Bobby Stockdall, age 11, of Springfield, Oregon, for his question:

Can whales breathe air like other mammals?

All the mammals have lungs for breathing air. None of them can breathe under water, not even the seagoing whales and seals. A big whale can stay way down under the water for half an hour or more, but only for as long as he can hold his breath. Then he must come to the surface for the next breath of air. He spends a long time puffing out a steamy fountain of stale air from his huge lungs. Then he fills up with fresh air and goes below again.

The dolphins and the playful porpoises are smaller members of the whale family. They, too, are mammals and must surface to breathe air. The seals are seagoing mammals of another group. They, also, must come up for fresh air, usually after about five minutes. Though these charm¬ing animals are very much at home in the water, they spend a lot of time lolling on rocky beaches, where breathing is no problem.