Beaver Food and Feeding Habits
Beavers (Castor canadensis) are the largest living rodents
in North America, with adults averaging 40 pounds in weight and measuring more
than 3 feet in length, including the tail. These semi-aquatic mammals have
webbed hind feet, large incisor teeth, and a broad, flat tail.
Once among the most widely distributed mammals in North America, beavers were eliminated from much of their range in the late 1800s because of unregulated trapping. With a decline in the demand for beaver pelts, and with proper management, they became reestablished in much of their former range and are now common in many areas.
Beavers are found where their preferred foods are in good supply—along rivers, and in small streams, lakes, marshes, and even roadside ditches containing adequate year-round water flow. In areas where deep, calm water is not available, beavers that have enough building material available will create ponds by building dams across creeks or other watercourses and impounding water.
Beaver dams create habitat for many other animals and plants of Washington. In winter, deer and elk frequent beaver ponds to forage on shrubby plants that grow where beavers cut down trees for food or use to make their dams and lodges. Weasels, raccoons, and herons hunt frogs and other prey along the marshy edges of beaver ponds. Migratory water birds use beaver ponds as nesting areas and resting stops during migration. Ducks and geese often nest on top of beaver lodges since they offer warmth and protection, especially when lodges are formed in the middle of a pond. The trees that die as a result of rising water levels attract insects, which in turn feed woodpeckers, whose holes later provide homes for other wildlife.
The beaver’s incisors (front teeth) are harder on the front surface than on the back, and so the back wears faster. This creates a sharp edge that enables a beaver to easily cut through wood.
Like many rodents, beavers construct nesting dens for shelter and for protection against predators. These may be burrows in a riverbank or the more familiar lodges built in the water or on the shore (shown here). However, the basic interior design varies little and consists of one or more underwater entrances, a feeding area, a dry nest den, and a source of fresh air.
Food and Feeding Habitats
Once among the most widely distributed mammals in North America, beavers were eliminated from much of their range in the late 1800s because of unregulated trapping. With a decline in the demand for beaver pelts, and with proper management, they became reestablished in much of their former range and are now common in many areas.
Beavers are found where their preferred foods are in good supply—along rivers, and in small streams, lakes, marshes, and even roadside ditches containing adequate year-round water flow. In areas where deep, calm water is not available, beavers that have enough building material available will create ponds by building dams across creeks or other watercourses and impounding water.
Beaver dams create habitat for many other animals and plants of Washington. In winter, deer and elk frequent beaver ponds to forage on shrubby plants that grow where beavers cut down trees for food or use to make their dams and lodges. Weasels, raccoons, and herons hunt frogs and other prey along the marshy edges of beaver ponds. Migratory water birds use beaver ponds as nesting areas and resting stops during migration. Ducks and geese often nest on top of beaver lodges since they offer warmth and protection, especially when lodges are formed in the middle of a pond. The trees that die as a result of rising water levels attract insects, which in turn feed woodpeckers, whose holes later provide homes for other wildlife.
The beaver’s incisors (front teeth) are harder on the front surface than on the back, and so the back wears faster. This creates a sharp edge that enables a beaver to easily cut through wood.
Like many rodents, beavers construct nesting dens for shelter and for protection against predators. These may be burrows in a riverbank or the more familiar lodges built in the water or on the shore (shown here). However, the basic interior design varies little and consists of one or more underwater entrances, a feeding area, a dry nest den, and a source of fresh air.
Food and Feeding Habitats
- Beavers eat the leaves, inner bark,
and twigs of aspen (a favorite food), alder, birch, cottonwood, willow, and
other deciduous trees. Beavers also eat shrubs, ferns, aquatic plants, grasses,
and crops, including corn and beans.
- Coniferous trees, such as fir and
pine, are eaten occasionally; more often, beavers will girdle and kill these
trees to encourage the growth of preferred food plants, or use them as dam
building material.
- Beavers have large, sharp, upper and
lower incisors, which are used to cut trees and peel bark while eating. The
incisors grow their entire lives, but are worn down by grinding them together,
tree cutting, and feeding.
- Fermentation by special intestinal
microorganisms allows beavers to digest 30 percent of the cellulose they
ingest.
- When the surface of the water is
frozen, beavers eat bark and stems from a food “cache” (a safe storage place)
they have anchored to the bottom of the waterway for winter use. They also swim
out under the ice and retrieve the thick roots and stems of aquatic plants,
such as pond lilies and cattails.
This information was provided by the Washington State Department of Fish and Wildlife, Russell Link, and Michael Holmquist
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