Danny Ching, age 9, of San Bernardino, California, for his question:

How lone can a beaver stay, under water?

Andy has a couple of beaver friends who live in Rocky Mountain National Park. So he zoomed off to visit them to see for himself just how long they can stay under water. While there, he also learned a few other interesting things about the beavers. The family home is built out in the middle of a pond. The front door is under water and the beavers have to swim under water to get inside.

It was spring time and the warm air was melting the winter snows from the tall mountain peaks. The poplars, the willows and the alder trees were sprouting their new green leaves. Merry little streams were flowing over the ground. And there by a quiet pool sat a big, fat furry beaver. As a rule, this fellow is almost as busy as Andy. But right now he was taking things easy    or so it seemed. Actually, he had just come out of his pond and was busy cleaning his thick fur and making it waterproof again.

He used the special scrapers on his back feet to wipe and comb himself clean and dry. (This also spreads oil through his furry coat    and oil repels the water.) The primping job took half an hour. Then the beaver was ready to start his busy daily chores. By this time, Mrs. Beaver had arrived from their home in the middle of the pond. She paused to watch the water where her two teenage children were swimming below the surface. They scrambled up on the shore and shook the water from their furry coats.

But Mrs. Beaver kept looking out toward the shaggy house in the middle of the pond. Pretty soon, two feathery ripples appeared on the water, moving toward the shore. They were made by the furry noses of the baby beaver twins. Before the summer was over, those young rascals must have learned how to swim under the water. Mr. Beaver had plans to cut down a young willow tree with the help of his teenagers. While they worked he taught them all the beaver tricks for doing the job just right.

Mrs. Beaver had swimming on her mind    underwater swimming. Perhaps she worried because those ripples would show a hungry fox just where to catch her chubby offspring.

So she led them back into the water, again and again. When they dived, special  valves closed to keep the water out of their ears and noses. But every time the beavers needed a breath of air they had to come to the surface. As the young beavers practiced, they learned to hold their breath longer and longer. They managed to stay below for two minutes, then three and then five minutes. Mrs. Beaver filled her lungs with air and stayed under water for 10 minutes. Then Papa joined the swimming lessons and proved that a big beaver can stay under water as long as 15 minutes. The teenage beavers also did some practicing. They tried to stay under water as long as Papa  ¬but could not match their father's prowess.

As a rule, the busy beavers spent most of their time on their building chores. They cut down trees and chewed them into logs to build and repair their dams, water ways and their home. They also spent a lot of time eating bark and cleaning their fur. But between chores, each young beaver learned how to stay under water 15 minutes    holding his breath all the time.