Jan McVey, age ll, of San Bernardino, Calif., for her question:

Does a turtle have teeth?

You would expect the alligator turtle to have toothy jaws. Certainly the saw toothed turtle: should have teeth, and surely the gopher turtle needs teeth to devour his victim, the gopher. But the turtles and their land dwelling tortoise cousins are reptiles of many surprising features.

Most turtles pull in their heads and legs when trouble threatens, but the scrappy snapper turtle is always eager to attack. As everyone knows, he attacks his foes and those he thinks are his foe by biting. He grabs and holds a piece of his enemy in his mighty jaws. If you have been bitten by one of these scrappy snappers, you feel surf that his jaws are lined with teeth.

If you have been bitten by his whopping cousin, the alligator snapper, it will be everi harder to convince you that turtles have no teeth. Neither the water loving turtles nor their land dwelling tortoise cousins have one single tooth among them. Yet some of them devour meat and tear off bite sized morsels of their struggling victims. And the snapper seems to try and almost to succeed at grabbing a bite of human flesh.

The turtle's mouth actually is a bill or beak, and the jaws are made of hard, horny material. The bill is strong enough to shred the toughest plant food or tear off bites from meaty victims. Many turtles dine an fish and some of them tackle shellfish. As a rule, bugs and grubs, worms and waterweeds are also on the menu. A few turtles eat only waterureede and other greenery of the plant world.

Turtles and tortoises are reptiles and so are related to snakes, lizards and toothy crocodiles. Their ancestors were on earth long before the mighty dinosaur lizards, and the turtles of today are not very different from the turtles of l50 million years ago. Bec8use of this long story of successful life on earth, they have been called living fossils of the ancient past.

Perhaps the secret of this success is in the turtle's shell. Only a few turtles are bold enough to attack, and most of them prefer to hide from their enemies. In nature, combat is always risky, so the turtle often avoids these risks by retiring inside his well armored shell.

The shell of a turtle protects his back and underside. There are slots for his tail, his long neck and four limbs which may be flippers or clawed feet. The body inside the shell has a skelton with a backbone and jointed bones. The tortoise has stubby feet for walking on land. The giant galapagos turtle who outlives all other animals is actually a tortoise.