These feet often measure 6 inches in length, and the spread of the toes is equal to or greater than the length as the beaver swims. Five toes with strong nails are found on the hind feet, including unique split toenail on one toe which serves the beaver as a comb for grooming. The front feet seem small in contrast to the hind feet. Beaver normally swim with their front feet held against their chest, and the large webbed hind feet provide the propulsion with the tail acting as a rudder. Guard hairs in beaver fur are 2 inches in length, overlaying a soft and dense underfur about an inch deep.
Colors vary from section to section, and from blonde colors to nearly black.
Both male and female beaver have large glands, called castors, beneath the skin on the lower bellies. These glands produce an oil which the beaver combs into its fur to waterproof it. This oil is also deposited by the beaver at selected locations as territorial markers or mating attractants in the spring of the year. Beaver have transparent eyelids which cover the eyes as the beaver submerges, enabling the beaver to see well when submerged as the eyeball is protected from abrasive particles suspended in the water. The ears and nose of a beaver have valves that close as a beaver submerges, preventing the entry of water.