... beavers build dams?
A beaver's home, called a lodge, is built on an island of mud, stone, and twigs, and to keep
out unwanted visitors, it is built with an underwater entrance. If this structure were built in a regular pond,
the lodge might be flooded in the rainy season when the water rises and might have its entrance exposed
during the dry seasons when the water recedes. To prevent this from happening, beavers build dams
downstream of their lodges to keep the water at a constant level.
