Beaver
Castor canadensis
Beavers have thick fur and their webbed feet and rudder-like tails allow them to swim about six miles per hour. Above, a beaver swims at the Virginia Living Museum in Newport News, Va., on Dec. 30, 2018. (Photo by Will Parson/Chesapeake Bay Program)
Two beavers eat on a canal lock in Great Falls Park in Potomac, Md., on July 13. Beavers are the largest rodents in North America ranging from 30 to 60 pounds and have teeth that continuously grow throughout their life. Because of their specialized digestive tracts, they are able to eat a diet of tree bark and leaves. Most noted for their ability to build dams, beavers live in lodges they create by cutting down trees. (Photo By Kaitlyn Dolan/Chesapeake Bay Program)
To protect their lodges, beavers build dams across streams to flood the area and create deep, quiet ponds. These ponds also allow beavers to safely transport food and logs through the water. Above, a beaver dam is seen at Greenwoods Conservancy in Burlington, N.Y., on May 23, 2015. (Photo by Will Parson/Chesapeake Bay Program)
Beavers regularly cut down trees to eat and to repair dams and lodges. A beaver can chew down a small tree in just a few minutes. Above, a fallen tree shows older marks of beaver activity along the Chemung River in Tioga County, N.Y., on Sept. 30, 2017. (Photo by Will Parson/Chesapeake Bay Program)
A beaver coasts through an enclosed section of Deer Park Lake at the Virginia Living Museum in Newport News, Va., on March 9, 2016. (Photo by Will Parson/Chesapeake Bay Program)
The paddle-shaped tail of a beaver can be up to 10 inches long. Beaver tails can also be used for balance while a beaver carries heavy tree branches in its mouth. Above, a beaver swims at the Virginia Living Museum in Newport News, Va., on March 9, 2016. (Photo by Will Parson/Chesapeake Bay Program)
The beaver is a large, brown, semi-aquatic mammal with a distinctive flattened, paddle-like tail. It lives in lakes, streams and forested wetlands throughout the Chesapeake Bay watershed.
Appearance
Beavers have thick, glossy brown fur and a large, scaly, paddle-like tail that can be 9 to 10 inches long and 6 inches wide. They have webbed feet and large, chestnut brown front teeth. Their head is rounded with small, rounded ears. The beaver's head and body grow to 25 to 30 inches long and usually weighs 30 to 60 pounds.
Feeding
Beavers eat mostly tree bark and leaves. Red maples, willows, alders, shadbush and redosier dogwoods are some of their favorite foods. They have specialized digestive tracts that allow them to digest tree bark. They also eat bay grasses, such as pondweeds, and the roots and rhizomes of aquatic plants, such as lilies and sedges. They store branches and stems in their lodges to eat during winter.
Predators
Adults have few predators; humans hunt beavers for their fur. Owls, hawks and otters may prey upon young.
Voice
Beavers communicate with each other via distinct whining, grunts, grumbles, and barks.
Western Soundscape Archive at the University of Utah J. Willard Marriott LibraryReproduction and Life Cycle
Beavers live in colonies that include an adult male and female and their young. Each colony of beavers has only one breeding female. Adult pairs are monogamous, keeping the same mate for life. Adults begin breeding between 2 to 3 years old and have one litter per year. Mating occurs in January and February. After four months, an average of 2 to 4 young (called kits) are born, covered in thick fur, weighing about one pound and having open eyes. Kits can swim within a week of birth and are weaned within 2 to 3 months. When they are two years old, yearlings (young born the previous spring) are driven out or leave their lodge. Beavers can live 11 years in the wild.
Did You Know?
- Beavers are the largest rodent in North America.
- Their large front teeth continue to grow throughout their lives. Beavers are able to close their mouths behind their front teeth so they can carry logs and sticks underwater.
- A beaver can chew down a small tree in just a few minutes. They will regularly cut down trees to eat and to repair dams and lodges.
- To protect their lodges, beavers build dams across streams to flood the area and create deep, quiet ponds. These ponds allow beavers to safely transport food and logs through the water. Ponds formed by beaver dams are important habitat for fish and waterfowl
- Their webbed feet and rudder-like tail allow beavers to swim about six miles per hour. Their large tails make a loud sound when a beaver dives underwater.
- Beavers can be confused with muskrats and nutria. Beavers are the largest of the three animals and have distinctive flattened paddle-like tails.
- Once treasured for their fur, which was used as a wind- and rain-proof fabric for hats, beaver populations were depleted until just a few pockets remained. In the early 1900s, hunting and logging regulations were put in place to help beavers recover.
- Primarily nocturnal, beavers are occasionally active in late afternoon.
Sources and Additional Information
- Chesapeake Bay: Nature of the Estuary, A Field Guide by Christopher P. White
- Wildlife Information: Beaver – Virginia Department of Game & Inland Fisheries
- Living With Beaver – Howard County, Maryland Department of Recreation & Parks
- Animal Diversity Web: Castor canadensis – University of Michigan Museum of Zoology
- North American Mammals: Castor canadensis – Smithsonian National Museum of Natural History
- Index of Species Information: Castor canadensis – U.S. Forest Service
- NatureWorks: Beaver – New Hampshire Public Television
Quick Facts
Species
Native
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Size
Head and body 25 to 30 inches in length; tail 9 to 10 inches long and 6 inches wide; weighs 30 to 60 pounds
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Habitat
Lives in forested wetlands and tree-lined streams, rivers, ponds and lakes. Semi-aquatic, meaning it spends time both on land and in the water. Builds lodges of sticks and mud on islands, river banks and shorelines. Some beavers live in burrows within river banks.
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Range
Found throughout the entire Chesapeake Bay watershed.
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Diet
Feeds mostly on tree bark and leaves; also eats bay grasses and the roots and rhizomes of aquatic plants
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Lifespan
11 years -
Status
Stable