Part of playing MMO’s like this is discovery.
Through exploration, questing, trying different things (and sometimes failing), you find out about things.
Going to sites like Wowhead is just you reading about other player’s experiences. Stuff on Wowhead is just the discovery that someone else already made, and posted their findings there.
You can find out things through trial and error (as the OP did about the alpaca) or you can research things that other players found about (possibly by trial and error).