The alpaca is a domestic camelid from South America.
The alpaca is the domesticated version of the wild vicuña, but people did not always think so. Previously alpacas were believed to be more closely related to llamas. In fact alpacas, llamas and vicuñas were though to be more closely related than they are, but modern DNA tests showed enough differences to justify why vicuñas and their domesticated descendants the alpacas are now classified in the genus Vicugna which is distinct from the genus Lama.
Alpacas, just like their cousins the llamas, can sometimes spit on you it you go too close. This is a protection mechanism. The spit is usually not just saliva but stuff from the alpaca’s stomach. But they don’t necessarily do so, and I was able to take a close up picture without having alpaca stomach content all over me.
The primary value of the domestic alpaca is its wool which is considered to be superior to sheep’s wool. One can only guess that because vicuña wool was already highly priced since ancient times in South America it was just less hassle to domesticate the beasts than to capture them every couple of years for sheering.