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  • Beavers are among the largest of rodents. They are herbivores and prefer to eat leaves, bark, twigs, roots, and aquatic plants.

  • Beavers gnaw trees with their strong teeth and powerful jaws to bring them down. They use the wood to build dome-shaped lodges and dams.

  • Beavers create massive log, branch, and mud structures to block streams and turn fields and forests into the large ponds.

  • They have valves in their ears and nose that close when they swim underwater.

  • The beaver's tail is large and shaped like a paddle. The black scaly tail is used for balance on land and works like a boat rudder to steer the beaver when swimming.

  • Beavers live and work in extended families of monogamous parents, young kits, and the yearlings born the previous spring.

Given the bad press that they typically get, beavers are too often viewed as a destructive -- albeit physically charming -- menace. To put exaggerated media hype about landscape damages in perspective, beavers need to be recognized as wetland architects and credited with creating and maintaining that essential habitat. Though not deliberate, they accomplish this feat as a side effect of the dams they construct to stop flowing water near their chosen lodge sites. Some creatures actually depend upon beavers’ habitat transformations for shelter. Pileated woodpeckers, for example, benefit by having more potential places for their cavity nests when redirected water floods treed areas. Countless species of amphibians, reptiles, fish, and invertebrates benefit, as well.

More than Meets the Eye

Most people are surprised by the size of an adult beaver. Though they are cousins to mice and squirrels, beavers are North America’s largest rodents, typically weighing 50 or more pounds. Somewhat awkward on land, they are adapted for living mostly in water. Their bulky bodies are designed to keep them warm in cold water. Webbed feet propel them easily underwater, and small forelimbs enable them to carry branches back to their lodge.

Much like water birds, beavers spend a significant amount of time grooming to maintain their streamlined, waterproof condition. They use their flat tails in several ways: slapped on the water, they warn other beavers of danger; turned while swimming, they serve as rudders; and propped behind beaver standing to gnaw trees, they provide added balance.

Beavers’ ears and nostrils close while they are swimming, and their eyes have clear membranes so they can see while swimming. Beavers do not have keen vision, though; for safety, they rely more on hearing---both in and out of the water. Their sense of smell helps confirm sounds and sights. Flaps on the sides of their mouths enable them to chew and carry branches with their mouths while underwater.

Sadly, trappers have hunted beavers for their beautiful chestnut to dark brown fur for more than 300 years. Trapping was at its heaviest in the 1800s. Thereafter, efforts were made to restore beaver populations, but they may never rebuild their earlier numbers.

Adapting to Many Habitats

The Great Lakes states and southern Canada are the heart of beaver country. In these areas, beaver lodges may reach heights of 10 feet above water and widths of as much as 50 feet at the base. Beavers have adapted to habitats as far north as the Arctic Circle and as far south as the Valley Wild Wildlife Sanctuary in Louisiana and Gulf of Mexico, and from the desert Southwest as far east as the Maine north woods. Basically, anywhere both water and trees can be found, beavers may take up residence. Their flexibility stems from their unusual ability to modify their environment to meet their needs, particularly the ability to alter water levels. Lakes, creeks, and slow-moving rivers are the ideal sites for beavers, but some will settle for human-made ponds, irrigation ditches, or drainage ditches, as long as there is nearby vegetation to eat.

Modifying the Landscape

Though beavers are notorious for their ability to cut down trees, they are merely trying to fulfill their need for food and material to build their dams and lodges. Typically, their lodges are built or overhauled in late summer or early fall. While small trees come down with a few well-placed chomps, beavers sometimes work for multiple days or even weeks to fell larger trees. If there are not enough nearby trees to build a lodge, beavers will establish a bankside den.

Dams are beavers’ main means of controlling water levels. They try to block or slow the flow of a stream or river to create a stable water level for the colony site. As the water level rises, streamside vegetation is flooded. Food is then more accessible and the beavers are able to build a lodge that will not be washed away. They also create networks of canals, channels, and plunge holes to provide for safer movement to feeding areas.

Finding a Peaceful Balance

In truth, beavers are only reclaiming floodplains their ancestors once occupied. Perhaps it would be better for all if we left some of these places to nature. When that is not a workable option, it is possible to preempt or counter beaver activity effectively without removing or harming the beavers. Any of a variety of devices called beaver “bafflers” or “levelers” can be used to control water level, and wire guards, fences, and repellants can be used to protect trees. In fact, HSUS consultant Skip Lyle, with help from other staffers, has constructed his Beaver Deceiver™ devices in communities across the country---from Washington State to suburban Washington, D.C.---and even as far away as Poland!

With the loss of wetlands an ecological concern of national importance, we should allow beavers to play their natural role in reestablishing and maintaining wetland habitat wherever possible. As a matter of strategy, the human effort and expense that would otherwise be required to accomplish these goals could then be directed toward humanely excluding beaver activities in specific areas that we choose to manage for our own uses. Finding that balance will benefit humans, beavers, and the web of life they help support.

Helping to Protect a Wetland Habitat

Together with several other nonprofits and individual donors, the Humane Society Wildlife Land Trust helped the Unexpected Wildlife Refuge (UWF) purchase additional land that provides prime beaver habitat in New Jersey’s Pine Barrens. The land adjoins a parcel already under the protection of the UWF, sharing more than 1,000 linear feet of Main Lake Branch, downstream from Miller Pond. The UWF now protects 610 acres of undisturbed land in the area, permanently providing sanctuary for all indigenous animals.

If your land is home to American beavers, please keep in mind the important role beavers play in reestablishing and maintaining wetlands.


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