How do cats purr?

[spider93]

What makes the sound of a cat purr/

[andy hughes]

A number of experiments have been conducted into the reasons how, and indeed why, cats purr, and the result is - no-one knows! There are two specific theories however, one is that the cat vibrates air in its larynx, and the other is that it vibrates large blood vesesls in its chest. The reaons are equally various - everyone knows cats purr when they are contented, but they also purr when they are giving birth, stressed, injured, or dying, so it's not entirely a pleasure indicator. Behaviourists believe the cat is sending out a 'non-threatening' message, to avoid aggression - nursing kittens purr at their mother, who purrs back. The actual mechanism that delivers the sound remains an intriguing mystery.

[ajkiddle]

The most common theory is that air is vibrated in the larynx, as the purr can be affected by rubbing the neck of the cat, the cat eating or the cat turning the purr into a meow to communicate to humans.