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Western Harvest Mouse Reithrodontomys megalotis


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Western Harvest Mouse
credit: C. Michael Hogan

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Family: Muridae, Mice and Rats view all from this family

Description Small mouse with a relatively long, bicolored tail. Fur is bristly and relatively short. Feet are whitish. The ears are comparatively small and buff to reddish brown. The tail is about as long as the head and body and distinctly bicolored, with relatively long hairs that tend to obscure the scales. Juveniles are grayish brown; subadults are brighter than juveniles but duller than adults. The thick winter pelage is paler and the tail is more distinctly bicolored. Some animals east of the Mississippi River and in the San Francisco Bay area have a buff pectoral spot.

Dimensions 118-170mm, 50-96mm, 8-15g

Similar Species Larger than Plains Harvest Mouse, with longer hair and a more distinctly bicolored tail. Larger than Eastern Harvest Mouse, with a relatively longer tail. Has a less pointed, more bicolored tail than Salt-marsh Harvest Mouse.

Breeding Makes spherical nest of grasses and other plant fibers, lined with softer material, with an opening near the bottom. These are often on the ground, but may be up in the shrubs, or sometimes even underground in the burrows of other animals.

Habitat Beaches, shorelines & estuaries, Deserts, Meadows & fields, Grasslands & prairies, Forests & woodlands, Alpine & subalpine habitats

Range Plains, Great Lakes, Rocky Mountains, Southeast, Southwest, Texas, California, Northwest, Western Canada

Discussion Feeds on herbs, seeds, and insects, including ground beetles when available. They can climb in the shrubbery to reach flowers and seeds. Although they do not make food caches, they do lay down body fat in the fall. They do not hibernate, but can become torpid for short periods, relying on fat stores to get them through periods of extreme weather. This species is very widespread and tolerant of a wide range of habitats, ranging from arid deserts and sand dunes through fallow fields, woodland clearings, and disturbed habitats such as roadsides and fence rows from sea level to 4000m.