There is probably nothing cozier or more soothing than having a purring cat vibrating on your lap, with an increasing and more intense brrrrr-sound when you find just the right spot under the chin. But why do they actually purr, and what does it mean?
How does the sound occur?
The purring sound itself arises from muscles in the cat's larynx. The muscles contract and relax at a rapid rate, therefore creating a vibration. When air passes through the larynx as the cat breathes, the cozy humming sound is created.
Why do cats purr - does it serve a function?
Cats don't just purr when they're petted by their favorite human - it's also used as communication between cats. Cats purr when they groom each other and kittens can help their mother find them by purring. Even the mother cat purrs to make her kittens feel safe and calm, and the kittens can purr when nursing.
In other words, the function behind purring is a form of communication. It's a sound that means: I like you, and this is cozy! Communication strengthens the relationship between cats, and between cats and people, and purring is the cat's way of signaling that it is happy, comfortable and friendly.
Does purring always mean the cat is happy?
Cats can purr in other contexts than when they are lying in their favorite chair and being petted by their owner. Have you heard your cat purr through the entire vet visit? It is then usually due to stress, as the purring has a calming effect on the cat itself. Although, there are exceptions with individual cats who think a vet visit is the coziest thing in the whole world....
The cat can also purr when it is in pain or sick. Here, too, it is suspected that the purring has a calming effect, but there are also theories that it can have a pain-relieving and even healing effect.
You generally do not need to worry that your cat is in pain when it purrs, if it otherwise seems healthy and well, and purrs in completely expected situations: when it is basking in the sun, cuddling with you, or head-bumping your legs when waiting for food. If, on the other hand, it seems uncomfortable, tense or hide away and purr without wanting to be touched - then purring can be a signal that the cat is not feeling well.
Why do cats purr
The bonus-effect on the pawrent
Having a purring cat on your lap is not only cozy for the cat - it also has positive effects on us humans. Having animals around us makes us calm and less stressed, and petting and cuddling with your cat on your lap releases feel-good hormones in us humans.
So, keep cuddling and snuggling, it really only has benefits: happy cat, stronger relationship and well-being of pawrents.