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Why Do Cats Purr? It's Not Always Happiness
- Purring is most often a sign of comfort and trust, but cats can also purr when they are stressed, sick or in pain.
- Kittens start purring within days of birth while nursing, and mother cats purr back — it is an early 'all is well' signal.
- The sound alone is not enough: read it together with body language and the situation.
Where does the purr come from?
A purr is produced by rapid twitching of the muscles of the larynx (voice box) as the cat breathes in and out, which makes the vocal folds vibrate. That is why a cat can purr continuously, on both the in-breath and the out-breath.
The most familiar purr is the relaxed one: on your lap, while being stroked, or when settling down to sleep. In these moments the purr is a sign that your cat feels safe with you.
Purring that does not mean 'happy'
Cats also purr in situations that are clearly not pleasant — at the vet, while recovering from an injury, during labour, or when they are seriously ill. Many behaviourists think purring can work as a self-soothing behaviour, a little like a person humming to stay calm.
So a purring cat is not automatically a comfortable cat. If your cat purrs while hiding, refusing food or holding a tense body posture, take it seriously.
The 'solicitation purr'
Some cats use a special purr when they want food: a purr mixed with a higher-pitched, cry-like sound. A 2009 study from the University of Sussex found that people rated this kind of purr as more urgent and less pleasant, which may be exactly why it works so well at breakfast time.
How to read your cat's purr
Look at the whole cat. A relaxed purr usually comes with half-closed eyes or slow blinks, ears facing forward, whiskers relaxed and a loose, soft body.
A stressed purr may come with ears turned back or flattened, wide pupils, a crouched or tense body and a tail held tight or flicking. The same sound can mean different things depending on what the rest of the body is saying.
Every cat is different. Learning what is normal for your own cat — how often, how loud, in which situations — is the best way to notice when something changes.
- When your cat purrs, note the position of the ears, eyes, whiskers and tail.
- Keep a short log of when purring happens (being stroked, alone, new places) to see your cat's pattern.
- Let your cat decide how much touch it wants — stop if the ears go back or the tail starts to lash.
Frequently asked questions
My cat purrs and shows its belly. Can I rub it?
A belly-up cat is showing trust, but many cats do not like belly rubs. Offer a hand nearby first and watch the reaction; if the ears turn back or the tail tenses, stop.
My cat purrs a lot at night. Is it sick?
Purring at night is usually normal. But if it is new, much more frequent than usual, or comes with changes in appetite or litter-box habits, ask your vet.
My newly adopted cat never purrs. Is it anxious?
Some cats need days or weeks to settle in, and some simply purr very quietly. Give a safe hiding place, keep routines calm and let the cat come to you.