ECONNECTION
Beavers, Part 2
by Karen Dusek

April is generally the time for the older siblings (usually two-year-olds) to leave home and find a place of their own, not an easy task in an area that is heavily populated with beavers. Some may have to travel up to 30 miles from their birthplace before finding a place to settle down with a mate. When they do, they will first mark their territory with scent mounds - piles of muck carried from the pond and then sprayed with a scent from the anal and castor glands located near the base of their tail. It has been theorized that the mounds serve as a personal ad, announcing to all other beavers who pass through the sex and general age and health of those living in the colony, warning other beavers that the territory is occupied and also, perhaps, letting them know if there may be any potential mates available. (Beavers mate for life but may seek out a new partner if the original one dies.) A single colony may build as many as 40 to 120 mounds. After making the mounds, the pair will begin constructing a dam and lodge. Occasionally, adults who are unsuccessful at finding mates will live alone. The average lifespan in the wild is 10 years.

Meanwhile, back at the lodge, when the beaver babies are about one month old, they begin to learn to dive, build and repair dams and gather food by mimicking the adults, although it is not until autumn that they start to do any real work. One of their jobs is to help cut branches and stick them into the bottom of the pond near the lodge, creating a "food raft" that will keep the colony nourished during the long, cold winter. They may also help to repair holes in the dam, since it is essential to the colony's survival that a certain water level be maintained.

In the natural environment, beaver dams help to keep wetland ecosystems healthy by slowing the flow of floodwaters, preventing erosion and raising the water table. The ponds they create provide important wildlife habitat, and the silt that collects behind the dams allows water plants to take root, eventually leading to the development of meadows that thrive on the fertile soil. Where the natural and human-built worlds overlap, however, a situation that is becoming increasingly common, beavers and their dams are often viewed simply as a problem that must be overcome.

In a handbook published by the Internet Center for Wildlife Damage Management (ICWDM), James Miller, USDA Fish and Wildlife Program leader, notes that in some southeastern states beaver damage is estimated at $3 million to $5 million per year "for timber loss; crop losses; roads, dwellings and flooded property; and other damage." Cropland and even bridges have been destroyed by flooding caused by beaver dams, which have been observed as long as 1,000 feet, and culverts and drain pipes "have been stopped up so badly that they had to be dynamited out and replaced," according to the ICWDM. Beavers can also transmit Giardia lamblia, a pathenogenic internal parasite, to humans in water. According to the ICWDM, short of trapping or shooting entire colonies, there is little that can be done to eliminate beavers, once entrenched in an area. Trapping with foothold, body-gripping and conibear-type traps is allowed in the Michigan Thumb area from Nov. 10 to March 31. Shooting is also allowed with a permit. (See the Michigan Department of Natural Resources Web site for more information at www.michigan.gov/dnr). A more humane alternative may be the Clemson pond leveler, made of PVC pipe and used to keep culverts open and controlling the level of beaver ponds. (See the ICWDM Web site at http://icwdm.org/handbook/rodents/beavers.asp.)

I am not a hunter, trapper or even a fisherman, preferring to live by the doctrine "live and let live;" however, I have been in situations where I have been forced to destroy animals that were threatening the health and well-being of my family and pets, such as rats, mice, flies, hornets, wood ticks, mosquitoes, etc. Sometimes, difficult decisions need to be made. However, I am not an advocate of trapping beavers. Death by this method is typically slow and painful. Because the traps are set underwater, after the beaver has been caught it dies by drowning, a process that may be prolonged since beavers are able to stay submerged for long periods of time.

It was trapping that caused the near-extinction of the beaver in the 1600s. With the European species almost wiped out to quench the public's demand for beaver skin top hats, settlers in the New World saw an easy way to make money. According to Hope Ryden, author of The Beaver (1986), finding and killing entire beaver colonies was a relatively simple task and the pelts piled up so quickly that they were sometimes destroyed just to keep prices inflated.

"By 1800 so few beavers could be found within what was then the United States that John Jacob Astor sent an expedition across Indian territory into Oregon Country to hunt the animal there…," wrote Ryden. "By the end of the 19th Century, every state in the Union declared the animal to be either entirely gone or nearly so."

It was only through careful management, which included reintroduction and laws banning trapping that beavers began to make a comeback.

Many cultures regard beavers, whose ancestors roamed the earth in prehistoric times, as more than just a commodity to satisfy human needs and greed. Laura C. Martin, author of Wildlife Folklore, tells us, for example, that the Cheyenne believed that the earth lies on a huge wooden beam. A white beaver that lives in the north country and is "father to all the animals," chews on the beam when it is "in a bad mood." Eventually, the beaver will chew completely through the wood and all living creatures on earth will "fall into nothingness."

I will leave you with that thought to chew on.

You may email Karen at karen@lakeshoreguardian.