Why do Cats Purr?

Similar to Roaring, No Cat can do Both

Do questions like this keep you awake at night or, like most cat owners, do you believe your kitty purrs just because he thinks you’re cute, funny, smart, and marvelous? Sorry. As it turns out, it’s purely physical.


The mechanics of purring start with a neural oscillator in the brain that transmits signals to the muscles of the voice box causing them to vibrate at 25 cycles per second. It’s a trait that domestic cats, pumas, cheetahs, ocelots, bobcats, lynx, and African wild cats share. Cats who roar, on the other hand, include lions, jaguars, and leopards. Due to anatomic differences in the hyoid bones of the voice box there is no way for purrers to roar nor for roarers to purr. If you’re a cat you just can’t have it both ways.


Purrers purr in the best of times and the worst of times. Those vibrations promote healing of stressed or injured muscles following a strenuous hunt. Purring also tones the muscles of couch potato cats who, unlike their sedentary owners, lose none of their physical condition lying motionless in front of the TV. Lazy cats may be porkers but their muscles are like coiled springs.


Purring is remarkable for feline healing and wellness. A mother cat purrs to recover from birthing; her kittens do it to grow stronger bones. In veterinary practice we sometimes hear seriously sick or injured cats purr. They are stressed and miserable but as we work to save them they instinctively do their best to help.