Why Do Cats Purr?

By April 6, 2021 April 7th, 2021 Our Doctors

Cats make one of the most satisfying sounds in the world: they purr. [...] Almost all cats make us feel good about ourselves because they let us know they feel good about us... A purring cat is a form of high praise... It is a reinforcement of something we would all like to believe about ourselves -- that we are nice.

Roger A. Caras, A Celebration Of Cats

We all know that cats purr when they feel content, but did you know that purring is also a way cats comfort themselves? A cat that is scared may purr to comfort itself instead of hissing or scratching. The adorable kneading behavior that can occur along with it is actually a reflex carried over from kittenhood. Interestingly, science has shown us that purring not only soothes the cat, it has a positive influence on our healing as well.

So what causes this sound to be emitted from our feline friends? The short answer is that no one really knows. The cat’s conscious thought process controls its body’s physical purr-response so when the cat is sedated for doctors to try to visualize what happens in the body through MRI or CT, the cat can’t produce the sound. However, there are several theories as to what happens physiologically when cats choose to purr. The common school of thought is that the cat can vibrate its vocal cords to produce the sound. Another idea is that the cat can control its diaphragm and laryngeal movement to produce the rumbling sound. This theory is gaining credibility as the cat can still breathe while purring, their vocal sounds just change when they do.

Most cats can purr, whether big or small, and they typically purr at a frequency that will promote tissue regeneration, ~26 Hertz. Doctors believe cats will purr while waiting on a hunt to prevent muscle atrophy and promote bone health. In the human medical field, machines have been designed to produce these same tissue regenerating results.

Why do cats purr? It’s an instinctual response to a few different situations. They may feel content in their environment, they may feel stress and need contentment, or they may also have an injury or illness. If you find your cat is purring but they aren’t acting like themselves, we recommend that you call your primary care veterinarian and schedule a check-up. This could be a signal that your cat isn’t feeling well and needs medical attention. Some cats purr at the vet when they are nervous and trying to comfort themselves. And some cats purr when they finally find the perfect human lap and get settled in for a good rest. It all depends on the environment your cat is in when they purr and how they behave. Ultimately, if you have concerns about your feline companion, please contact your veterinarian to get them in for a physical examination.

– Dr. Brianna Mundahl

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