Susan Mind, age 10, of Kinnaird, B.C., Canada, for her question:

Why does a lizard's tail fall off?

Every so often a snake sheds his shabby old skin. Every fall, most deer shed their proud antlers and grow new ones in the spring. A lizard may lose his tail. But this is not at all like animals that shed their skins, their antlers or their fur. These things happen at certain seasons.

When a lizard loses his tail, it does not make him more comfortable in summer or winter. But the loss may save his life. His world is full hawks and snakes, owls and foxes and many other animals that enjoy lizard meat. Often one of his enemies grabs him by his tail. It breaks off, and the rest of the lizard has a chance to escape. This is a nuisance. But in time his body grows a new tail.