When you were a child, you were probably told that cats purr when they are happy. Therefore, we learned to associate the purr with pleasure, and we assumed that every time our feline friends were purring, it was because we were doing something to make them happy.

Some new information provided by respected veterinarians, Doctors Foster and Smith, provide some more nuanced information about purring cats. If you want to learn more about what REALLY gets your cat's motor running, read on!

Most pet owners interpret a purring, squinting cat as an obvious indication that their pet is both happy and healthy. They think that the purr always expresses contentment, showing that the cat is comfortable and feels secure.

This is not totally false, but it is also not the whole story.

Many cats do purr when they're happy. Recent research by pet behaviorists has suggested that purring originally developed as a communication mechanism between mothers and kittens. The kitten could purr to his mother, thereby signaling that "everything is alright." This occurs most frequently when kittens are nursing, because kittens can't meow and nurse simultaneously. Purring and nursing at the same time, however, can be done. When the mother hears the purr, she may reciprocate, thereby reassuring the kitten by this communication mechanism.

This explains why your cat may purr when you pet him: he instinctively gives the "everything is alright" message so that both of you know all is well.

But what are the other possibilities?

Sometimes, older cats use purring as a form of communicating when they approach other felines. This helps them show that they are not an enemy and that they want to come closer, maybe to play.

Perhaps most surprisingly, purring is also a way that cats communicate when they are scared or in distress. Have you noticed that cats in the veterinarian's office often purr? So do cats who are injured or otherwise ill. This might be a way that cats try to calm themselves down and reassure themselves.

Purring is only one way that cats communicate their moods, desires, and needs non-verbally. They may also use their eyes, squinting or blinking slowly. Other "typical" cat behavior, like stretching, facial rubbing, or spraying can also be forms of communication. If you really want to establish a connection with your cat, try purring back. You'll both know that you're listening!