A beaver with shiny, brown fur is standing on its hind feet looking at the camera with its long flat, black tail on display.Description: Beavers, the largest rodents native to North America, measure more than three feet in length, and weigh up to 55 pounds, with a broad, nearly naked, flat tail and webbed feet. Their sign is familiar: dams, lodges, bank dens, canals, slides and of course gnawed stumps of aspen, alder, willow or cottonwood. It takes a beaver approximately 30 minutes to fell a 5-inch diameter tree. Beavers feed on the upper, tender branches, leaves and bark of trees. Many mountain ponds, willow thickets and meadows also are the works of beavers overtime. Beavers are active year-round. Their ponds provide navigable water beneath the ice. No mammal other than humans has a great an influence on its surroundings. This is a "keystone species" in riparian communities; without them the ecosystem would change dramatically.

As abundant as beavers are today, it is difficult to believe that once they were on the verge of extinction, trapped for their under fur, which was used to make felt for beaver hats. In the mid-19th century, silk hats replaced beaver felt as a fashion, and that probably saved the beaver from extinction. But, before it ended, the beaver trade opened the mountains of Colorado to European exploration.

Beavers are fairly well protected from predators by their large size and aquatic habits. Mink eat some kits, and coyotes can capture a beaver waddling on dry land. Aside from that, floods may be the largest cause of death. Beaver in Colorado are managed as fur bearers.

Range: The beaver lives throughout Colorado in suitable habitat, although it is most abundant in the sub-alpine zone.

Habitat: Beavers live around ponds and streams that are surrounded by trees. The beaver lives throughout Colorado in suitable habitat, although it is most abundant in the sub-alpine zone.

Diet: Beavers feed on grasses and forbs in the summer, and bark in the winter. Beavers eat the upper, tender branches, leaves and bark of trees. They do not eat the inner wood.

Reproduction: The den houses a nuclear family including parents, yearlings, and four or five kits. There is a single litter of young born each year, born in the spring after about a four month gestation period.

Frequently asked questions

A beaver with a large stick in its mouth is swimming toward a beaver structure.Is it legal to trap beavers?

Amendment 14 of the Colorado Constitution passed by the voters of Colorado in 1996 bans the use of leg hold and kill traps throughout the state. While the intent of the amendment was to stop lethal trapping, it also prevents the control of animals causing damage. There is an agricultural exemption which allows farmers and ranchers to trap beavers causing damage to their crops and property one 30-day period a year. But the vast majority of problems involve beavers damming up water ways and culverts or cutting down ornamental trees.

Are there non-lethal methods of dealing with problem beavers?

Colorado Parks and Wildlife suggests:

  • Wrap individual ornamental and fruit trees with fencing.
  • Use electric fencing around culverts.
  • Lessening the problems caused by their dams by using special pipes and grates.
  • Another option is to mix a concoction of five ounces of mason sand with one quart of exterior latex paint and apply it to the first 3 ½ feet of the trees.
  • Install a water level-control device which will allow the beaver to stay on location while water continues to flow downstream.

Are there any other options?

The only lethal option is to live-trap and then shoot them. Licensed trappers will live-trap beavers for a fee. They often have arrangements with private landowners or public land agencies to release live-trapped beavers.

It is illegal for private individuals to release live-caught beavers on public land.

Additional Information Resources

Colorado Parks & Wildlife on Beaver Problems

Beavers: Wetlands & Wildlife (BWW) is a tax-exempt educational nonprofit based in Dolgeville, NY with members in the U.S., Canada and overseas. Their website has several environmentally sound, cost-effective, long-term solutions for problems that arise between humans and beavers.  This nonprofit was created with the inspiration from Dorothy Richards who studied beavers at Beaversprite Sanctuary in New York’s Adirondack Mountains for fifty years. She welcomed over 100,000 visitors to her house, where two consecutive beaver families lived in an addition, called the “Y.”  As part of her lifework to enlighten the public about this important, but shy, species, she wrote Beaversprite, My Years Building an Animal Sanctuary with the help of Hope Sawyer Buyukmihci. 
King County, Washington website has a discussion of beavers -related problems and solutions for coping with the difficulties they present.