Why do Cats Purr?

June 26, 2015 / Animal Factoids / 0 Comments /
Picture of a happy cat purring

I’ve had cats all my life, and always wondered why they purr. I have always assumed it was to do with their happiness, and the louder they purred the happier they were, although I have noticed that when cats are at their happiest, they are not necessarily purring. To quench my years of wondering why cats purr, I decided to research it, and so here, I’ll explain what I have found.


Purr for happiness

We know that cats learn to purr at a very young age, and it is possibly a bonding mechanism kittens use to communicate with their mothers. It has been suggested that it lets the mother know that they are ok, and nothing is wrong. The purring carries on into their adult life perhaps out of habit, or to communicate to their owners that they are ok (after all, pet owners and their pets have a similar relationship to mother and young child). but this is just speculation.

Still, there is little doubt that cats will often purr to show that they are happy and content. The loudest purr I’ve heard come from a cat is when it is eating its favorite food – which suggests it displays some enjoyment. This is no surprise.


Purr for healing

I saw a very sick cat purring once when I was young, and was very confused until I did some reading on it. It appears that cats are exceptional healers, and that this is thought to be a result of their purr. Cats have a much lower post-operative complications than dogs do, and have a very low incidence of bone disease.

How can purring heal?? Well, there is some evidence that purring can help healing, particularly with regards to bone health. A domestic cat will purr between 20Hz and 30Hz (in fact, any cats such as cheetahs which purr, purr in this frequency range). Research published in 2001 showed that exposing bones to vibrations of this frequency for 20mins a day increased bone strength.

In addition to this, vibrational therapy has been used in sports medicine for a number of years to help strengthen tendons, muscles and improve recovery; so it certainly isn’t unreasonable to think that a cats purr is a natural stimulation for bone health and muscle conditioning.

Considering cats will be constantly climbing and jumping large distances for an animal of their size, they will need very strong muscles and bones to avoid damage, so a purr may be something they evolved to do to condition/ strengthen their bones.

Either way, the healing and strengthening properties of the cats purr cannot be ignored, and is a very unique evolutionary adaptation to an agile lifestyle.

Purr for communication

You may not realise it, but cats do have different purrs which they use to communicate with humans. Research conducted in the  University of Sussex has shown that cats will produce a different purr around feeding time to encourage humans to give them food. In fact, people who don’t own cats were able to detect a bit of urgency to this particular type of purr, and they wouldn’t have heard it at feeding time before.


Summary – why cats purr

Although there is some uncertainty for the exact reason for the purr, there is some interesting research into it.

As many people know, the cats purr signals happiness and content. It is understandable that they purr for communication both to their owners and other cats, but the most interesting aspect of the purr is its healing properties. No other animal has developed this special method for conditioning their muscles and bones, and it is possibly the most fascinating aspect of the cats purr!

Images courtesy of Trish Hamme and Akimasa Harada

This Youtube video will give an overview of the information found on the article tab. If you want to know more about the topic, or want to see where the information came from, have a read of the article after you watch the video.

Cats purr to communicate (mainly to show content/ happiness, but also for food and possibly other reasons). The vibrations also help to strengthen bones and muscles.