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Mountain Beaver Aplodontia rufa


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Mountain Beaver
credit: Gary M. Feller

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Family: Aplodontidae, Mountain Beavers view all from this family

Description An odd, medium-sized burrowing rodent with small eyes and ears and long whiskers and claws. The fur is dark brown, and there is a pale spot below each ear. Somewhat resembles a giant pocket gopher. The tail is short and furred and head has a distinctive triangular, flattened skull with high, conical cheek teeth.

Dimensions 24-47cm, 19-55cm, 0.8-1.2kg

Endangered Status The Point Arena Mountain Beaver, a subspecies of the Mountain Beaver, is on the U.S. Endangered Species List. It is classified as endangered in California. As with so many other animals, the mountain beaver's endangered status followed the degradation of its habitat. The usual culprits can be named, including development, livestock grazing, and logging. Because the remaining populations are isolated and small, threats such as predation by other animals (including pets), poisoning, trapping, and other disturbances, can have a significant affect on the overall numbers, as an entire population can be exterminated quite easily.

Breeding After mating early in the year, a single litter of 2 or 3 is born in the spring after a gestation period of about a month. The young remain in the natal burrow throughout the summer, although lactation lasts only about 2 months. The young then disperse in the fall, and establish burrows of their own.

Habitat Lakes, ponds, rivers & streams, Forests & woodlands

Range Southwest, California, Northwest, Western Canada

Discussion Also known as Sewellel. Thought to be the most primitive rodent species and placed in its own family. Although it rarely ventures far from its 15cm burrow entrance, it can climb trees in search of food. Strictly vegetarian, it is known for eating plants such as rhododendron and stinging nettle that other animals typically avoid. Extensive burrow systems include a toilet chamber. Typically remains underground in winter, eating cached foods. They are coprophagous, reingesting soft fecal pellets to maximize nutritional value from stored food items. The sole member of the rodent family Aplodontiidae. Also called mountain beavers, but they are neither montane nor aquatic. Nocturnal and secretive, and essentially solitary. Maximum lifespan is about 6 years. Endangered in California. Spends most of its life in underground burrows dug into the soil of moist forests with densely vegetated understories.