The beaver is Arkansas' most controversial furbearer. Once exterminated from the state by unregulated trapping, beavers were re-established and are now found statewide. The beaver is the largest rodent in the U.S., reaching 4½ feet in length.
The average adult weight is 40 to 60 pounds. Beavers are well adapted for their aquatic existence. They're "bottom-heavy," with well-developed hindquarters and small chest and forequarters. Their huge hind feet are webbed and driven by large muscles that propel the beaver's streamlined body throughout the water.
The beaver's tail is large and flat. It's furred at the base, but is mostly covered with leathery scales. The tail is slapped loudly on the water to warn other beavers of possible danger. It also serves as a balancing platform when cutting down a tree on dry land or a rudder when swimming or diving. It's not used to move mud to the dam or lodge as some have claimed. Mud is clutched to the beaver's chest with its small hand-like front feet when transported.
Other adaptations make the beaver virtually waterproof. Valves in the ears and nostrils close when the beaver submerges, and its dense underfur is impervious to water. A split claw on each hind foot enables the beaver to evenly distributing waterproofing body oil when grooming and cleaning its fur. The beaver has large lungs and can stay underwater for up to 15 minutes.
Like all wildlife, beaver have both positive and negative wildlife values. Their unique ability to construct dams and create substantial water impoundments can drastically change the ecology of wooded areas and natural marshes.
Beavers are credited with creating some of the finest waterfowl habitat in the state. Mallards and wood ducks thrive in these areas, and deer may feed on aquatic plants growing along the edges. These same abilities create potential problems for humans, where flooding can damage roads, forests and farmland. In addition, beaver will fell ornamental shrubbery, fruit and shade trees for food when they have been planted near potential beaver habitat.