Why do cats purr?
The Purr Engine
Why do cats purr?
Your cat is curled up on your lap, eyes half-closed, and suddenly you hear it — a gentle rumbling, like a tiny motor running in her chest. What's making that sound, and why does she do it?
The purr comes from muscles in your cat's throat. About 25 times per second, these muscles squeeze and release around the voice box, making the air vibrate as your cat breathes in and out. It's the same basic idea as humming — except cats can do it continuously, even while breathing, which humans can't pull off.
