Although the beaver has strong teeth and sharp claws, he is such a peace-loving animal that he never fights with his enemies. He works hard to build dams and homes where he can be safe away from them.
A full-grown beaver is two and a-half feet long, a foot tall, and weighs about 50 pounds. His hind feet are webbed like that of a duck and help him swim. His forefeet are like little hands. He has a brace when he sits or stands, and this is a means of announcing bad news.
When a beaver feels danger, he strikes the water hard with his tail, and this sound can be heard a long distance. Then every beaver disappears. If you surprise a beaver, he will run for his pond. He can sink and stay down for about 15 minutes. Any longer than that and he will drown.
Beavers get the urge to build dams when they hear the sound of running water. The main purpose of the dam is to provide an area of deep water to protect the baby beavers and to make a mud bottom where a winter's supply of eating timber can be stored under the ice. Trees with soft barks are the beaver's main food.
A beaver works alone to cut down a tree. He stands on his hind feet; and with his long, strong teeth he eats around the tree until a thin spike is left. Then the wind or the law of gravity brings the tree cracking down. If the tree doesn't drop into the water, he cuts it into smaller pieces and rolls it to the water.
Once a tree is set to start a dam, it catches drift wood. The beaver carries mud, sticks, stones, and grass in his small hands and works them into place. Beavers work mostly at night - almost never by day unless there is a break in the dam. As the dam goes up, each beaver couple begins to build a house or lodge on top of the dam. It is made of sticks and stones and mud and has two entrances through the floor under the water. Having two doorways is a good idea. If an enemy suddenly makes a call through one entrance, the beaver family quickly disappear through the other. A pair of beavers may take about six months to build a lodge unless freezing weather comes early. Then they can hurry and do it in a month.
Beavers live in close-knit families of parents and their young. The fully furred baby kits are born in spring in litters of two to six. Each will weigh less than a pound at birth. A baby looks like the adult beaver except that its tail is soft and covered with fine grey hair. Babies start bathing by the fifth day. Although they nurse for two months, the mother brings tender barks for them to eat when they are only a week old. After one month they can dive and swim and groom themselves without any help from the mother.
After a second group of kits is born, the parents drive away the first group. The older ones then go out to find mates and build dams and lodges of their own. Once they mate, they stay together for life.