Patricia Caldwell, age 13, of Aaughton, La., for her question;

Which animal lives longest?

A young deer may be shot by a hunter and a cheerful frog in the prime of his life may be gobbled up, or rather down, by a hungry heron. So when we consider the time an animal is likely to live, we must allow for accidents. The likely age limit for each animal is ca11ed its life span.

The life span of a rhinoceros is about 52 or 53 years. This means that, if he is lucky enough to avoid fatal accidents and illnesses, he may expect to live long enough to celebrate 52 or 53 birthdays. But the life span varies among individual animals just as it does among individual people. Members of the very same family may have longer or shorter life expectancies.

We must keep these variations in mind and allow a few less or a few more years for individual cases. Biologists can only estimate the average life span of this or that species. What's more, the animals most easily observed are those in captivity where they tend to live longer than they do among the hazards of the wild.

Rats and mice live only 2 or 3 years and a wily bare may live to celebrate 6 or 7 birthdays. A reindeer is an old timer before he is 12 and a wolf is ancient at the age of 13. The sassy woodpecker has a life span of 15 years, 5 years longer than the mighty lion. geese, parrots and swans often live almost half a century and an elephant may reach is 58th birthday.