The llama, the guanaco, the vicuņa, and the alpaca are all closely related animals. The llama and the alpaca both have been domesticated while the guanaco and the vicuņa remain wild.
These four species do not belong to same genus. The llama and the guanaco belong to the genus Lama, while the vicuņa and the alpaca belong to the genus Vicugna. Both genera belong to the tribe Lamini in the family Camelidae.
The alpaca has recently been reclassified. Previously, the alpaca was thought to descend from the llama. Studies of alpaca DNA revealed that the alpaca descended from the vicuņa (Wheeler et al., 2001).