American beaver is aquatic animal. Its coat is repellent with shiny, rich, blackish-brown to russet color. The under layer of hair is tighter and more protective, than outer layer. Ears usually have umber color, being round and short. Skull and teeth of American beaver are quite large for its size. When a beaver walks, front part of its body is closer to the ground than rear, due to its front legs being shorter than hind legs.
Close proximity of water is the topmost life condition for American beaver. It prefers living near lakes, rivers, ponds and rills. It’s a native North American animal, found, along with its native land, in Argentina, Belgium, Finland, Germany, Luxembourg, Russia.
American beaver is highly sociable animal. Beavers 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. Period of their highest activity is the nighttime, though sometimes they can be seen in the daytime, more frequently in 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 food across the water to its lodge. Beavers also pile up branches and sticks under the water as winter supply. 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 speed of water stream: if the stream is strong, dams are built in a way so as to withstand pressure of water flow and not be washed away.
American beaver are herbivores (lignivores), they feeds on bark of trees and cambium - the inner layer, which is under the bark. Favorite trees of American beaver are: willows, aspen trees, alders, maples and birches. Along with these, beaver feeds upon aquatic plants meanwhile not missing roots and buds. Normally, mammals can’t digest cellulose whereas it proves to be an important component of beavers’ everyday ration. You can see beavers in the zoos, being fed by so-called ‘rodent food’ as well as potatoes, lettuce and carrots.
American beaver is monogamous, meaning that it mates once in a lifetime. A lodge serves as home for a family - a couple and their young (until reaching the age of 1 year). 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 babies are born with dense coat and open eyes. They begin swimming during 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, babies 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 reach maturity at 3 years of age.
Beavers attract hunters for their pelts. On the other hand, near to human settlements, beavers are killed for building dams and destroying trees, thus disturbing human life. In addition, beavers are susceptible to tularemia – animal disease, common in North America. And finally, human disturbance may put beavers into real danger: people kill them for pelts and persecute them from their habitat, not speaking about pollution, which promotes wound infection.
Although the population number is not known, one thing is certain: presently, the American beaver is not endangered. The ICUN classifies this species as "Least Concern". Probably, beavers’ population counts a huge number, based on the fact that they are present all around the habitat and widespread in North America. Due to breeding rapidly, their population doesn’t decrease. In 1946, for example, 25 pairs of American beaver were brought to one of Tierra del Fuego islands (Chile). As a result, currently there are around 35.000-50.000 individuals of American beaver on the island.
American beaver lives in marshy areas which slow down water streams in a case of flood. The beaver hinders soil erosion and promotes water level rising. Sludge occurs upstream 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.