Editor’s Note: This is the first of two articles dealing with beaver management. Next week’s article will discuss ways to prevent beaver damage.
Beavers (Castor canadensis) are the largest rodents in North America.
Their range includes most of North America, from the northern parts of Canada and Alaska to northern Mexico.
Beavers are aquatic rodents which live in rivers, streams, ponds, lakes or other wetland areas.
In Texas, beavers are very abundant and it is not uncommon to find beavers in urban and suburban areas.
Beavers live in “lodges” built at the water’s edge or farther out in the water. They usually enter and leave the lodge through an underwater entrance. However, not all beavers construct and live in traditional stick lodges. In some places, beavers will dig burrows in the steep banks along rivers, streams, lakes or ponds.
Beavers use established trails when traveling to and from feeding areas.
They usually swim in the same places along the pond bottom. These underwater paths soon develop into depressed or grooved areas called “runs,” and are about a foot in width.
Beavers also crawl in and out of the water at the same places, and after a period of time these areas develop into “slides” or smooth places at the water’s edge. The presence of runs and slides is a sure sign that beavers inhabit an area.
Beavers feed on a variety of vegetation, but the cambium layer of “soft wood” trees is their principal diet.
During the winter, beavers depend on trees such as willow, cottonwood, sweetgum, pine, and most nut and fruit trees.
During the summer, beavers eat herbaceous aquatic plants, feeding on the basal portion of semi-aquatic grasses, sedges, cattails, water lilies and trees.
Beavers increase their tree cutting during the fall as they build up their caches of food for the winter months.
Beaver dams stabilize creek flow, slow run-off and create ponds which benefit fish, fur-bearing animals and other wildlife. However, when a beaver’s modification of the environment comes in conflict with man’s objectives, the results may be more damaging than beneficial.
Beaver pelts from the northern and central parts of the United States are used extensively in the manufacture of ladies’ coats and as a trimming for other fur or cloth coats.
Beaver pelts also are used in making hats. Southern beaver pelts, however, are of little economic importance because of their low-quality fur.
Most of the damage caused by beavers is the result of bank burrowing, dam building, tree cutting or flooding.
Levees or pond dams weakened by beaver burrows may collapse during periods of high water. If creeks, drainage ditches, culverts and spillways become blocked by beaver dams, adjacent pasture land, timberland and roadways can be damaged by flooding and erosion.
Beavers can damage boat docks and fishing piers by building their lodges underneath them.
Beavers also can cause extensive damage to agricultural crops such as corn or sugar cane, although their damage is more commonly inflicted on trees along rivers, streams and lakes.
In urban areas, beavers damage fruit trees, gardens and ornamental trees and shrubs.
Biology and Reproduction
Adult weight: Average 40 to 45 pounds.
Total length: Approximately 3 and a half feet.
Color: Uniform dark brown with lighter underparts.
Tail: Large, flat and furred at the base.
Feet: Webbed hind feet.
Gestation period: About 128 days.
Litter size: One to four kits, average two to three.
Number of litters: Single litter usually born in April, May or June; some females may produce a second litter in August or September.
Life span: 10 years in the wild; 21 years in captivity.
Social structure: Established beaver colonies generally consist of four to 10 related beavers. Young beavers are commonly dispersed from the colony shortly after they become sexually mature, at about 2 years of age.