People are telling you really good stuff here.
We used to have 12 ferrets and sent them to a rescue because we couldn't take them when we moved. The rescue was really good about when we explained the situation. We wanted to keep the little buggers.
The only animal that will bite, reguardless of type of animal, is one that is mistreated in someway. Ferrets can get rough playing and bite and it does hurt, but you have to understand, it wouldn't hurt another ferret if it were a ferret they were playing with, they have much thicker skin than you or I.
I would like to say that I am the resdedent ferret expert because of my schooling and experience but there are a couple people on here that probably know more than I do because they run rescues and/or breed them.