Why Do Beavers Build Dams?
There are two kinds of beavers: the American and the European. The European beaver, found in Norway, Poland, Germany and France, lives in burrows. Whereas the American beaver builds a dam across a stream or lake to construct his home or lodge. The lodges are made of huge logs of trees.
Beavers build dams across shallow streams to hold back the water. The beavers then build their homes, or lodges, in the deep water that forms behind the dam. A home built in a pond protects a family of beavers from enemies and bad weather. Beavers work together in family groups.
The beaver uses the same lodge to store food as well as to raise its young too. Since lakes and rivers freeze in winter, the lodge becomes a refuge from preying animals. Due to its underwater entrances the beaver can come and go as it pleases under the ice. Beaver dams also act as channels to control the flow of water in a stream or lake.
They cut down trees with their sharp front teeth. They eat the bark and use the trunk and branches to build their dam. If a tree trunk is too long to drag to a pond, beavers must cut it into shorter pieces. A finished dam is a wall about three or four feet high.
These structures modify the natural environment in such a way that the overall ecosystem builds upon the change, making beavers a keystone species. Beavers work at night and are prolific builders, carrying mud and stones with their fore-paws and timber between their teeth. Beavers can rebuild primary dams overnight, though they may not defend secondary dams as vigorously.