Its brown underfur is covered with long, stiff guard hairs, and its belly and head are lighter coloured. Its large gnawing teeth continue growing, and the Beaver must keep gnawing on wood to keep them at a proper length. Beavers have long, loose lips which they can draw behind their front teeth to seal them together. This allows Beavers to hold items in their teeth without filling their mouths with water while they are transporting branches or wood underwater. Beavers build dams to form artificial water ponds in areas where there is a good supply of poplar and aspen.
Beavers are active at all hours, but they can be seen mostly in the mornings or evenings.
They will work all night repairing or building dams or houses with twigs, mud, and logs. The entrance into the Beaver houses is always under water, and Beavers construct platforms inside above the high-water level. There platforms are used for sleeping, eating, and resting. The artificial water bodies created by the Beavers flood over trees, which causes them to die. This causes concern to many naturalists.