Cats are the only animals that purr. What does this sound mean and why do they do it? Contrary to popular belief, purring isn’t speaking.  The purr comes from two membrane folds that are called false vocal cords. These are situated in the larynx behind the  actual vocal cords. Cats purr 26 cycles per second. Cats can purr whether they are inhaling or exhaling and they purr keeping their mouth completely closed.  Some scientists believe that purring is produced by blood in a large vein in the chest cavity that vibrates by air in the windpipe.  Kittens are born blind and deaf but the purring by the mother is a physical signal that the kittens can feel. This is comforting to them.  It also acts as a homing device, signaling them to nurse.  Kittens begin purring by about one week old.  This is a signal to their mother that they are getting milk and are content.

Contrary to popular belief, cats don’t purr purely for pleasure.  A deep purr can indicate that a cat is in pain or distress. Female cats will purr when they are in labor.  Cats may also purr in fear or anxiety. They will also purr in anticipation of being fed or being stroked.  Another interesting fact, according to scientists, cars will never purr if they are alone.  You will hear them purring while they are lying nice and cozy in their cat bed.