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DJ Hannigan

A beaver takes a dip.

Shortly after the Lewis and Clark expeditions through the Rocky Mountains, the already lucrative fur trading business hired workers known as “Mountain Men” to trap beavers for the rodent’s valuable and useful fur. As more settlers moved into the area and gold became the attractant, that way of life was gradually eliminated.

The fad of beaver hats also gave way to silk and the mountain beaver population was able to regenerate. However, it was said that the North American beaver population was once more than 60 million, but as of 1988 was between 6 and 12 million. This population decline is attributed to continued desire for the beaver’s fur and for their glands, used as medicine and perfume. The beaver is also considered a nuisance because their harvesting of trees and flooding of waterways may interfere with other land uses.

According to the Colorado Parks and Wildlife website, “many areas that once supported beaver are now occupied by people, and conflicts may occur in the form of flooded roads and property, destroyed ornamental and commercial vegetation, and plugged storm drains and culverts. In such instances, management is needed to protect property and human safety, and control animal numbers as necessary.”

Beavers are the largest rodent in North America and are primarily nocturnal and semiaquatic. Adults can weigh an average of 50-70 pounds and be a length of over three feet. They are described as semiaquatic because they spend the majority of their active time in the water, but forage on land for food and shelter supplies.

Beavers have clear membranes that completely cover their eyes underwater, valve-like ear and nostril openings, webbed rear feet, thick fur that provides lightweight insulation and is highly water repellent, and flattened, scale-covered tails. Their powerful jaws and strong teeth make it easy for them to fell trees in order to build homes and dams, often changing their environment in ways few other animals can. In fact, the idioms “busy as a beaver” and “eager beaver” are synonymous with being industrious and hardworking.

People respond to the presence of beavers in a variety of ways. Some see them as an interesting and perhaps a slightly unusual member of the local wildlife community. Those directly affected by their “projects” may see them as malicious creatures out to destroy their property. Most people probably fall somewhere in between admiring the beaver’s industrious nature and being frustrated by its destructive habits.

Beavers need water to survive. They live in or around freshwater ponds, lakes, rivers, marshes and swamps. They live in lodges, which are small dome like structures made from sticks, grasses, moss and mud. They build their lodges on the banks of the water source just above water level. Some may have two entrances.

Beavers have slow growth and reproduction. They have a lifespan of about 8 to 10 years. Females normally don’t reproduce until age 3 and an average litter consists of three to four kits per year. Beavers live in colonies ranging in size from four to eight individuals, with five considered average for most active sites. Mating is monogamous and the adult female is the dominant family member and leader of the colony. Important activities such as lodge construction, dam maintenance and building the winter food cache fall to the female. Males assist with dam maintenance and keep an eye out for dangers and mark their boundaries with scent mounds to ward off other beavers who may want to encroach on their territory.

Adult beavers, due to their size, are only preyed upon by mountain lions and wolves. However, the kits can fall prey to mink, otter, fox, coyotes, bobcats, and bears. In areas where trapping is allowed, humans are the most significant beaver predator.

“In the past, beavers were harvested via traditional trapping methods but that management option was lost when Amendment 14 was passed in 1996. Beaver causing damage in agricultural situations that meet the trapping ban’s exemption can be trapped via a special permit issued by CPW. Beaver can be hunted on a small game or furbearer license and the season runs from October 1st through April 30th annually. In cases where beavers are causing damage to private property outside the hunting season, the landowner should contact their local Wildlife Officer as there are exemptions and other options to resolve the issue,” explained Ian Petkash, the Lake George Wildlife Officer with Colorado Parks and Wildlife.

According to the Beaver Institute, beaver ponds create wetlands which are among the most biologically productive ecosystems in the world. They increase plant, bird and wildlife variety, improve water quality, and raise salmon and trout populations. This is done by opening the tree canopy that allows sunlight to reach the water. Algae and aquatic plants grow and are used by microscopic organisms, which feed insects and they in turn become food for fish, birds and mammals. An entire food chain is created in a beaver pond.

“Beavers are what we consider an ecosystem engineer species. They directly modify their habitat through their behavior and this affects all other species that use riparian corridors. Most of the time, the habitat changes caused by beavers benefit those species around them including fish, amphibians, song birds etc. These same habitat modifications can cause damage to human infrastructure such as culverts, roads etc.,” Petkash said.

Beavers are fun to watch, if you’re lucky enough to see them — but keep your distance. If provoked or scared, the beaver could bite and could do serious damage. They will protect their colony. If walking or hiking in an area where beavers reside, keep your dog on a leash and don’t allow them to poke around lodges, dams, or along the banks of the water. Besides defending their territory, beavers can carry rabies.

Don’t try to approach or feed beavers. If you see one hurt or dead, do not approach or pick them up. Call Colorado State Patrol dispatch at 719-544-2424 who will notify CPW and they will take the appropriate measures.

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