The alpaca (Lama pacos) is a species of South American camelid mammal. It is similar to, and often confused with, the llama. However, alpacas are often noticeably smaller than llamas. The two animals are closely related and can successfully crossbreed. Both species are believed to have been domesticated from their wild relatives, the vicuña and guanaco. There are two breeds of alpaca: the Suri alpaca and the Huacaya alpaca.
Alpacas can sometimes be aggressive, but they can also be very gentle, intelligent, and extremely observant. For the most part, alpacas are very quiet, but male alpacas are more energetic when they get involved in fighting with other alpacas. When they prey, they are cautious but also nervous when they feel any type of threat. They can feel threatened when a person or another alpaca comes up from behind them.[better source needed]