The lodges are made of sticks, mud and rocks. In faster rivers and streams, beavers sometimes build lodges into the sides of banks. Some lodges are large enough to fit a human being inside of them. The living area is well insulated by the lodge and surrounding water, so the temperature is considerably warmer inside the lodges than outside. Lodges can have several entrances that are usually underwater.
Beavers are incredibly beneficial to the environment.
They are instrumental in creating habitats for many aquatic organisms, maintaining the water table at an appropriate level and controlling flooding and erosion, all by building dams. Although beavers are beneficial to the environment, they can destroy it also. Dams slow the flow of water in fast streams, changing the flora and fauna and sometimes creating silting. The conservation status differs with respect to source, but there have been significant threats to the survival of the beaver. Beavers have been hunted and trapped extensively in the past and by about 1900, the animals were almost gone in many of their original habitats.