Kathy McConnell, age 10, of Lethbridge, Alberta, Canada, for her question:

Do the rattles tell the age of a rattlesnake?

Nature is beauteous and generous, but she always includes a few bewares to test how smart we are. Right now, the summer sun beckons us to explore outdoors and let's not miss a thing. But let's also brush up on those bewares. Rattlers are deadly snakes. Sensible folk arm them¬selves with knowledge, including which rattlers are found where, how to avoid them and what to do just in case of a bite.

Every summer we are warned and warned to beware of rattlesnakes. And no doubt many sensible persons pay attention. On the other hand, every summer many get bitten by poisonous rattler fangs. With proper medical attention, almost all victims survive. But every year, rattle¬snake poison proves fatal to a small proportion of those struck, and makes others very sick. Let's think about that for a moment.

Certainly no sensible person wishes to examine and count the rattlers on a snake in person, even though the snake looks deader than a doornail. Obviously this is a case when we should depend on information from experts, who know how to examine rattlers without risk.

The rattle itself is a string of horny beads attached to the far end of the snake's tail. When he shakes it, it vibrates with a sort of fizzy crackle. Many people believe that the rattler always rattles a warning before he strikes. This tale is not to be trusted because they can and sometimes do strike without warning. In any case, if you hear that wretched rattle, run    do not walk    in the opposite direction.

It is true that a junior rattlesnake adds more bony beads to his rattle as he grows older. For this reason, we would expect a grand proves to be true, but not always.

The little bony beads are locked together, but things can happen to shake them loose. For example, a snake may lose one or more rattles from the far end of his tail    and this can happen at any time of life. In such cases, the number of rattles cannot tell his true age.

There is another reason why the rattles may misrepresent his age. An extra bead is added to the string each time the snake sheds his skin. Many people take it for granted that he sheds his shabby old skin for a new one just once every year. This, no doubt, is how people got the idea that counting the rattles would tell his age.

However, skin shedding is an agonizing business and no snake does it more often than he has to. Youngsters and teenagers usually have to shed two or three times during their time of early growth    which adds more than one rattle a year. Adults must shed when the shabby old skin becomes too scuffed for comfort. With average wear and tear, this may be once a year    which adds one new rattle a year.

If a rattler sheds once a year and loses none of his little beads, then his rattle will tell the truth about his age. However, this neat record usually varies somewhat. He may add extra rattles by shedding more than once during a year. Or one or more of the bony beads may be lost in some sort of accident.