Welcome to brain Stuff from how stuff works dot com. We're Smart Happens. I am Marshall Brain with today's question, how do cats pur? Humans seem to be fascinated by animals who can do things that we cannot. For example, how stuff Works covers questions about camel humps, hawk vision, dear night vision, fish gills, and so on, And so it is with cats purring. Humans can't pur, so we're
interested in how cats can do it. It turns out that domestic cats, some wild cats like pumas, and mountain lions in general, any big cat that can't roar, and even raccoons are all able to pur. Cats show happiness by purring. They may also purr when they're startled or upset. Humans happen to smile and laugh when we're happy, and dogs why their tails, So it's not unusual for an animal to have a physical reaction to happiness like this. So how do cats pur? It turns out that cats
have special wiring. The wiring travels from the brain to the muscles in their voice box, and this wiring is able to vibrate the muscles, so they act as a valve for air flowing past the voice box. The muscles work both during inhalation and exhalation, and that creates the impression that cats can pur continuously. The air passes through the valve, which opens and closes rapidly to create that purring sound. For more on this and thousands of other topics because it how stuff works. Dot com