Not much is known about this shrew, but it may be widely distributed in the Great Basin, Columbia Plateau, northern Great Plains, and southern Rocky Mountains.
Merriam's shrew is brownish-gray or gray above which whitish undersides. Its tail is distinctly bi-colored. It is smaller than the dusky and masked shrew and it is very difficult to identify. Only close, microscopic examination of the teeth will allow experts to identify it with certainty. Its total length is 3.5 to 4.3 inches (88 to 107 mm), tail length is 1.3 to 1.7 inches (33 to 42 mm) and it weighs 0.14 to 0.24 ounce (4 to 7 grams).
It is found at elevations of 200-2900 m, primarily in grasses in shrub steppe or pinyon-juniper habitat (recorded in spruce-aspen grove in New Mexico). Seems to prefer drier habitat than other shrews. In Idaho, this species has only been collected in sagebrush habitats, but it is also known to occur in mountain mahogany.
Feeds primarily on insects and other small invertebrates. Caterpillars are most common summer food item.
It is active throughout the year and it may utilize burrows and runways of other animals. In Washington and Wyoming, frequently found in association with sagebrush voles. Owls are only known predators. Displays summer and winter pelage. Recent studies in Idaho suggest species is more common than previously thought.
In Washington, pregnant females have been captured from mid-March to early July; litter size produced by 3 females ranged from 5 to 7 young. Males develop large flank glands in the spring, which may be an attraction for females. These flank glands may also repel predators.
|Status:||Unprotected nongame species|
Important State References:
Mullican, T.R. 1986. Additional records of Sorex merriami from Idaho. Murrelet 67:19-20.