The ranger tells us the beaver has built a lodge and that he controls the water level in the area with his dams. He said the beaver mostly eats the roots of cattails, but also feeds on the bark of cottonwood, willow and salt cedar. He has observed the animal digging channels perpendicular to the river bed in preparation for a big rain. When rising water flows into the channels the beaver works quickly to dam the entrances, creating new pools at the high water mark.
A beaver family consists of a mated pair and various children. The kits may stay on with the parents for up to two years. They too stay busy, helping cache food and repair dams and caring for younger kits in between bouts of play. A beaver keeps growing its whole life, so they can get big, up to 60 pounds. A young adult weighs about 30 pounds and is two feet long. The luxurious beaver pelt is famous, as is the tail. Broad, flat and covered with scales, it makes an impressive boom when slapped on the surface of the water. This alarm sends all of the beavers within earshot, above and below water, swimming for safety.
Beavers are strongly territorial and the center of their world is the dam. One large tree is usually felled to create a shallow pond. Smaller trees and branches may be piled around the fallen log or elsewhere in the area, to form a lodge partly below and partly above water. This is both home and pantry, as the wood used for construction will eventually become dinner. The industrious rodents work at night, swimming with branches in their teeth, or hurrying along the riverbank carrying mud and stones in their front paws. Beavers may also raise their young in grass lined dens dug into banks, well above the waterline. The perimeter of the beaver’s territory is marked profusely with scent markers to warn other beavers off.
The rolled cement dykes spanning the riverbed below the Liberty Wildlife site were built decades ago to slow and reduce the power of rapidly moving flood waters. In the same way, a population of beavers on the river modulates water flow. Urban beavers have made a home in the Bronx River in New York City and at Lincoln Park in Chicago. An entire habitat restoration project was born when a San Francisco suburban community came together to protect the beaver in their river. And, on a perennial reach of water on the Salt River in Phoenix, the beaver makes a welcome addition to a rich population of wildlife.
Photo credits for this story: Wikipedia Commons