Why does my cat bite me when I pet it?
According to what I’ve read -Harrie, my feline roommate, bites too, so I had to inform myself-, there are three main explanations:
1.- Cats are hunters. When they are small, they instinctively learn to hunt and fight just like that: playing catch, ambush each other and bite each other. If you, while playing, always allowed him to bite you, your cat identifies the game that way. The game starts with petting and ends with biting, right? It is best to try to have toys that he can chase or catch, such as balls with jingle bells or feathered rods. If your cat, like Harrie, has learned to associate play with biting, the best thing to do is immediately stop petting and “ignore” him, letting him know that play is over when he bites. DON’T HIT HIM OR YELL, obviously he’s not doing it to hurt you on purpose. It is his natural instinct and a behavior that you should have corrected since childhood. Teach him to understand that the game does not involve biting or digging nails. It is very easy for a cat”lose control ” in those circumstances and believe me, it can cause you or others who ignore it, VERY painful injuries. From what I have observed, cats when they get a ” prey ” in this case your hand, grab it with their front claws to immobilize it, they bite it looking for soft parts -and their fangs are very sharp!-, and then they “tear” it with their hind legs, kicking it with everything and claws.
2.- You caress him in places he doesn’t like or you do it “wrong”, for example, against the grain. That bothers him. Stop doing it. For example, most cats love to be stroked on the head or along the back, or from the “chin” to the chest. Many hate it when you touch their hind legs, tail, or belly.
3.- It is possible that your cat feels pain when you touch it, if it is sick or has a problem. For example, if you try to touch his belly and he scratches, hisses, or outright bites you, you may be hurting him. If you suspect your cat is in pain, take her to the vet.

This is Harrie, cute, right? Well, she is a true little femme fatale … and an infallible exterminator of cockroaches.