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Despite its name, the mountain beaver is not actually a beaver, although it is classified as a rodent. It can be found it the westernmost parts of North America, particularly in the wetter forests. Instead of building dams, like real beavers, the mountain beaver digs elaborate tunnel systems underground. Some scientists believe that it is the oldest type of rodent in the world.
Known scientifically as Aplodontia rufa, the mountain beaver is the only member of the Apolodontiidae family. Some people also refer to this rodent as a giant mole or ground bear. It is also sometimes referred to as a Sewellel beaver, after a type of cloak that a Native American tribe made from its pelt.
The mountain beaver is not related to the North American or Eurasian beaver. In fact, it's not even a beaver at all. This rodent gets its name from the way it chews and removes bark and limbs from trees.
Mountain beavers are roughly the same size as a muskrat. An adult mountain beaver will usually grow to be about 1 or 2 feet (30.5 or 61 centimeters) long, from nose to tail. It typically has a very short tail, which rarely grows longer than 1.5 inches (3.8 centimeters). It's fur is usually brown to reddish brown in color, depending on the subspecies.
Lewis and Clark first described this animal during their travels to the western part of North America. Today, this large rodent can be found primarily west of the Cascade Mountains. It can be found from the northern part of the state of California and north to British Columbia, in Canada.
The mountain beaver does not just live in the mountains. It is often found in the damp forests of this region. Although it will inhabit deciduous forests, it generally prefers areas with coniferous trees.
One of the most common signs of a mountain beaver are the entrances to underground burrows. There may be several entrances to this elaborate underground tunnel system, and they are usually around six inches (15.2 centimeters) in diameter. These tunnels also usually contain several chambers to store food and hard pieces of feces.
Many scientists believe that the mountain beaver is the oldest living rodent today. Some even refer to it as a living fossil because its body is so primitive. For instance, this rodent's kidneys are much less sophisticated than those of modern animals. They are unable to completely process the animal's uric acid, so mountain beavers must drink more water than other animals. This is why they are typically found it wet climates with heavy rainfall.