From the TV.com site trivia: "The helper monkey is a Capuchin monkey. While they are small, they can actually be quite dangerous. Both male and females of the species get violent when they reach sexual maturity if they are not able to mate. Though small, they possess incredible strength in proportion to their size. There are many cases of owners being severely bitten or attacked, even by monkeys they've raised. If they do become aggressive, like all monkeys, they tend to lunge for the face and throat. There have been documented cases of noses and fingers being bitten off. They are quite capable, as was shown in the episode, of wielding objects as weapons. Though it is not the norm, once this monkey began to exhibit violent tendencies, Craig had every reason to be afraid."
