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What Is a Mountain Beaver?

Christina Edwards
Christina Edwards

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 prefer to live in forests of coniferous trees.
Mountain beavers prefer to live in forests of coniferous 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.

Frequently Asked Questions

What is a mountain beaver and where can it be found?

The mountain beaver, scientifically known as Aplodontia rufa, is a primitive rodent native to the Pacific Northwest of North America. Despite its name, it is not a true beaver but rather the sole living member of the family Aplodontiidae. These creatures inhabit moist forests and dense brush areas, often near water sources.

How does the mountain beaver differ from the common beaver?

Mountain beavers are smaller than common beavers, with a stockier build, and lack the flat tail associated with their aquatic namesakes. They do not build dams or lodges but instead dig extensive burrow systems. Mountain beavers are also more solitary and less adapted to aquatic environments compared to the semi-aquatic common beaver.

What do mountain beavers eat?

Mountain beavers are herbivores with a diet consisting mainly of ferns, leaves, and shoots. They have a preference for succulent plants and have been known to cause significant damage to reforestation efforts by eating young tree seedlings, which can have economic impacts on the timber industry.

Are mountain beavers endangered?

Mountain beavers are not currently listed as endangered; however, their populations are affected by habitat destruction and fragmentation. Conservation efforts focus on preserving their natural habitats and understanding their ecological role. Localized populations may be at risk, emphasizing the need for ongoing monitoring and habitat protection.

What unique characteristics do mountain beavers have?

Mountain beavers have several unique traits, including a specialized digestive system with a large cecum that allows them to digest tough plant material. They also have poor thermoregulation, which requires them to live in cool, damp environments. Additionally, they are among the most primitive living rodents, with evolutionary roots dating back 40 million years.

How do mountain beavers reproduce and raise their young?

Mountain beavers typically breed once a year, with a gestation period of about a month. Females give birth to one to four young, which are weaned after several weeks but may stay with the mother for up to a year. The young are born well-developed compared to other rodents, with fur and open eyes.

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    • Mountain beavers prefer to live in forests of coniferous trees.
      By: Sergey Belov
      Mountain beavers prefer to live in forests of coniferous trees.