Beavers are large mammals from group of rodents. Remarkable feature of these animals — their ability to construction. Beavers, except holes and floating dwellings, build platinum, partitioning off courses of streams and the rivers.
The family beaver is presented by the only sort — beavers in which only two views - an ordinary beaver and the Canadian beaver. Both views have similar habits, appearance, the habitat. A difference only that the ordinary beaver inhabits the Eurasian continent, and Canadian — North America.
Earlier was considered that the Canadian beaver only subspecies of a beaver ordinary. However later researches showed that they have a retail in number of chromosomes — at an ordinary beaver — 48, at Canadian — 40.
The beaver one of the biggest rodents on the planet after a capybara, in Eurasia — the largest — its length hesitates between 90 and 130 cm, the Canadian beaver is a little less. The weight of an animal reaches 35 kg.
The body of a beaver extended, is covered dense dark brown, sometimes with black fur. Beavers are good swimmers, on the land they much less dexterous. Membranes between fingers and a long flat tail help them to move with water.
One more interesting device for water life at a beaver is isolation of cutters from other mouth that allows an animal to gnaw under water, without being afraid to choke.
Dwellings of beaversBeavers lodge on coast of reservoirs with dense vegetation on coast, spending the most part of time in water. Dwellings of beavers happen two types: the holes and constructions called by hatka. Beavers dig holes in steep coast. Usually it is the central inhabited camera and an extensive network of the courses terminating in several exits. It is remarkable that an exit will always be organized under water for protection of the dwelling against predators. Hatki are under construction where digging of holes is impossible — on the marshy soil, low coast or shallows. Hatka represents a conic brushwood with a diameter of basis up to ten meters structure, in height - to three. Walls of a hatka become stronger clay. In a hatka there is a room over the level of water and several exits. Air comes to such dwelling through a small opening in a ceiling. Entrances as well as in a hole, take place under water. Thus, quite deep reservoir is necessary for beavers for protection of dwellings. If depth of a stream or the river is not enough, animals construct dams.
PlatinumFor maintenance of water level in the beaver town the rodents build dams. As construction material serve trunks of trees, brushwood, sometimes stones. The design is fastened with silt and clay. From one edge of platinum arrange a drain.
The record on the extent of a dam belongs to the Canadian beaver. In the north of the USA in the State of New Hampshire the dam more than 1200 meters long is found.
The usual size of platinum is 20-30 meters in length. Width in the basis of 4-6 meters, in the top part — 1-2 meters. Design height, as a rule, about two meters. Beavers watch closely the built dam. In case of damages, animals repair a construction as safety of all settlement depends on it.