Like LODGES, Beavers also build dams. Beaver dams are created as a protection against predators, such as coyotes, wolves and bears, and to provide easy access to food during winter. Beavers always work at night and are prolific builders, carrying mud and stones with their fore-paws and timber between their teeth. Because of this, destroying a beaver dam without removing the beavers is difficult, especially if the dam is downstream of an active lodge. Beavers can rebuild such primary dams overnight, though they may not defend secondary dams as vigorously. Beavers may create a series of dams along a river.

Dams alter the flow of rivers and can flood hundreds of acres. Dams prevent erosion and raise the water table, which helps purify the water as silt builds up and breaks down toxins. As sediment and debris build up, carbon increases and nitrogen decreases. The chemical changes alter the type of invertebrates, and the new water source attracts new species of birds, fish and amphibians. Flooded timber dies off and a forest becomes an open water ecosystem. (2)

Beaver ponds, and the wetlands that succeed them, remove sediments and pollutants from waterways, including total suspended solids, total nitrogen, phosphates, carbon and silicates. (3)

Beavers do not hibernate. They continue to eat and build throughout the winter.