Dams, canals and lodges

Beavers are known for their natural trait of building dams on rivers and streams, and building their homes (known as "lodges") in the resulting pond. Beavers also build canals to float build materials that are difficult to haul over land. They use powerful front teeth to cut trees and plants that they use for building and for food. In the absence of existing ponds, beavers have to construct dams before building their lodges. First they place vertical poles and then fill between the vertical poles with a crisscross of horizontally placed branches. They fill in the gaps between the branches with a combination of weeds and mud until the dam holds back sufficient water to surround the lodge.
(Thanks, Wikipedia)