the Andes of Peru - the vicuna, guanaco, llama, and alpaca. The first two are wild, the last two domesticated. Cave excavations yield bones from c 8000-1000 BC with herding evidence c 3000-2000 BC and pack animal use between 600-1000 AD.