Beaver (American)

Expert engineers

Beavers are the largest rodents of the northern Hemisphere.

Plant Eating Mammals (Herbivore)
Class: Mammalia (mammal)
Order: Rodentia (rodents)
Family: Castoridae

There was a time when beavers were found all over North America and Europe, but today their range in North America is much smaller and they are all but extinct in Europe. Beavers are largely confined to regions with mixed or coniferous forests near rivers.

Excellent swimmers
The beaver (Castor canadensis) has dark brown long hair. It has a thick body with short, strong legs. A beaver's short head is supported by a powerful, flexible neck. The body length of a beaver is 60-110cm plus a tail of up to 50cm.

The beaver is a superb swimmer. Since it is a water-based animal, its webbed hind feet are used as paddles for swimming. The forefeet are not webbed and the beaver uses them to carry sticks, logs and mud for its lodges and dams and for its varied construction work. It has a remarkable broad, flat and scaly tail which it uses as a rudder in water and a prop on land.

Orange teeth!
Beavers have powerful jaws and chisel-sharp orange coloured incisor teeth which are ideal for biting through tree branches and gnawing at the bark which forms its main diet.

The busy beaver
Beavers have designer homes called 'lodges'. The lodge is built out of intertangled sticks and twigs and plastered with mud. The entrance to a lodge is under water and when the surface of the lake or pond freezes in winter, the entrance is well below the ice. Through the long, harsh winter, beavers remain warm and secure in their lodges, out of reach of prowling wolverine, wolf, lynx, coyotes, bears and other hungry animals which prey on them.

Beavers feed mainly on the inner bark of trees such as birch, aspen, beech, maple and willow. To get to the bark they sometimes fell large trees. Summer offers a great variety of green vegetation to feed on.

Beaver society
Beavers love company and usually live in pairs or groups of 4-8 family members. Though they mark the boundaries of their own territories and lodges with scent from glands, a number of beaver families and their lodges may be found in the same lake. All beaver families work at maintaining the dams and waterways.


Good conservationists!
Beavers chop down trees to create dams to form a pond deep enough not to freeze to the bottom, providing storage for winter food and year-round underwater access to the lodge secure from predators.

A North American beaver's most passionate occupation is building dams and canals. This is because it spends most of its life in the safety of the dam. It creates an artificial lake by damming the flow of a stream and builds its home within the lake.

The dam is a wonder of instinctive structural engineering. Beavers start building a dam in summer when flood waters are at their lowest and continue working until it begins to turn cold.

How are the dams made? First of all, using their razor sharp teeth and extremely flexible hands, beavers bring down trees and shrubs to dam water flow. They then intertwine the branches, and make the dam complete with a final coat of mud and dead leaves!

Beavers may seem destructive because they chop down trees for food and building material, but in fact, they actually help preserve the forest in the long run. A beaver-made lake may eventually silt up, providing rich soil for meadows and trees. Beaver dams also help control spring floods and create marshy wetland areas in which other wildlife thrives. These dams are used by many beaver generations.

Bringing up babies!
Usually, about 3-4 baby beavers called 'kits' are born in April or May. While the mother suckles the kits, the males live by the lakeshore in a burrow.

Soon, the training of the kits begins. The mother teaches them which plants to eat and which trees to fell for building dams. Baby beavers live with their parents for 2 years or more, until they are actually driven out! Then they may travel a long way in search of a suitable site to build their own house.


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