Why do beavers build dams?
Beavers and their dams play an important role in nature. Because of the dramatic effects their dams have on surrounding ecosystems, these mammals are considered a keystone species. By constructing dams they create wetlands -- lush environments which attract fish, ducks, frogs and other creatures. However, beavers can become a big headache for farmers and landowners -- a problem we'll examine later in this article.