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.
Donkeys and mules are confused for each other often. Turns out they are both very different from each other. Can you tell these two apart?
Impala is a small East African antelope. The impala stands about 3 feet (90 cm) high at the shoulder and weighs about 150 pounds (68 kg).