Why do cats purr?

These comforting sounds are good for them and for us, too.
It’s easy to assume that cats purr because they’re happy. After all, when your kitty contentedly curls up in your lap for some well-deserved scratches and rubs, she’s obviously one happy feline.
However, cats also purr when they’re frightened or feel threatened, such as during a visit to the vet.

Veterinarian Kelly Morgan equates this reaction with smiling. “People will smile when they’re nervous, when they want something, and when they’re happy, so perhaps the purr can also be an appeasing gesture,” Morgan told

A cat’s purr begins in its brain. A repetitive neural oscillator sends messages to the laryngeal muscles, causing them to twitch at a rate of 25 to 150 vibrations per second. This causes the vocal cords to separate when the cat inhales and exhales, producing a purr.

But not all cats can purr. Domestic cats, some wild cats and their relatives — civets, genets and mongooses — purr, and even hyenas, raccoons and guinea pigs can purr. However, cats that purr can’t roar, and cats that roar can’t purr because the structures surrounding roaring cats’ larynxes aren’t stiff enough to allow purring.

However, your cat may also purr to communicate with you. According to researchers at the University of Sussex, domestic cats can hide a plaintive cry within their purrs that irritates their humans while appealing to their nurturing instincts.
Purring isn’t just good for cats though — it’s also healthy for cat owners. Studies show that cats do a better job of relieving stress and lowering blood pressure than other pets. In fact, a 10-year study at the University of Minnesota Stroke Center found that cat owners were 40 percent less likely to have heart attacks than non-cat owners — and purring might play a role in that.