Start with the tail
The tail carries more information than any other part of a cat, and it is the fastest thing to learn. A dog's wagging tail means engagement; a cat's swishing tail means the opposite, and mixing the two up is behind a great many bites.
- Straight up, tip relaxed
- The friendly greeting. A cat approaching you tail-up is choosing to interact. A slight question-mark hook at the tip is the warmest version of it.
- Low or tucked
- Uncertain or frightened. A cat moving through a room with its tail low is not comfortable in that room.
- Puffed and arched
- Startled and trying to look bigger. This is fear, not aggression, though it can become defensive aggression if cornered.
- Swishing or thumping
- Agitation, building. A cat thumping its tail on the sofa while you stroke it is telling you to stop. This is the single most-ignored signal in cat ownership.
- Fast tip-twitch only
- Focus — usually hunting or watching something out of the window. Not a warning on its own.
- Wrapped around you or another cat
- Affiliative. Cats do this with individuals they consider part of their group.
Ears and eyes
Ears rotate independently and move faster than anything else on a cat. Forward and upright is interested and relaxed. Swivelled sideways — the shape people call airplane ears — is agitation or fear. Flattened hard against the skull is a cat that is about to defend itself, and it is the last stop before contact.
Pupils are about arousal rather than mood, and light confounds them, so read them alongside everything else. Wide, round pupils in ordinary light mean high arousal, which could be fear, excitement, or play. Narrowed to slits in a tense cat is often offensive rather than defensive.
The belly is not an invitation
A cat rolling over and showing its stomach is displaying trust — that much of the folklore is right. What people get wrong is the conclusion. In a dog, an exposed belly is often a request to rub it. In a cat, it is a statement that the cat feels safe enough to expose its most vulnerable area, and the usual response to a hand arriving there is all four sets of claws and the back feet.
There are cats that genuinely enjoy belly rubs, and if yours is one, carry on. But the default assumption should be that the roll is a compliment rather than a request.
Petting-induced aggression, explained
The classic complaint: the cat was purring on my lap and then bit me for no reason. There is always a reason, and there is almost always a warning, delivered somewhere between ten and thirty seconds before the bite.
The sequence runs: tail begins to twitch, then swish; skin along the back ripples; ears rotate sideways; the cat's head turns towards your hand; body stiffens. Then the bite. Every one of those is easy to miss if you are watching television, which is when this always happens.
The fix is simple: stop before the cat asks you to. Short sessions, ending while the cat still wants more. Stick to the head, cheeks and chin, which is where cats groom each other — the base of the tail and the length of the back are far more likely to tip a cat over.
Purring is not simply happiness
Cats purr when content, and they also purr when frightened, in pain, and while dying. It appears to be self-soothing as much as communication. A cat purring at the vet is usually not having a lovely time — a purr accompanied by flattened ears, a tucked tail, and a rigid body means something quite different from a purr on the sofa.
Meowing, meanwhile, is almost entirely a human-directed behavior. Adult cats rarely meow at each other; they developed it for us. A cat that suddenly becomes much more vocal is worth a vet visit — in older cats it is a common early sign of hyperthyroidism, high blood pressure, or cognitive decline.
Play versus fighting
In multi-cat households this is the question people most often get wrong, usually by assuming a scrap is play when it is not.
- Play
- Silent, or nearly. Claws in. Roles swap — first one on top, then the other. Pauses. Bodies loose. Nobody is trying to leave.
- Fighting
- Vocal — growling, yowling, shrieking. Claws out. One cat consistently on top and the other consistently trying to get away. Fur coming out. Ears apartment.
- The gray area
- One-sided play, where one cat is having fun and the other has stopped. Watch the one being chased: if it is hiding afterwards, avoiding rooms, or has stopped using a litter tray, this is bullying regardless of how it looks.
The signals that mean something is wrong
Cats conceal illness — a legacy of being both predator and prey — so behavior change is often the first and only symptom you get. Any of these is worth a vet call rather than a wait-and-see:
- Hiding more than usual, especially a cat that normally seeks company.
- A change in litter tray habits — see when a cat stops using the box.
- Stopping grooming, or overgrooming one patch until it is bald.
- Sitting hunched with the tail wrapped tight and eyes half closed — the classic cat-in-pain posture.
- Panting or open-mouth breathing. Never normal in a cat. This is same-day, not next-week.
- Sudden intolerance of being touched in a cat that was previously fine with it — very often pain rather than mood.
The general rule: with cats, the absence of a signal is itself a signal. A cat that has gone quiet, gone still, or gone under the bed and stayed there is telling you something, and it is usually worth listening to sooner than feels necessary.