Anyone spending much time around a lake, pond, river, or creek has surely seen the telltale signs of beaver-felled trees or mounds of sticks and logs protruding above the water. This rodent, the largest in North America, is found throughout Oklahoma where suitable habitat is available.

Though usually brown in color, the beaver's fur can range from a light chestnut to near black. Occasionally, several variations occur within the same colony. Adult beavers, both males and females, average 40 inches in length and weigh from 35 to 65 pounds.

Because of its large hind legs and short forelegs, the beaver waddles awkwardly while on land. Its long, heavy claws facilitate digging and also offer great dexterity, allowing the beaver to fold individual leaves into its mouth or to rotate small, thin stems as it gnaws on bark.
The beaver (Castor canadensis) is also characterized by its webbed toes and flat, paddle-like tail, which is hairless and covered in uncornified scales. The tail serves many purposes, including functioning as a prop while sitting. Beavers also slap their tails against the water to warn against danger, and they also use them for steering and swimming.

Further facilitating the beaver's aquatic lifestyle are its valvular nostrils and ears, which shut tight when submerged. It also has a third eye membrane that allows it to see while submerged. Its waterproof fur consists of long, coarse guard hairs and a short, soft undercoat.

Beavers are also known for their castor glands, which are located near the tail. They use these glands to scent-mark territory. Humans use this scent as a base aroma in many perfumes.
Beavers are monogamous and produce only one litter per year, usually in late spring or early summer. A typical litter contains three to four young beavers, called "kits." The fur of newborn kits may vary in color as much as that of adults, though it is usually reddish or cinnamon brown.

A typical colony of beavers usually has five or six members consisting of an adult pair and their kits from the previous litter. Young beavers will either leave voluntarily or be driven off by the adults before the second litter is born.

Beavers often build enormous lodges of sticks and logs which protrude above the water. These conical lodges feature underground passages to the den, enabling a beaver to enter and leave the den while submerged. This offers protection from predators like coyotes. These mammalian engineers will also build dams, similar in construction to lodges, which serve to maintain a constant water level in the animal's living area. A consistent water level ensures that the entrance to the lodge remains underwater, and it also maintains a proper depth in the canals, or "runs," which are built to make it easier for the beaver to seek vegetation away from its lodge.

Favorite foods for the beaver in Oklahoma are cottonwood, willow and Johnson grass roots, but they'll eat almost any type of bark, bud, root and leaf. Though a beaver can hold its breath for up to 15 minutes during a dive, it is often seen cruising the surface of a lake or pond carrying sticks or twigs in its orange-tinted front teeth.

Although they can cause flooding and damage to ornamental and crop trees, beavers also perform a valuable service to farmers and sportsmen by helping to control erosion. With their dams, they also create wetland habitat for waterfowl and other wildlife.

With its dedication to hard work and its ingenious structural designs perfected over millennia, it's no wonder that the beaver is considered the master engineer of the animal world.