Beavers are semi-aquatic rodents native to North America and Europe. They are the only living members of the family Castoridae. Genetic research has shown the European and North American beaver populations to be distinct species and that hybridization is unlikely.
Beavers are best known for their natural trait of building dams in rivers and streams. They build their homes in the eventual artificial pond. They are the second largest rodents in the world.
Beavers continue to grow throughout life. Adult specimens weighing over 55 lb (25 kg) are not uncommon. Females are as large as or larger than males of the same age, which is uncommon among mammals.
The European Beaver was hunted almost to extinction in Europe. However, the beaver is now being re-introduced throughout Europe
The extinct North American Giant beaver (Castoroides ohioensis) was one of largest rodents that ever evolved. It disappeared, with other large mammals.
The habit of the beaver for hundreds of thousands of years in the Northern Hemisphere has been to keep these watery systems. The beaver works as a keystone species in an ecosystem by creating wetlands that are utilized by many other species. Next to humans, no other in existence animal does more to shape its landscape. Beavers have flooded thousands of acres of land and are considered an unstoppable plague.
The dams are created both as a protection against predators, such as coyotes, wolves and bears. They provide easy access to food during winter. It is both the sound of water in motion and the current that stimulates the beavers to build large cage-like filter. They may repair any damage to the dam and build it higher as long as the sound continues. In times of high water, they often allow spillways in the dam to flow freely. Beavers have even attempted to build dams in response to recordings of water flowing, even in the absence of water.
When heavy rains occur, the dam fills up and gradually releases the extra stored water. Often this is all that is necessary to reduce the height of the flood wave moving down the river. This will reduce or eliminate damage to human structures. But flood control is achieved in other ways as well. The surface of a stream intersects the surrounding water table. By raising the level of a stream in a certain area, the gradient of the surface of the water table is reduced. The water by the beaver dam flows more slowly into the stream. This effect not only helps to reduce flood waves but also increases the water flow when there is no rain. The other way beaver dams smooth out water flow is by increasing the wetted area of the stream. This allows more water to seep into the underlying ground where its flow is slowed down. This water eventually finds its way back to the stream.
The ponds are created by well-kept dams, which help isolate the beavers’ home. This is created from severed branches and mud. The lodge has underwater entrances to make entry nearly impossible for any other animal. A very small amount of the lodge is actually used as a living area. Contrary to popular belief, beavers actually dig out their den with an underwater entrance after they finish building the dam and lodge structure. There are typically two dens within the lodge. There is one for drying off after exiting the water. The drier one is where the family actually lives.
When startled or frightened, a swimming beaver will rapidly dive while forcefully slapping the water with its broad tail. This creates a loud ‘slap’, over large distances above and below water. This noise serves as a warning to other beavers in the area. Once a beaver has made this danger signal, all nearby beavers will dive and may not reemerge for some time.