Our female cat would bite my whole family for no reason! She would even go up to the dog and bite him for no reason too! When she was 18 months we got a kitten. I think Belle was just bored and needed someone to play with, she hasn't biten the family or even the dog since we got Cuddles a year ago. They play together all the time and Belle is alot more loving to us now too! Maybe your kitty needs a friend!