• by Ann Bennett

Nature's Environmental Engineers

Tales of New Hampshire's Beavers


Beavers are the stuff of legends, predicated on their prodigious work habits and other admirable traits. Castor canadensis is the largest rodent and only land mammal with a broad flat tail, and next to man, is the mammal that alters the environment most to suit its needs. Though functional on dry land, beavers are better known for their aquatic feats, building and repairing dams, lodges, canals, and tunnels.

No other animal has played so romantic a part in American history, figuring prominently in folklore, myth, and history. Many Indian tribes venerated the beaver, paralleling its origins to their own. Cherokee legend contends that the Great Spirit, with the help f gigantic beaver, created the earth, and the Crow believed that each beaver was an Indian reincarnate, in all probability a friend or relative.


Without a doubt, beavers possess a variety of appealing habits from a human viewpoint. They are a meticulous animal, and spend a great deal of time grooming their coats, though the purpose is as much to waterproof their fur as to keep it clean. Family oriented, and for the most part monogamous, beavers mate for life. They are extremely protective of their young, too, and keep kits in the den until their second season. Under ideal conditions, where food is abundant, beavers coexist in separate but neighboring quarters. Left to their own devices, they build a benevolent, self-contained society.


The modern beaver is a direct descendent of the prehistoric Castbroides of a million years ago, the largest rodent ever to roam the earth. The prehistoric beaver reached fantastic weights of 700 pounds or more, though the animal of today rarely exceeds 60. Classified as rodents because of their dental configuration, beavers are the sole members of the family Castoridae.


The modern beaver's fare of choice is young aspen, alder, birch, maple, and other tender vegetation, and when the animal settles into an area, food supply and the proximity of water are the key considerations. In classic cases, saplings are quickly cut, slides created, and a dam built to impede the flow of a small stream -- which backs up the water to a level sufficient so the animal can swim to its food source. In time, a lodge is constructed of sticks and mud to weather the cold, and enough fodder stored underwater to last through the winter.


A beaver's life expectancy is 14-16 years, and it is a prolific breeder. Each spring females give birth to 2-6 kits, which remain within the family unit until their second year. Afterwards, yearlings are expelled to head off house hunting, and if the habitat is not sufficient, beavers have been known to travel remarkable distance in search of a new home.


Beavers once ranged across the globe, and today are found in Europe, Asia, and throughout most of the North American continent. The beaver, being a mammal, is an air breather, even though it spends more than half its life in the water. Special adaptations permit it to stay submerged for long periods, sometimes as long as 15 minutes at a time.


Another unique feature is its two perineal scent glands, or castors, with are filled with a rich, thick, oily liquid. This castoreum is used by the beaver for waterproofing its fur, as well as a means of communication. Castoreum has long been used by man as a medicine, and once was considered a cure-all for such varied ailments as colic, rheumatism, arthritis, and many others. It is still used as the base for some expensive perfumes.


The beaver's best known characteristic, however, is a large, flattened, broad tail, and when this appendage can be seen, it rules out confusing the animal with any other in the world. The tail length of a large specimen will measure 16 to 17 inches overall, and the base is covered with the same fur as the body. The flattened portion, on the other hand, measures a foot in length, 6 inches in width, and is covered with scales and sparse, bristly hairs. The tail serves as a rudder while swimming, a prop while the beaver sits upright to feed or work, and can deliver a resounding slap to warn of impending danger.


But it was the beaver's luxuriant pelt that first lured trappers into the North American wilderness, leading to enterprises like the Hudson Bay Company (founded in 1669), and the establishment of the Astor fortune. It was beaver skins, too, that brought white men and Indians into the greatest contact and conflict, as explorers first traded for the pelts, and later fought to take control of the land itself.


This evolutionary process is mirrored by the history of New Hampshire, which to a very large extent was founded on the beaver trade. Trappers traveled north from the seacoast region to trade with the Abenakis and discovered mountain valleys and river intervales rich with beaver. During the early 1700s, beaver pelts were used as the commodity of exchange in the Granite State.


In any event, the beaver's peaceful existence collided with the fur trade. The most common use of pelts was the manufacture of beaver hats, the height of fashion in 19th Century Europe. During this period — after the invention of steel traps, and before new felt making processes depressed the prices of a beaver pelt dramatically, hundreds of thousands were traded annually in North America. The Hudson Bay Company alone traded more than 3 million in the years 1853-1877.


It is not surprising that complete extinction was predicted for the species, but by the late 1800s a beaver preservation movement grew up comparable to the present day effort to save the whales. 'The result was a limitation on trapping seasons, as state after state passed laws giving the beaver complete protection.


As so often is the case, the pendulum has swung back the other way, and while beavers may not be a common sight in the North Country, they exist at "nuisance levels" in much of the Granite State, according to N.H. Fish and Game biologist Eric Orff. "The animal has made a dramatic recovery," he noted. "Today, all available habitat in New Hampshire supports beaver colonies. The numbers in Mt. Washington Valley and the northern White Mountains may not seem that great because it is not the animal's primary habitat," he continued. Orff noted that towns like Bartlett and Albany record only a handful of beavers during trapping season, while as many as 100 are taken annually in towns in southern N.H. counties without making a dent in the population.

Beavers are one of the animals the Fish and Game Department tries to manage "very diligently," according to Orff. "Beavers offer a spectrum of benefits to the ecosystem," he explained. "The ponds their dams create control spring runoff, and the ponds nurture other species." A vivid illustration, he added, is the documented correlation between beaver population levels in New Hampshire and those of wood ducks and otters, which both dipped radically in the late 1800s. Their levels returned hand-in-hand during the course of the last century.


In the wild, beavers are a model citizen, concurs. John Lanier, U.S. Forest Service wildlife biologist in the White Mountain National Forest for the past 15 years. "Beavers are an invaluable resource," he stated. "Their ponds act as sediment traps, catching and controlling spring runoff. As time goes on, aquatic life increases, and the situation becomes more conducive to other life forms," Lanier explained. Though the water stagnates, this means that all sorts of insects and birds move in. Eventually the beavers clean out the food supply and leave, the dam breaks from lack of repair, and the pond bed, which is very fertile, grows back into alders -- and the whole cycle starts again. "It's a continuous process, and a case of learning a lot from nature if we take the time to pay attention," Lanier stated.


Current population levels require an active effort on the part of Fish and Game to channel the animal's activities. One method is to install "beaver pipes", which control water levels despite the beavers' best efforts. "Trapping is the other integral part of the management process," stressed Eric Orff. "It's a matter of trying to keep the numbers down to healthy level, and not trapping is the worst thing you can do. Beavers are very territorial animals," he explained, "and when yearlings are pushed out on their own, and there's nowhere to go, you start finding them in peculiar places — wandering along the highway, or building dams in culverts where no one wants them."


As a result, the season on beavers is a lengthy one in New Hampshire and has been for the past decade. This year trapping is legal from December 1-March 15 in Carroll County, and November 1-March 31 in the rest of the state. The exception is Coos County, where limited numbers dictate that only the month of March is open for beaver trapping.


Orff pointed out that trapping is also an important part of the state's economy. In the boom years of the late 1970s, particularly 1979, it funneled three-quarters of a million dollars into New Hampshire. The price of beaver pelts peaked that year at $50, and 6500 skins were tagged. By comparison, the cost bottomed out last year at $15, and only 3000 animals were taken for their fur, netting $300,000.


This is an unfortunate turn of events from Orff's perspective, since it leaves the Fish and Game Department with few alternatives. "There's little point in live-trapping the animal and moving it elsewhere, since most of the available habitat in the state is occupied," he stated. The final recourse is simply to shoot the excess population, and Orff estimates that 1000 animals will be destroyed this year by Fish and Game officers just to keep their numbers in check.


The final ironic twist is that while beavers are firmly established in New Hampshire, John Lanier contends that the long-term outlook is less favorable. "Several factors are going to put a squeeze on the animals," he explained. "First is the natural transition statewide from field back to forest, poplars giving way to northern hardwoods and eventually to pines. In time this trend will severely limit food sources." The other essential element is manmade. "Wetlands are being developed at a frightening rate, which cuts back available habitat even further," continued Lanier. "At present, they are more than holding their own, but over a period of decades we are going to have to work at keeping beavers in New Hampshire."

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