I have heard stories of male cats jumping on pregnant female cats' stomachs, attempting to kill her unborn kittens. Do male cats know if a litter of unborn kittens belong to another male? I know that males will kill the kittens of another male to ensure that he'd father the female's next litter. Do males know if a litter of kittens are his or not by their smell? I am just wondering this because I don't think that a male would know before the kittens are even born.