Why do cats purr?
12 September, 2011


There is nothing more soothing or interesting (at least to a cat owner) than the sound of a cat purring.  It is almost melodic.  When my cat purrs, it makes me happy because it means that he is happy.   And, not all cats purr for the same reason.

You would think it would be easy to explain how a cat makes such a cool sound, but no one really knows how cats purr.



Purring is a form of feline communication. It is a sound produced with the mouth closed. Purring is used as both a greeting and as a care-soliciting signal. Purring signals friendly social interactions between cats and is used when cats approach each other, are resting together, groom one another, rub against each other, or touch noses. Kittens start purring when first nursing, and the mother purrs back to the kitten, both reassuring one another that “all is well.” Both are satisfied and content. Kittens can purr and nurse simultaneously, but cannot meow and nurse at the same time.

Believe it or not, purring also occurs in sick, injured, frightened—and even dying cats. Experts believe this is the “care-soliciting” form of the purr, communicating to others that the cat feels bad and that he is not a threat. If your cat looks or acts sick, but is purring, you should take him to your veterinarian for a complete check-up.

Cat owners love to greet and be greeted by their cats. Cats greet us with purrs and trills when we approach them, or pet, stroke and feed them. There is evidence that petting your cat lowers your stress level and improves your immune system. The positive social interaction between owners and their cats is mutually beneficial for both of them, reassuring each other that “all is well.”


Many veterinarians have various theories to explain what might produce the purr, although none have yet been proven. One theory is that purring is the result of electrical impulses generated in the brain that are transmitted through the central nervous system to muscles near the larynx (voice box) and diaphragm. The nerve impulses cause rhythmic contractions of these muscles during both inhalation and exhalation, while the cat’s mouth is closed. Vibrations are felt throughout the cat’s body, but are audible from the nose and mouth.

Veterinarians have found that sound frequencies in this range may improve bone density and increase the efficiency of the circulatory system. This may promote healing while the cat expends minimal energy. Studies have also found that the cat’s brain releases endorphins (happy hormones) while purring.

All in all, a purring cat is a happy cat!

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