Why do cats expose their soft belly and then attack you for petting them? Well, firstly you can’t presume that when a cat presents her belly to you that she wants it petted.
Presenting the belly is a sign that your cat is relaxed and confident in your presence. It is not necessarily an invitation to pet it but more an invitation to play. I realise that it is a very tempting sight; the gorgeous, warm, furry and soft belly of a domestic cat.
The temptation is hard to resist and we see the body language as a request to rub the belly. Perhaps we use human body language to interpret feline body language which may mislead us.
When you do pet her belly it can tend to trigger what I’d call ‘the play response’ as the cat regards your petting of his belly as playing. The play response from the cat includes biting and grabbing because for cats play means fighting. It’s a substitute for hunting.
This results in your hand being grabbed by your cat’s paws with claws sometimes out so it hurts a bit followed by a friendly nibble which for the cat is relatively gentle and playful but for you it’s not: it hurts.
Then when you try and free yourself your cat grabs harder and that hurts too because she wants to keep playing and pulling your hand away is part of the game – it’s prey escaping.
What to do?
The answer is to pet your cat’s belly very gently indeed and only if you’re convinced that she will not engage in play as a response. A lot of domestic cats, no matter how friendly and bonded with their owner might not react in a way that you consider desirable. After time your cat might learn that you don’t want the play response.
The response that you want is for your cat to demonstrate to you that she likes being petted on the belly; to purr and feel content. What you don’t really want is to play with your cat using your hand! That can lead to scratches.