OK, here's a quiz for you. You have a tube that is fixed in space. You cannot move it. It is too small for you to get your hands into it, and there is a peanut in the bottom. You want the peanut. How do you extract the peanut?

Have a look at how this chimp did it:

http://www.youtube.com/watch?v=yrPb41hzYdw