Bruce Kettler, age 10, of Peoria, Illinois, for his question:

Does an opossum sleep hanging upside down?

You don't often see a 'possum dangling by his tail from a bough. But chances are you can find a photograph of this remarkable sight in a nature book at the library. Notice that his bright round eyes are open. Obviously he is wide awake. He would never think of taking a nap in this upside down position.

The opossum takes his long nap during the daytime and, like most wild creatures, he takes care to hide himself while he sleeps. For one thing, his woodsy world is patroled by bobcats and foxes, hawks and a long list of other hungry fellows who enjoy opossum meat for dinner. His hideaway may be a deserted burrow or a hollow tree. An opossum named Gerald rents ,a small cavelet under a waterfall in Andy's backyard.

An opossum's little den is lined with a comfortable layer of crisp grasses and dry leaves. Naturally a mother opossum shares it with her brood of growing youngsters. But the adults prefer to live alone and usually a den is occupied by one male or one female. There he or she spends the day, curled up and fast asleep.

In the late evening, the opossum comes forth into a shadowy world. He pokes out his nose to test for whiffs of known enemies    and perhaps a few sniffs of suitable food. Soon his bright eyes are used to the darkness and he ventures a few careful steps from his door. If the world seems safe, he begins his nightly prowl for assorted meats and vegetables.

The opossum is a great tree climber. Sometimes he scrambles up in the branches to escape dogs and other blood thirsty opossum enemies. Sometimes he climbs up to gather berries and other fruit for desert  ¬especially persimmons. And sometimes he hangs onto a bough with his tail    and lets go. His head and fat furry body dangle upside down, while he watches what goes on in the shadowy night time world.

The opossum has a long, hairless tail that can wind around objects and hold on. It is called a prehensile, or grasping, tail. However, the tail of an older opossum tends to lose some of its grip. So, if you see an opossum dangling upside down among the shadowy branches, you can be fairly sure that he is a young fellow. And he will not go to sleep in this remarkable position.

The mother opossum gives birth to a dozen or more naked, helpless little babes. For about ten weeks they are fed from milk faucets in her pouch. Then they come out and cling to her fur while she goes forth on her nightly rounds. Life for the opossums is very risky and some of the broods are sure to be lost. At about 14 weeks, the survivors go off to find dens for themselves    and the lucky ones can expect to live about two years.