The Beaver

The Beaver have returned after a long hiatus!! The guy above is telling his friends that someone’s a bit too close!

At 3-4 feet long (tail included) and 40-60 pounds, the Beaver is the largest rodent in North America. Once among the most widely distributed mammals in North America, beavers were eliminated from much of their range in the late 1800s because of unregulated trapping. With a decline in the demand for beaver pelts and with proper management, they became reestablished in much of their former range and are now common to abundant in their favorite habitat: along rivers and streams, in ponds and lakes…almost any area where adequate year-round water flow exists. In areas where deep, calm water is not available, beavers that have enough material will create impoundments by building dams across streams or other watercourses…the only species (other then human) that can actually create its own habitat! In doing so, beavers provide quality wetland habitat for many dozens of species of birds, mammals, amphibians, invertebrates, and fish…including rare, threatened, and endangered species.
Only humans can alter the environment more than the Beaver. Their dams create habitat for many other animals and plants. Moose use the highly nutritious emergent and submergent aquatic plants found in the deeper beaver flowages. In winter, deer and moose may frequent beaver ponds to forage on shrubby plants that grow where beavers cut down trees for food, dams, or lodges. Deer benefit from lush meadows that develop along flowages when beaver dams no longer hold water. Otters, mink, raccoons, and herons hunt frogs and other prey along the marshy edges of beaver ponds. Waterfowl such as black ducks, wood ducks, hooded mergansers, and green-winged teal are closely tied to these flowages to forage, raise young, and rest during migration. Ducks and geese may even nest on top of beaver lodges, which offer warmth (from the beavers that live below) and protection (especially when lodges are located in the middle of a pond). Trees killed by rising water levels provide perch sites for avian predators, habitat for insects, and food for insect-eating birds such as woodpeckers. These trees also develop cavities that many species of animals require for nesting. In places where beaver dams have been maintained for years, “underwater meadows” form as a result of decades of silt retention; these new landscapes have been shown in a recent study to lessen the effects of climate change by storing carbon in these unique meadows…keeping it from forming greenhouse gasses!!
The beaver’s incisors (front teeth) are harder on the front surface than on the back, and so the back wears faster. This creates a very sharp edge that enables a beaver to easily cut through wood. These teeth grow continually, but get worn down by cutting trees, peeling bark, and feeding. The tail is important both in the water and on land. In the water, the flexible tail acts a four-way rudder. As a danger warning to other beaver and perhaps to frighten perdators, beavers slap their tails against the water, creating a loud splash. Covered with leathery scales and sparse, coarse hairs, it stores fat, and releases body heat, helping with body temperature regulation. On land, the tail helps with sitting or standing upright, and serves as a counterbalance and support when a beaver is walking on its hind legs while carrying building materials with its teeth, front legs, and paws.
Beavers live in large groups called colonies…a parenting couple (who usually mate for life), and a few generations of their offspring. Their lodge where they all live is built near the middle of the pond created by their dam. In the Fall, they coat it with a layer of mud, which freezes and hardens to a protective coat, discouraging predators from digging! They forage and work mostly at night, can swim 5 miles per hour, stay underwater for 15 minutes, and have transparent eyelids which function as goggles…helping them see under the water. Beavers live about 10 years, and up to 24 years, avoiding black bears, coyote, lynx, bobcat, fisher, and dogs, and escaping severe winter weather, winter starvation, disease, water fluctuations, floods, and falling trees. When their food supply decreases, they will abandon their structures and relocate, usually by traveling upstream to a more food-rich area. Their old dams will eventually erode, slowly releasing the impounded water to reveal an extremely rich bottomland for insect-loving, bird-feeding plants to emerge. About 10,000 beaver are killed by trapping in Maine each year.
It is illegal to remove or modify a beaver dam or lodge without permission from a district game warden or regional wildlife biologist….and for very good reasons. Sudden removal of dams can release huge amounts of turbulent flowing water, causing the destruction of property and valuable downstream waterfowl, amphibian, and other animal brood rearing habitat; the sudden release of built-up sedimentation adds to this destruction, impacting the delicate soil ecologies that have evolved through the centuries, and causing the probable local extinction of various plants…upon which many creatures that depend. Efforts are underway in suitable areas to re-introduce these once thriving creatures, whose habitat-creating instincts help to stabilize the surrounding areas by lessening water and soil erosion caused by seasonal heavy water flows, and capturing and treating contaminants in their newly created “bio-recycling mud”!!
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