It’s the middle of the night in the desert. A small lizard lies almost covered with sand. Only its head sticks out. It is using the sand like a blanket to keep its body warm during the cool night.
When the sun comes up, the lizard crawls out of the sand. It moves very slowly because it is still cold. It lies on a rock for a long time, letting the sun warm it. When its body is warm enough, the lizard dashes off to look for food.
Lizards and all other reptiles are cold-blooded. Their bodies get just as hot or cold as the air or water around them. If their bodies get cold, reptiles can’t move well. If they get too hot, reptiles die. So reptiles must spend their time playing hide-and-seek with the sun. If they are cold, they lie in warm sunshine. If they are hot, they hurry into the shade.
A reptile that lives where winters are cold moves more and more slowly as cold weather comes. The reptile curls up in the warmest hole it can find. Soon its body grows cold and stiff. It cannot move at all. Only when warm weather returns can the reptile move again.
Picture Credit : Google