Species Guide: Eurasian Beaver (Castor fiber)1
Family: Castoridae
APPEARANCE
The Eurasian Beaver is a semi-aquatic rodent. Significantly, Beavers are the second-largest rodent on the planet, the largest being the Capybara. They have large, stout-looking bodies covered in brown fur, webbed feet, and a broad tail, plus, they also have prominent orange-colored teeth. There are only two living species of Beaver in the world, namely the Eurasian Beaver (scientific name Castor fiber) and the North American Beaver (scientific name Castor canadensis).
Diet
Contrary to many urban legends, the Eurasian Beaver doesn’t eat fish, they are herbivores, with a diet made up of aquatic plants, grasses, as well as the bark and leaves of trees.
HABITAT
Originally extinct as a species in the UK some 500 years ago, re-introduction programs have been successful. Consequently, Beavers have established themselves in the wild in Tayside, Argyll, and Devon. Other reintroduction programs have been performed in the UK but are within fenced enclosures.
Beavers need water within their habitat as a primary requirement. It doesn’t matter whether, for example, it’s a stream, river, or loch, provided there is a constant supply, and sufficient space to allow them to swim, build lodges, and protect their burrow entrances. Beavers need a source of food but are quite flexible given that they eat a variety of vegetation. They thrive if their environment includes woody vegetation such as trees and shrubs. Otherwise they are limited to living in the holes in banks. Wooded vegetation is also preferable within a few meters from their water source. Beavers are vulnerable on the land and prefer to be close to their source of water so that they can escape.
Note that this map is for a rough illustration of animal distribution across the UK, whereby light green indicates established wild populations. Other populations of Beavers exist in the UK but are enclosed within fenced areas. These have been excluded from the map since they are technically caged as opposed to wild populations.
Behavior
Beavers are synonymous with their ability to build damns to create areas of still water; where they can then build lodges in which to live. Beavers have huge teeth and will gradually coppice trees to construct their lodges, noting that it’s these very behaviors that place Beavers at odds with farmers, who see the activity as degrading their agricultural land. On the other hand, it is also demonstrated that Beavers help control the flow of water, and provide a rich habitat for birds, insects, amphibians, and bats.
Beaver lodges are constructed from branches and sticks, held together with mud; which also helps to insulate them from the elements. They will often construct the lodge with a chimney so that they can regulate the inside temperature.
They are thought to mate for life and live in family groups with youngsters staying with their parents for around two years before leaving to find their own territories. Beavers have between two and four young each year, called kits.
Did You Know? Beavers are powerful swimmers and can stay underwater for up to 15 minutes. They have transparent inner eyelids to help them see when in the water, and their nose and ears can shut to keep water out.
Biometrics
| Body Length | 1 m |
| Body Weight | 19 kg |
| Longevity | 8-25 Years |
NATURAL PREDATORS
Beavers tend not to travel far from the safety of their lodges which are pretty impenetrable. Consequently, they have no natural predators in the UK. Wolves and Lynx are known to be a threat to the Beaver in Mainland Europe and the US. Here is a quote from the famous Naturalist Enos Mills, which paints a vivid picture of how impenetrable a Beaver lodge is.
“I came upon a beaver house that was surrounded by a pack of wolves. These beasts were trying to break into the house. An early autumn snow had blanketed the house and thus prevented its walls from freezing. The soft condition of the walls, along with the extreme hunger of the wolves, led to this assault. Two of these animals were near the top of the house clawing away at a rapid rate. Now and then one of the sticks or poles in the house wall was encountered, and at this, the wolf would bite and tear furiously. A number of wolves lay about expectant; a few sat up eagerly on haunches, while others moved about snarling, driving the others off a few yards, to be in turn driven off themselves”.2
Conservation Status
U.K.
Conservation Status
Global
Conservation Status
