How (And Why) Do Cats Purr?

Cats purr for all kinds of reasons, including communication and healing themselves. Cristen explains how purring works and which cats can't do it. Whether the topic is popcorn or particle physics, you can count on the HowStuffWorks team to explore - and explain - the everyday science in the world around us on BrainStuff. Download the New TestTube iOS app! http://testu.be/1ndmmMq Watch More BrainStuff on TestTube http://testtube.com/brainstuff Subscribe Now! http://www.youtube.com/subscription_center?ad… Watch More http://www.youtube.com/BrainStuffShow Twitter http://twitter.com/BrainStuffHSW Facebook http://facebook.com/BrainStuff Google+ http://gplus.to/BrainStuff