Castor canadensis

Beavers are our largest rodents. They have big bulky bodies, rounded heads, and small eyes and ears.

Beavers have dark brown fur and a large, flat, scaly tail. They also have large, orange front teeth. Beavers' hind feet are black and webbed.

These mammals can grow up to four feet long and weigh 60 pounds.

Beavers can be found just about anywhere there is water, including: marshes, ponds, lakes, rivers, and streams.

Beavers are well-known for their construction. They build dams and lodges using sticks, branches, saplings, reeds, rocks, and mud. Dams can be forty feet long and ten feet high.

Lodges are dome-shaped homes, built up to six feet high. They have one or more underwater entrances, and a hollow area near the top where the Beavers live.

Beavers also make "scent mounds." Scent mounds are small one-foot tall piles of mud, sticks, sedges, and grass. Beavers leave their scent on the piles to mark their territory.

Copyright, Don Getty, California Academy of Sciences

Wildlife Services Image Collection

Beavers are active throughout the year, but are mostly nocturnal (most active at night).

Beavers are excellent swimmers and can stay underwater for 15 minutes at a time. They are able to close their nostrils and ears to keep water out. Their eyelids are clear so they can see underwater!

To construct lodges and dams, Beavers will take down trees. Usually they are small trees, but sometimes, especially if there aren't smaller trees around, they will take large ones.

To do this, the Beaver will use its large front teeth to bite chips off the trunk, while working its way around. Beavers' lips are behind the front teeth, so they can close their mouth while they work on a tree!

Once a tree has been felled, the Beaver will trim off the branches and drag/carry it to its construction site.

Sevilleta LTER

Wildlife Services Image Collection

Beavers don't just use trees for building, they also eat them. Many of the same tree species they take down for construction are used as food. These include: willows, maples, hickories, Sweetgum, American Beech, birches, and aspens. Beavers eat the bark and soft wood just underneath the bark (called cambium).

Other plants eaten by Beaver include: pond lilies, sedges, pondweeds, algae, ragweed, ferns, duckweed, Witch Hazel, and other shrubs, weeds, and aquatic plants.

Beaver prefer smaller plants, rather than bark and wood from trees. They get their food from trees mostly in the Winter when other plants aren't available.

Beavers mate in late January and February. Litters of two to four are born in May and June. Young Beavers stay with their parents for two years before they are forced to leave.

Beavers mate for life, and families work together to repair dams and lodges. Families are very territorial and slap their tails on water as a warning to other Beavers. They also do this to sound an alarm.

Beavers do not have many predators, besides man, but they can be eaten by Red Fox, Coyote, and Otter. Young Beavers are also caught by hawks and owls.

Beavers are extremely important to other wildlife. Their dams create habitat form many species of plants and animals, including: fish, turtles, snakes, frogs, insects, herons, Osprey, eagles, Belted Kingfishers, ducks, geese, otters, Raccoons, and Muskrats.

Wildlife Services Image Collection

Copyright, Noecker Buick Pontiac

When Beavers build a dam, it does many things to the area around it. It makes places of deep and shallow water, which helps fish. The many sticks and branches provide good cover and shelter both above and below the water's surface. Fish, frogs, snakes, turtles, and insects need this. The surface of the dam is a good place for waterfowl, such as ducks and geese, to build nests. It also provides good basking places for turtles and snakes to get warm from the sun.

Birds and other animals that eat fish, frogs, and insects are attracted to dam sites as good places to feed.

When Beavers build a dam, it often changes the course of the water. Places that were not previously covered with water, now are, and this is habitat for water plants, such as lilies, Lizard's Tail, and cattails. Places where water used to be, but is no longer, have great soil for grasses, sedges, and shrubs. This will attract deer, rabbits, and songbirds, as well as many other animals. Eventually, these places will become meadows, and much later, forests.

Beavers also help trees in places where they cut trees down. This might sound strange, but it is true. Beavers have favorite species of trees which they use. When they take them, other trees, which aren't their favorites, are able to grow better without competition. American Elm is a tree that is not usually touched by Beavers. Therefore, Beavers help elms when they cut down competing trees, such as willows and hickories.

Beaver's also create "runways" in marshes by traveling back and forth on the same path. This makes a sort of underwater ditch, which turtles and other animals use make their travel across the marsh easier.

Huntley Meadows Park

Additional Media

Beaver Slapping Tail on Water
Beaver Gnawing on Tree
Beaver Swimming/Walking
Phil Heine
Beavers Eating
Phil Heine
Turtle Using Beaver Runway
Mark Moran
Beaver Coloring Page
Link to Printable Page
Download Quicktime if you are unable to play video

Relationships in Nature:


Bigtooth Aspen

Red Fox

Common Cattail

Creek Chub SP

Tussock Sedge


Black Willow

Largemouth Bass SP

Long-leaf Pondweed

Great Horned Owl

Common Reed

Channel Catfish SP

Flowering Dogwood

Red-tailed Hawk

Lizard's Tail

Yellow Perch SP

Green Algae

Barred Owl

Yellow Pond Lily

Bluegill SP

Cinammon Fern


Canada Goose SP

Common Ragweed

Long-leaf Pondweed

Mallard SP

Witch Hazel

Common Duckweed

Great Blue Heron FP

Black Willow

Tussock Sedge

Belted Kingfisher FP


Cinammon Fern

Bald Eagle FP

American Beech

Poison Ivy

Muskrat SP

Mockernut Hickory

Witch Hazel

Northern Water Snake SP

Red Maple

Red Maple

Common Snapping Turtle SP

Silver Maple

Mockernut Hickory

Raccoon FP

Common Duckweed


Pickerelweed Mu

Green Hawthorn

American Beech

Common Cattail Mu

Virginia Rose

Bracken Fern

American Elm C

Yellow Pond Lily

Spotted Jewelweed

Bullfrog SP

River Birch


Green Darner SP

Bigtooth Aspen

Relationship to Humans:

Humans have a love/hate relationship with Beavers. For many years, Beavers have been hunted and trapped for their fur. They were even eliminated from much of their habitat in America. Today, they are doing much better.

Even so, people get upset with Beavers for the damage they cause to trees and with their dams. If people live near water, and don't want to lose their trees, they often have Beavers trapped or killed. This happened in nearby Washington, D.C. when Beavers were using the famous cherry trees for food.

Dams, since they change the shape and course of water, can cause flooding. People who build their homes too close to water get upset when Beavers build a dam which may flood their property. This is one reason Virginia has passed laws to keep people from building too close to water.

Overall, Beavers are extremely helpful. They provide habitat for so many important animals and plants, and help keep water healthy and clean.


Castor canadensis


Organism Menu
Student Activities
Classification Info
How to Use This Site