Small Mammals

Several species of shrews, voles, mice, and lemmings have been documented on Togiak National Wildlife Refuge, including the rare Alaska tiny shrew.

  • Brown Lemming (Lemmus trimucronatus)

     The brown lemming is the most widespread of Alaska's true lemmings. Brown lemmings are tawny or reddish-colored year-round, although they may turn more grayish in summer. They are a thick-set rodent with long fur, small ears and a short hairy tail. Brown lemmings weigh between 2 and 4 ounces and reach around five inches in length; their tail adds another two-thirds of an inch.

    Brown lemmings feed primarily on grasses, sedges, seeds, willow bark and insects. They inhabit tundra and alpine meadows. Lemmings remain active year round and create tiny trails beneath the snow moving to and from their nests in the winter. Their populations fluctuate dramatically, which gives them a reputation for suicidal migrations that is more fiction than fact. Lemmings do not migrate, but in times of stress, individuals may move to the edges of their habitat. This may explain their presence on sea ice and other inappropriate habitat. 

  • Meadow Jumping Mouse (Zapus hudsonius)

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     The coat of this mouse is dark above, yellow on the sides, and white underneath. This is a medium-sized mouse that has short forelegs, lengthened hind legs, and a long tapering tail. Meadow jumping mice average around 8 inches long including a 5 inch tail. Jumping mice are reported to be capable of jumping more than 3 feet in a single bound.

    Jumping mice feed on vegetation, seeds, nuts, grains, fungus, berries, fruit, and insects. They occupy forests and moist plains where they are usually found in brush and shrub lined streams. Summer nests are made in shallow burrows, but hibernating nests may be three feet or more below the ground.

  • Northern Red-Backed Vole (Clethrionomys rutilus)

     Northern red-backed voles (also called tundra voles, but not to be confused with true tundra voles, below) usually have a broad reddish stripe down their back and tan-red sides. These small to medium-sized voles have small eyes, and small ears reaching just above their fur. Their average total length is 5.5 inches, including their 1.5 inch tail. They can be distinguished from meadow mice by their conspicuous reddish back.

    This species is omnivorous, eating mainly greens, berries, seeds, lichens, fungi and insects. Red-backed voles are found mostly in cool, damp locations in forests or on the tundra. Northern red-backed voles are active year-round and do not hibernate. 

  • Tundra Vole (Microtus oeconomus)

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     Tundra voles average 8 inches long including a two-inch tail. They have a fairly uniform color, and this, along with their larger size, helps distinguish them from most other small rodents in Alaska.

    Tundra voles prefer moist to wet tundra. They make runways through the tundra vegetation and nest in shallow burrows. Tundra voles feed on grasses, sedges, seeds, grain, bark, and insects.

  • Meadow Vole (Microtus pennsylvanicus)

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    This is the most widely distributed species of vole. The Meadow vole varies from a gray washed with brown to dark brown. The belly is silvery or dark gray and the tail is bicolored. Meadow voles average around 7 inches long including a 2 inch tail.

    Meadow voles make their homes in low moist areas or high grasslands. They feed on grasses, sedges, seeds, grains, bark, and insects. Meadow vole nests can be found either above or below ground.

  • Common Shrew (Sorex cinereus)

     All shrews have short legs, a long, pointed snout, and long whiskers. The common shrew (or masked shrew) has a grayish-brown body, a bicolored tail, and pale underparts. They average 2 inches in length, with an additional 2 inch tail.

    Masked shrews occupy moist habitats in forests, open country, and brushlands. To meet their high energy requirements, they must eat more than their own weight each day. Masked shrews mainly feed on insects but will also prey upon other small animals.

  • Pygmy Shrew (Sorex hoyi)

     Pygmy shrews are slightly smaller than Common shrews, but can only be distinguished for certain by their teeth. By weight, the Pygmy shrew is the smallest living mammal, weighing about as much as a dime. They average 2 inches in length and have an additional inch of tail. Pygmy shrews occupy wooded and open areas, either wet or dry. They feed on the same items as other shrews, mostly insects.

  • Arctic Shrew (Sorex arcticus tundrensis)

     The Arctic (or tundra) shrew is the most brilliantly colored of the shrews. Its back, sides, and belly all contrast. In winter, they are tricolored with a nearly black back, and in summer their coat is a dull brown. Arctic shrews average 3 inches long and have an additional one-inch tail. Arctic shrews occupy spruce swamps, chiefly preying on insects and other invertebrates.

  • Alaska Tiny Shrew (Sorex yukonicus)

     Alaska tiny shrews average 45 to 48 millimeters in length, with an additional 23 mm of tail. Their fur is slightly tricolored grey and the tail is bicolored with white on the sides.

    A new species first described in 1997, a specimen collected from the Togiak National Wildlife Refuge in 1996 is one of only 10 known. The discovery of one of these Alaska tiny shrews on Togiak Refuge documented a significant range extension for this animal. Seven of the ten known specimens were collected in riparian habitats.

    Visit the University of Alaska's museum collection to learn more about this rare species.

  • Resources

    Burt, William H. and Richard P. Grossenheider. 1980. Peterson field guide to mammals. Houghton Mifflin Company. Boston Massachusetts.

    Alaska Geographic Society. 1996. Mammals of Alaska: a comprehensive field guide from the publishers of Alaska geographic. The Alaska Geographic Society. Anchorage Alaska.