Marilyn Gaines, age 11, of Visalia, Calif:; offer question:

Are there man eating clams?

No clam in the world has teeth, and a good sized man would need a lot of chewing before he could be digested. So, there are no man eating clams in the world. There are clams, however, which are a threat to a man's life and limb, These whoppers can drown a swimmer. But they would not be interested in eating him.

This granddaddy of the clams is also the largest of all the shellfish in the world. His shell is several feet wide and he may tip the scales at 4.00 pounds. Of course, it takes him many years to grow to be this size, but he has plenty of time. It is said that specimens have been found over 100 years old.

The giant clam is called the tridacna and he is a native of tropical seas. His long life is usually spent in the rainbow wonderland of a coral reef. There are tridacna clams off the shores of the East Indian Islands, off certain Pacific islands, in the Indian Ocean and in warm waters of the Australian coral reef.

All day long, the monster clam sits in his rocky garden letting the salty water run in and out of his slightly parted shells, Oxygen and bits of food are carried in with the salty water. The oxygen is used in the clam's breathing processes. The food is digested. Sometimes a sizable fish swims through the shell doors and the clam gets a hearty meal.

As we all know, a clam is famous for closing his mouth and keeping it closed, When he wants to keep out intruders, the taro halves of his shell are clamped together and held tight by a very strong muscle. It is no easy job to pry open the shells of even a little clam, much less a big one.

When the monster tridacna decides to close his mouth, not all the king's horses could pry them open again.

It is this closed mouth trick which gives the tridacna his bad reputation, For if a swimmer, perhaps a pearl diver, should touch the mighty shells by accident, they might very well clamp shut on his foot or leg. Nothing is going to persuade that clam to let go, The unlucky diver is trapped down there in the water until his friends come to help him.

They will have to use surgery to free him. A long sharp knife is plunged between the shells of the clam and the powerful muscle which operates the two shells is cut, This is fatal to the big clam, but the diver is freed, we hope in time, The shells of the big clam may then be taken up and polished to make a pair of lovely white planters or lamp fixtures,