Cats also purr when they are injured or sometimes when they are scared. This is believed to be a form of self-soothing. I've actually been able to replicate my

Cats also purr when they are injured or sometimes when they are scared. This is believed to be a form of self-soothing. I've actually been able to replicate my own form of purring at roughly the right frequency, but it takes a lot of air moving across the vocal cords to do that, and you end up hyperventilating. But, it does produce slightly different sounds on the intake versus the exhalation, as you hear with real cat purring. I can't do it for long, but I can do it.