Bravo Lars! Your exactly right. It's called a cuica (pronounced kwee-ka). You'll hear it primarily in brazilian music. It is indeed a drum with a thin peice of bamboo fastened to the inside of the drum head. It's a friction drum as opposed to a precussion drum. It's played by rubbing the stick with a wet cloth (now that sounds perverted). Different tones are created by a combination of depressing the head with your finger tips, and how tightly you rub you stick (not the monkeys' stick).
Roughly translated cuica mean "lion drum". It was used to hunt lions by emulating the mewling sound of a lioness, and brought to brazil by africans.
