Robert Bowman, age 16, of Chicago, Ill., for his question:

How do snakes obtain their lethal poison?

Snakes are supposed to hibernate and stay safely out of the way during the cold months. But in Florida where the winters may be mild, the poisonous cottonmouth stays active through most of the year. In the southwestern deserts, deadly rattlers may be out in December.

All of the 3,000 different snakes in the world are meat eaters. Their groceries include fish and frogs, eggs, birds and assorted reptiles. But the majority of snake food is supplied by rats and other rodents. These furry mammals are quicker and smarter than the snakes that are not very well equipped to catch them. They have no padded paws for stealthy prowling and no legs for pouncing on their prey.

Every snake, however, has some other means for catching and subduing his victims. His supple body enables him to creep up silently and almost invisibly. His rows of sharp teeth curve backward to help him grab and grip his prey while he swallows it alive, head first in one gulp. Grass snakes, king snakes and many others harmless to man make a living with no more than this built in equipment.

The large boas and pythons make use of their powerful coils to suffocate their victims. A few members of the snake world are equipped with fangs to inject deadly venom meant to paralyze their struggling victims. All snakes have special stretchable jaws that enable them to swallow animals as large or larger than themselves. A poisonous snake strikes out at people and large animals that come close enough. Some of these animals soon become helpless enough for the snake to catch and swallow.

A poisonous snake has two extra long, curved teeth in his upper jaw. Each of these fangs is hollow with a hole at the tip through which venom is injected into the victim. Another small hole at the top of the fang is placed to catch venom oozing from a duct in the jaw. The poison is manufactured by a gland in the snake’s head, but exactly how this specialized job is done, we are not certain. The snake has a poison making gland in the bony skull behind each eye. As drops of the venom are made, they drip down a tube that ends in the duct above each fang. Then he strikes several times in a hurry; the snake may use up all his venom. He can poison no more victims until more supplies are made.

All snakes shed a few teeth from time to time. Once in a while the poisonous snake must shed his fangs, but he is never left without the means to strike. Then a fang becomes old, a new one grows in to replace it, and for a while the snake may have two fangs in one side of his jaw. The new fang takes over when the old one falls out or remains stuck in the flesh of a victim. Sometime later, the fang on the other side of the jaw will be replaced in the same manner by a new one.