A cat that rolls over, gets stroked, and then bites is not being unpredictable. It is one of several separate things, and which one it is decides what to do about it.
Cornell's feline health center describes it directly.
some cats may suddenly become aggressive when being petted... Possible explanations include overstimulation and an attempt by the cat to control when the petting ends.
It has a name in the veterinary literature and it is common enough that behaviorists see it constantly. The cat solicits attention, enjoys it, and then reaches a point where the same stroking stops feeling good. The bite is the full stop, not an ambush.
It is also usually signposted. The signs to watch for are a body that goes stiff, a tail that starts twitching or thumping, ears turning back or rotating, and pupils getting wider. All of those come before the teeth. Once you know them you can stop while it is still going well.
Researchers stroked cats on different parts of the body and scored their reactions. The area that produced the most negative responses was the back end, around the base of the tail. The cat friendly interaction guidelines say the same from clinical experience: cats mostly like being touched around the head and neck, where their own scent glands are, and mostly dislike being touched along the back end, the belly and the feet.
The exposed belly is the classic trap. A cat rolling over is showing you it is relaxed. It is not a request.
The same guidelines add something worth knowing: interactions last longer when the cat comes to the person rather than the person going to the cat, and letting a cat move during handling produces better outcomes than holding it still.
Cats learn that they are biting or scratching too hard when their littermates stop playing or retaliate. Cats raised alone during their early lives may not learn this important lesson.
That is Cornell again, and it explains a lot of single kittens. The fix is not punishment, which teaches a cat that hands are dangerous. It is giving the biting somewhere else to go: a toy on a string that keeps your hands out of the game, and play often enough that the cat is not inventing its own.
Redirected aggression is when a cat is wound up by something it cannot reach, and the nearest living thing gets it instead. Cornell lists the usual triggers as loud noises, seeing a strange cat through a window, or a fight with another cat in the house.
The part owners are never told is the timing. A review of owner-directed aggression written by veterinary behaviorists at North Carolina State notes that a cat can stay in a highly aroused state for hours, and sometimes days, after the trigger. So the cat that attacked you in the hallway may have seen something through the window that morning. Separating the cat and leaving it alone to come down is the right move, and it takes longer than feels reasonable.
Cornell is clear that this is not only a behavior question.
Diseases such as hyperthyroidism, osteoarthritis, dental disease, and central nervous system problems may cause aggression.
Arthritis in particular shows up exactly as this complaint. AAHA's guide to joint disease lists resistance to being handled, picked up, petted, or stroked along the back and limbs as behavior changes caused by osteoarthritis, and notes that estimates of joint disease in cats run very high. A cat that used to enjoy being stroked along the spine and now objects may not have changed its mind. It may hurt.
The behavior management guidelines put the order plainly: treat any underlying medical condition before starting behavioral treatment. So a cat that has recently started biting gets a vet appointment first, not a training plan.
Researchers at the University of Montreal built the Feline Grimace Scale, which scores five things in a cat's face: the ears, the tightening around the eyes, the tension in the muzzle, the whiskers and the position of the head. It was validated against another established pain measure in 2019. A second study in 2021 tested it on cat owners rather than vets, and found owners scored cats consistently enough to be useful. It is for sudden pain rather than long-term arthritis, and it does not replace a vet, but it is something you can do at home tonight.
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