I have two cats one male one female. The cats are brother and sister about six years old. The male cat is about fifteen pounds and the female is about seven and much smaller. The female was the runt of the litter and the male has been her protector from the time they were kittens. If we take the female to the kitchen to give her flea medicine or to trim her claws the male is right there to make sure we are not hurting her. They play together alot but latley the male has been very ruff and pins the female to the ground biteing her neck untill she criies and we come and save her. what we want to know is will he go to far and kill her and is he doing this when we are not home to save her.