Craig Dunman, age 11, of Visalia, Calif., for    his question:

HOW DOES A RATTLER RATTLE?

The sound of a rattler's rattle is a warning that he is all set to strike. And, as all of us know, his venomous bite is deadly dangerous. Nobody can say why he rattles his warning signal, but we do know how he does it.

The rattle attached to the end of his tail looks likea string of bony beads.Each bead is curved to fit around the one before it, and a new one is added each time the snake sheds his skin.

When he flicks his tail, as he usually does before striking, thebony beads joggle and rattle together. This is the time to stop asking questions and start running  in the opposite direction.