Beavers Making a Slow Comeback
Vol. 3 Issue 2, Spring 1998
By Dave Harrelson
A Look at the Life of a Beaver
During the early years of the United States, one of the most important “currencies” was the beaver pelt. The trade in beaver hides was tremendous, and eventually the population of this species, Castor canadensis, plummeted from an estimated 60 to 100 million to a mere fraction of that amount. In fact, numbers of beavers became so low that many states had reintroduction programs to help reestablish local populations.
In Virginia, the beaver population has been growing slowly. Beavers have been the subject of news articles in northern Virginia on several occasions, usually about homeowner complaints concerning beavers building dams on streams in residential areas and fears about flooding of backyards and roads.
Beavers are rodents, related to squirrels, woodchucks, and gophers. They grow to a body length of 3 to 4.5 feet, and adults may weigh up to 70 pounds, though 40 pounds is the average. They are herbivorous animals whose favorite foods are the bark of trees. Beavers never eat fish, though many people think they do.
Because of their building habits, beavers are known for their engineering abilities and often are characterized as industrious — “busy as a beaver.” All sorts of place names, such as Loudoun County’s Beaverdam Creek and Reservoir, honor this hard worker, and many stories, fables, and myths in America’s heritage are associated with it.
Beavers are probably best known for building dams across small streams and creating a flood pond in which they build a lodge. In the absence of a dam or an appropriate site for a lodge, beavers will dig a burrow along a stream bank. Their dams are generally three to five feet high and vary in width from a few feet to several hundred feet. They build their lodges in or beside the ponds created by the dams. The lodges, like the dams, are built of sticks and rocks packed with mud, and there may be several in a large pond.
Each lodge contains rooms with a floor above water level. There usually are several entrances, typically at the bottom to provide protection from predators and, in winter, an ice-free route to and from the lodge.
Beavers build canals to float logs and branches in to the pond for use in construction of dams and lodges, to transport food stores, and to connect adjacent ponds or divert water. Their canals generally are only 18 to 24 inches wide and slightly over a foot in depth, but, like the large beaver dams, may be several hundred feet long.
Though the economic importance of beavers in the fur trade has diminished, this animal is still extremely important to our economy in other ways. Generations of beavers formed much of the landscape in which we live. Beaver dams slowed stream waters, which then lost their burden of silt. Over time the silt helped to develop much of the rich agricultural soil of our area.
Today, beaver dams still help retard the flow of excessive sediments into waterways such as Goose Creek, Broad Run, and the Potomac River. Beaver dams help to control natural water flows and thereby reduce the potential for flash flooding and washouts when rains are heavy and store water during times of drought.
Beavers are part of our natural landscape and heritage. They deserve our respect, or at least our tolerance.