Why do cats purr?

Indeed, why do cats purr? Cat lovers, non-cat lovers, animal lovers in general, and scientists have asked this question. A related question is how do cats purr? Most experts do agree that purring is a form of communication.

Interestingly enough, the ability to purr (or at least the ability to emit a similar sound) occurs in all felines, including the big cats.

This article will explore the mechanics of and the reasons behind purring.

So why do cats purr?

Happy purring

I love the sound of a cat purring. I find it soothing and relaxing. And it’s very intriguing too. I have asked myself many times what it all means.

Many people think that cats only purr when they are happy, content and/or relaxed. And this assumption is valid, as far as experts know. Indeed, cats purr when they are touched and petted by their human companions. Some cats also purr while they are eating. My cats purr when they groom each other, too.

However, according to the experts, cats not only purr when they feel good, but they also purr to communicate with their young and with their human companions. If they are petted, for example, felines might purr to express their satisfaction and pleasure.

Female cats are known to purr when they nurse their kittens. Cats also purr when they are under stress and even when they are in pain. One of my cats would purr very loudly after she came out of a major surgery.

So again, why do cats purr? Seems like felines use purring to express different types of emotions as well as a means of communication.

Purring and healing

Some experts believe that purring has healing properties. According to a Scientific American article, cats purr at a frequency between 25 and 150 Hertz.

In fact, studies have shown that the cat’s purr can help improve bone density. So maybe cats purr to help accelerate healing, especially if they have suffered a bone injury.

Here's the Scientific American article.

How do cats purr?

So how do cats produce that internal vibration we find so interesting? Does it come from the throat or from the chest? In fact, there is no definitive answer to how cats produce their purr. This is due in part to the lack of a specific organ that generates this sound.

One theory (based on studies) shows that cats make this vibration by a rapid twitching of the muscles in the larynx. Such action opens and closes the glottis which causes vibrations during the inhalation and exhalation process.

Felines of the Panthera genus, which includes the tiger, the lion, and the leopard, only purr during exhalation.