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Beaver

Castor canadensis

Beavers have thick brown fur and a distinctive flattened, paddle-like tail that can be 9-10 inches long and 6 inches wide. (Ryan Somma/Flickr)
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Beavers have thick brown fur and a distinctive flattened, paddle-like tail that can be 9-10 inches long and 6 inches wide. (Ryan Somma/Flickr)

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:

  • Thick, glossy brown fur
  • Large, scaly, flattened, paddle-like tail that can be 9-10 inches long and 6 inches wide
  • Webbed feet
  • Large, chestnut brown front teeth
  • Rounded head and small, rounded ears
  • Head and body grow to 25-30 inches long
  • Usually weighs 30-60 pounds

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. Within their lodges, beavers live in colonies that include an adult male and female and their young.
  • Some beavers live in burrows within river banks
  • 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.
  • Primarily nocturnal, but occasionally active in late afternoon

Range:

  • Found throughout the entire Chesapeake Bay watershed

Feeding:

  • Eats mostly tree bark and leaves
  • Red maples, willows, alders, shadbush and redosier dogwoods are some of its favorite foods
  • Has a specialized digestive tract that allows it to digest tree bark
  • Also eats bay grasses such as pondweeds and the roots and rhizomes of aquatic plants such as lilies and sedges
  • Stores branches and stems in its lodge to eat during winter

Predators:

  • Adults have few predators
  • Owls, hawks and otters may prey upon young
  • Humans hunt beavers for their fur

Reproduction and Life Cycle:

  • Each colony has only one breeding female
  • Adult pairs are monogamous, keeping the same mate for life
  • Adults begin breeding between 2-3 years old
  • Beavers have one litter per year
  • Adults mate in January and February
  • After four months, an average of 2-4 young (called kits) are born. At birth they are covered in thick fur, weigh about one pound and have open eyes.
  • Kits can swim within a week of birth and are weaned within 2-3 months
  • When they are two years old, yearlings (young born the previous spring) are driven out or leave their lodge
  • Can live 11 years in the wild

Other Facts:

  • The largest rodent in North America
  • Teeth continue to grow throughout their lives
  • Regularly cuts down trees to eat and to repair dams and lodges. A beaver can chew down a small tree in just a few minutes.
  • 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
  • Large tail makes a loud sound when a beaver dives underwater
  • Able to close its mouth behind its front teeth so it can carry logs and sticks underwater
  • 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 its fur, which was used as a wind- and rain-proof fabric for stylish hats. This caused beaver populations to become depleted until just a few pockets remained. In the early 1900s, hunting and logging regulations were put in place to help beavers recover.

Sources and Additional Information:

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