Preble's shrew (Sorex preblei)

Physical description

Oregon Department of Fish and Wildlife describes Preble’s shrew as follows: …{A]dults commonly weigh less than a dime. The pelage (fur) is medium dark-brown to very dark-gray on the dorsum (topside) and silvery gray on the ventral (underside). The tail is bicolored, medium dark-brown on the dorsal surface, which on the ventral surface and darkening toward the tip.

Ecology and life history

Preble’s shrews are most often associated with sagebrush and grasses but have been collected in a wide variety of habitats, including subalpine shrubland, whitebark pine, and wetlands. In Washington, Preble’s shrews have been captured in dense lodgepole pine, dense subalpine fir/lodgepole, and grand fir/Engelmann spruce forest at 5,000 to 6,000 feet in the Blue Mountains, which is rather atypical habitat for the species. It was also captured in a U.S. Department of Agriculture - Conservation Reserve Program grassland.

Preble’s shrew is an insectivore; mandible morphology suggests a diet of soft-bodied invertebrates, such as spiders and grubs.

Litter size is estimated to be three to six young.

Shrews are active throughout the year and forage under the snow in colder regions. Life expectancy is less than 1½ years.

Geographic range

As currently recognized, the range of Preble’s shrew includes southern British Columbia, south to northeastern California, northern Nevada and Utah and east to western Wyoming and Colorado, and south to New Mexico and north to include much of Montana. However, a future taxonomic revision may split the species, restricting the name Sorex preblei to populations in Washington, Oregon, British Columbia, California and Nevada. 

In Washington, the only records of Preble’s shrew were from the Blue Mountains in 1956 to 1958, until 2004 when a single specimen was captured in Douglas County. There are no density estimates or data on population numbers in Washington or elsewhere. Preble’s shrews seem to be very rare, though this may partly be an artifact of inadequate sampling. Population trends can only be hypothesized from the reduction in steppe habitats; less than 50 percent of the historical shrubsteppe in Washington remains and much of the remainder is fragmented and degraded.

For a map of state/provincial conservation status and documented distribution of Preble’s shrew, check out NatureServe Explorer.