After encountering Dipper Pines, they have him perform rituals in order to become "man". As a final step, they send him out to kill the Multi-Bear. On his quest, however, Dipper discovers the Multi-Bear is actually a victim of the Manotaurs' harrassment because he wasn't considered "manly". Sharing something in common, Dipper decided to spare the Multi-Bear and abandon the Manotaurs.
The known manotaurs include Testosteraur, Pubertaur, Pituitaur, Chutzpar, Beardy, Clark, an old manotaur given as an offering, and their leader Leaderaur.