why does my cat wag its tail

You reach out to stroke the cat and its tail begins to swish, slow and heavy against the floor. In a dog, a wagging tail means delight. If you assume the same of a cat, you are about to get bitten. A cat's tail is one of the most honest signals it has, but it speaks a completely different language. Here is how to read it before it reads you the riot act.

The single most important thing to understand is this: in cats, a wagging or swishing tail usually means the opposite of what it means in dogs. Where a dog wags in happiness, a cat moves its tail most when it is aroused, irritated, agitated, or intensely focused. A relaxed, contented cat generally holds its tail fairly still. So when that tail starts thrashing, it is rarely an invitation. It is more often a warning, and cats give it precisely because they would prefer not to escalate to teeth.

reading the tail

The exact message is in the speed and style of the movement, and in the rest of the cat. A big, fast, thrashing tail whipping side to side is a clear sign of an annoyed or overstimulated cat, and it is the one to respect most, because a cat swishing like that during a stroke is telling you it has had enough and the next step is a bite. This is the tail behind a great deal of what people call sudden, unprovoked biting, which is neither sudden nor unprovoked once you have learned to watch the tail. It ties directly into the overstimulation described in why does my cat bite me.

A slower movement, or just the very tip of the tail twitching while the rest stays still, signals a milder version of the same thing: mild irritation, concentration, or a cat weighing something up. You will often see the tip flick while a cat watches a bird or a toy, its focus narrowing before a pounce. It is not anger exactly, but it is not an invitation to interrupt either.

Not every tail movement is a complaint, though, which is where people get caught out. A tail held straight up with a little quiver or vibration at the tip, usually as a cat approaches you, is a genuinely happy greeting, an excited hello reserved for humans and cats it likes. And a tail puffed up into a bottle brush, held stiff or arched, is fear or defensive aggression, a cat trying to look bigger because something has alarmed it. The lesson is always the same: do not read the tail in isolation. Read it together with the ears, the eyes, the body, and the situation, and it will tell you almost everything about the cat's mood.

what to do about a swishing tail

Mostly, believe it. If you are stroking a cat and its tail begins to thrash, stop, and give the cat space rather than pushing on and getting bitten for your trouble. If a cat approaches with its tail up and quivering, that is your green light for affection. And if the tail puffs up and the cat looks alarmed, something has frightened it, so remove the trigger if you can and let it calm down rather than crowding it.

One note worth adding: because the tail carries so much information and does so much moving, it is also worth knowing that the tail can be injured, and a cat holding its tail limply, unable to move it, or reacting with pain when it is touched, is a cat with a possible injury that needs a vet, not a mood to interpret. But the everyday swishing tail is not an injury and not a mystery. It is a cat telling you, plainly and in advance, exactly how it feels. Learn to read it and you will get bitten a great deal less, which the cat would also prefer, as biting is beneath us and we only resort to it when ignored.

Related reading from my desk: why does my cat bite me, where the thrashing tail often leads, and why does my cat chatter at birds, on the focused, tip-twitching hunter.

A tail held limp, immobile, or painful to the touch can mean an injury and needs a vet. I am a cat with opinions, not a veterinarian.