North American Beaver (Castor canadensis)


Class: Mammalia
Order: Rodentia
Family:    Castoridae
Size:    Length: 3 to 4 feet (9 to 12 m)
Weight: 30 to 70 pounds (20 to 27 kg)
Diet: Bark, buds and roots
Distribution: Most of Canada and the U.S. except for most of Florida, Nevada and California
Young:  2 to 4 kits, once per year
Animal Predators:  Wolves, coyotes, otters, foxes, black bears and bobcats
IUCN Status: No special status
Terms: Young: Kit
Lifespan: Up to 24 years in the wild and 35 to 50 years in captivity



·         Beavers are monogamous and pair for life.

·         Canada’s national animal, the beaver appears on the Canadian nickel.

·         The scientific name means: Castor—beaver; canadensis—of Canada.

·         Beavers can walk on their two hind feet, carrying sticks with their forelimbs.

·         Beavers can cut through a tree with their teeth at the same rate as a power saw.

·         Beavers live in harmony with each other and are tolerant of other animals such as muskrats.

·         Beavers cry when they are frightened. 



North American beavers have shiny, reddish-brown fur that is waterproof. Their back legs are extremely powerful and their feet are webbed, enabling them to swim quickly. They can close their noses and ears while swimming underwater, and have clear eyelids that they close when swimming to protect their eyes while still being able to see where they are going. Their tail is flat, and resembles a canoe paddle. 



Beavers build their dams in streams and lakes. Within the dammed area they build a dome-shaped lodge where a male and female live with their offspring from previous seasons and their new kits. 


Feeding Habits

Beavers eat tree bark in the same fashion humans eat corn on the cob, and then use the remaining tree for their homes.



Litters of kits (usually two to four, but possibly as high as eight) are born in late spring with full coats of fur. The kits are not weaned until up to two months after they are born. Although all the family members gather food for the youngsters, the father will take on most of that responsibility. While swimming with their parents, the tiny kits will at times fall behind—the parents then stop and wait for them to catch up, allowing the kits to hang onto their parents’ tails or fur with their teeth or ride on their parents’ backs. The kits and their parents play together in the water, swimming around each other, leaping out of the water, and rolling over and over. When danger is present, the male swims back and forth to get the attention of the potential predator, slapping his tail on the water in warning, while the others escape before disappearing under the water’s surface at the last moment. The young usually remain with their parents for two years, then head out to find their own territories and start their own families.



In groups of two or more, beavers find and cut down trees to use for their dams and lodges. When a dam needs to be rebuilt or fixed, the entire family helps by bringing sticks and placing them in it. The entrance to the lodge is near the stream bottom to keep out potential predators. They are semi-aquatic animals and can stay underwater for up to fifteen minutes before. They are primarily nocturnal, but can be seen in the afternoon in areas where there is minimal human intervention. 



Beavers once lived in practically every area in North America, but overhunting by humans caused numbers to decline almost to the point of extinction. Regulations were enforced in the 1950s to protect beavers. The wetlands created by beavers provide homes for many other animals, and their dams control erosion, as well as reduce the amount of silt introduced into large rivers. 



North American Beaver Wildlife Fact File, IM Pub, US