Suzanne Cook, age 14, of Louisville, Kentucky, for her question:

What is the life span of a walrus?

This jumbo of the frozen north is on the list of mammals threatened with extinction. Sad to say, we don't know him as well as we should. Science teams trying to protect him are also studying the details of his life. No one is sure of his normal life span. But in his present hazardous situation, the chances of any walrus dying from old age seem pretty slim indeed.

In the past, Eskimos used harpoons, skill and lots of courage to kill walruses, one by one as needed. They ate his meat and made fuel from his fatty blubber. They also used his very thick, durable hide to cover tents and boats, to make ropes, dog harnesses and other leather goods. But his most valuable contribution was a pair of tusks, measuring two feet or more. This hard, smooth walrus ivory was carved into tools and artistic objects.

In those days, walruses were plentiful throughout the Arctic Ocean, around its icy shores and on lonely islands. The huge herds frequented the coast of Labrador, Sable Island and as far south as Massachusetts. Those taken by the Eskimos were not a serious threat to the total walrus population. But those days are gone forever. We regret to report that this gentle giant may become extinct. It is almost as regretable that this could happen before scientists have studies the details of his life in his natural environment. We do know that the female bears one pup in two years. He depends entirely on his mother until the tusks he needs to gather food are three or four inches long. Some of the youngsters fall prey to their natural enemies, the polar bear and the killer whale. Hence the herd increases slowly.

The males that survive mature at the age of five. The females are ready to mate at four and bear their first pups about a year later. We do not know the average life expectancy of the adults in nature. But we do know that man the hunter has certainly reduced their chances of reaching old age. The walrus is protected by Canada and Norway, Holland and Russia    but conservation laws are hard to enforce in the desolate northland. Ruthless hunters still gun down the large adults because these animals have the largest ivory tusks.

A walrus census of 1966 estimated the survivors to be around 25,000 and the yearly kill to be about 2,700. At this rate of slaughter, the herds cannot increase fast enough to survive much longer. Research teams in the Arctic are marking individuals to study their migrations and other habits. It is hoped that this information, plus stricter protection might, just might preserve the walrus from extinction.

A bull walrus may reach a length of 12 feet and weigh 1 1/2 tons. His ivory tusks are about two feet long and past specimens were known to have three foot tusks. The cow walrus is smaller and her tusks are slimmer. But at present; we cannot say how old these large adults are    or guess their average life expectancy.