chloelove, how old are your cats? It sounds as though they are not too old, perhaps less than 1 year. Generally, a pet cat can be taught not to bite, but it requires some patience and time. I notice with mine that when they bite, usually when playing or if they are new to the pride, that if I allow whatever it is that they bite, to go limp, they usually get the message. Also, if I verbally protest their biting they will usually stop it. The only one who hasn't learned not to bite when I pet him is Fawn, a mostly Abyssinian, but he doesn't bite as hard as he did in the past.