Kevin Drisko, age 10, of South Portland, Me., for his question:

WHAT IS A RATTLER'S RATTLE?

The rattlesnake's hissing rattle is a string of bony little beads on the end of his tail. When he gets upset, he shakes the tip of his tail and these horny segments rattle together. There is a bump on the end of each segment that fits into a dent on the next one. A baby rattler has one little segment, and one or more larger ones are added each time he sheds his skin.

Some people say that the number of segments in the rattler's tail reveals his age. But this is not very reliable. He may add as many as four new rattle segments when he sheds his skin  and he may shed more than once during a year.

What's more, if the rattler is an old timer, the smaller beads on the end of his rattle tend to fall off. Usually he keeps no more than 10 segments at the end of his tail.