Erik Harrison, age 12, of DeRalb, I11., for his question:
HOW DO LIZARDS REPRODUCE?
Lizards are reptiles and are closely related to snakes. Scientists have identified about 3,000 different kinds of lizards in many different parts of the world.
Most lizards lay eggs as part of their reproduction patterns. Some deposit them in simple nests. The female may then coil around the eggs and drive away any invaders. If the eggs become scattered, she brings them back together.
With some lizards, the female does not lay eggs but instead gives birth to living young after the eggs have hatched inside her body.
Still other lizards reproduce in somewhat the same way as mammals. These lizards also give birth to living young. But before birth, the developing lizard gets its food from the mother lizard's body, and not from an egg. Unlike female mammals, the female lizard does not nurse her young or care for them after birth.
Unlike snakes, some lizards eat plants instead of animals. Hundreds of other species eat mostly insects and small animals. Usually they do not limit their diets to any one thing.
Lizards do not have the built in body temperature control found in many other animals. Because of this, lizards live in places where the ground never freezes. Those that live in areas with cold winters must hibernate underground.
Lizards thrive in the tropics and in the warm parts of the temperate zones. They are the most common reptiles found in deserts and other dry regions. When the desert becomes too hot for comfort, lizards lie in the shade or under the sand to escape the rays of the sun.
Smallest lizard in the world is just an inch or so long. On the other end of the scale is the Komodo dragon, a huge East Indian lizard that can be about 10 feet long and weigh nearly 300 pounds.
Most lizards live on the ground or in trees.
One kind of lizard, called the gecko, has claws that it can draw in as a cat does. Its feet also have soft pads with tiny, brush like hooks. The claws catch on rough surfaces such as bark, and the pads cling to smoother ones. A gecko can walk upside down across a plaster ceiling without trouble, and can even cling to a pane of glass.
The Australian fringed lizard is one of several lizards that can run by raising the front of its body and running on its hind legs. It balances itself with its tail.
Many kinds of lizards called skinks have no legs. Other skinks have weak, nearly useless legs. And the glass snake of the Eastern United States is really a lizard without legs. It has well developed eyelids, unlike those of a snake.
Like the snake, a lizard usually can bluff or play tricks as a method of defense. The glass snake, for example, has a tail that is twice as long as its body. If an enemy seizes the lizard's tail, the animal pulls its body away from the tail and crawls to safety.
The tail keeps wriggling as though it were alive while the enemy struggles with it. The lizard doesn't seem to miss the tail and in due time it grows a new one.
Other lizards swell up, hiss and lash their tails as part of a defense program.