American Beaver

American Beaver

North American beaver, Canadian beaver

Castor canadensis
Population size
Life Span
10-20 years
Top speed
km/h mph 
kg lbs 
cm inch 

The North American beaver (Castor canadensis) is a semiaquatic animal native to North America. It is one of the official national wildlife of Canada symbols and is the official state mammal of Oregon and New York.


The fur of this animal consists of long, coarse outer hairs and short, fine inner hairs (see Double coat). The fur has a range of colors but usually is dark brown. Scent glands under the tail secrete an oily substance known as castoreum, which the beaver uses to waterproof its fur. There is also another set of oil glands producing unique chemical identifiers in the form of waxy esters and fatty acids. The lush, workable fur was made into a number of products, most notably hats. The beaver has many traits suited to the semiaquatic lifestyle. It has a large, flat, paddle-shaped tail and large, webbed hind feet. The unwebbed front paws are smaller, with claws. The forepaws are highly dextrous and are used both for digging and folding individual leaves into their mouth and to rotate small, pencil-sized stems as they gnaw off the bark. The eyes are covered by a nictitating membrane which allows the beaver to see underwater. The nostrils and ears are sealed while submerged. Their lips can be closed behind their front teeth so that they can continue to gnaw underwater. A thick layer of fat under its skin insulates the beaver from its cold water environment.




Before their near-extirpation by trapping in North America, these animals lived from south of the arctic tundra to the deserts of northern Mexico, and from the Atlantic to the Pacific Oceans. They are widely distributed in boreal and temperate ecoregions, where populations are rebounding from historic over-exploitation. Recently, American beavers have been observed colonizing arctic tundra, likely as a result of climate-induced increases in riparian shrubs.

American  Beaver habitat map

Climate zones

American  Beaver habitat map
American Beaver
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Habits and Lifestyle

American beavers are highly sociable animals. They make up colonies - family groups of about 8 individuals in each one – and live within a hierarchy. Beavers are very territorial, protecting their home range from other beaver colonies. The period of their highest activity is the nighttime, though sometimes they can be seen in the daytime, more frequently in the twilight. In search of food, beavers are ready to pass long distances. When the source of food is found, a beaver opens water canals to it in order to transport the food across the water to its lodge. Beavers also pile up branches and sticks under the water as winter supplies. In areas of fast water flow beavers construct dams to slow down the stream. Their lodges are very firm to be able to serve as shelters. Beavers construct dams, depending on the speed of the water stream: if the stream is strong, dams are built in a way so as to withstand the pressure of water flow and not be washed away.

Group name
Seasonal behavior

Diet and Nutrition

American beavers are herbivores and lignivores. They feed on the bark of trees and cambium - the inner layer, which is under the bark. The favorite trees include willows, aspen trees, alders, maples, and birches. Along with these, beavers feed upon aquatic plants meanwhile not missing roots and buds.

Mating Habits

January-March in the north, in November-December in southern regions
3 months
3-6 kits
14-90 days
kit, pup

American beavers are monogamous, meaning that they mate once in a lifetime. A lodge serves as a home for a family - a couple and their young (until reaching the age of 1 year). The mating period takes place during winter (January-March) in the north and in late autumn (November-December) - in southern regions. Gestation lasts 3 months, after which 3-6 babies are born. The young are born with dense coat and open eyes. They begin swimming on the very first day of their lives. A few days later their parents take the babies to travel around the home range and explore the world. As a general rule, the young are weaned no later than 2 weeks while sometimes it can take up to 3 months. Parents look after them until they are at least 2 years old after which young leave. Both males and females of American beaver become reproductively mature at 3 years of age.


Population threats

Beavers attract hunters for their pelts. On the other hand, near human settlements, beavers are killed for building dams and destroying trees, thus disturbing human life. In addition, beavers are susceptible to tularemia – an animal disease, common in North America. And finally, a human disturbance may put beavers in real danger: people kill them for pelts and persecute them from their habitat, not speaking about pollution, which promotes wound infection.

Population number

The IUCN Red List and other sources don’t provide the number of the American beaver total population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.

Ecological niche

The American beaver lives in marshy areas which slow down water streams in a case of a flood. The beaver hinders soil erosion and promotes water level rise. Sludge occurs upstream of the dikes thus putting toxins out of action. Ponds start to grow from water, supported by dams, after which lilies appear. And then, when the lodges are left by beavers, eventually the dams start decaying, giving way to meadows.

Fun Facts for Kids

  • Teeth of beavers never stop growing, so they gnaw on trees in order to prevent teeth from becoming too long.
  • Beavers use their tails for swimming as well as flapping the water in order to scare predators away.
  • Beavers have transparent eyelids, serving as underwater glasses and helping them see clearly under the water.
  • Beavers withstand cold temperatures easily. Moreover, they are active during the cold season and even manage to maintain order in ponds around their lodges.
  • Regular lodges of beavers have 2 dens: the first one is to dry off after coming out of water; the second one, a dryer den, is used for beavers’ families to spend their time.
  • Cases are known when beavers’ and muskrats’ families share one lodge together!

Coloring Pages


1. American Beaver Wikipedia article -
2. American Beaver on The IUCN Red List site -

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