If you have a cat, it's likely that at some point you've seen it do this: while playing with your foot it suddenly dropped to its side, latched on with its front claws and began a coordinated kicking motion with both back legs.  

 

The cat probably gave you a good four or five swats before letting go. From a human point of view this looks like great fun--a real rough-and-tumble kind of game. But where does it come from?

 

Before giving an answer, let's think for a second about the kind of thing we can learn even from so commonplace an event. Housepets are not toys; although they are domesticated and, in the instance of cats, much smaller than their wild counterparts, it's a mistake to regard them as fundamentally different from wild animals. They share millions of years of evolutionary history, and their behaviors--even playful ones--are in many cases behavior that was very useful in the wild.

 

So, think again about that front-claw grab connected with a back-claw kick that your cat does from time to time. You may see it in a new light when you realize that the cat is executing a very effective device for killing prey or enemies: hold the other animal's stomach in place while you disembowel it.

 

Of course, that doesn't mean your cat is really trying to hurt you; but it does show us that playful behavior in animals --and, oftentimes, in humans--is not simply nonsense. In many cases it is a practice run for learning more useful skills--even deadly ones.