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Long-tailed or Rock Shrew

This slender-bodied, slate gray insectivore named for its long tail or habitat, depending on which common name one chooses, holds center stage among some small mammal specialists. Entire chapters of its basic life history remain unknown. The sketchy information that is available results from several hundred trapped specimens.

(Sorex dispar Batchelder)

From: Saunders, D. A. 1988. Adirondack Mammals. State University of New York, College of Environmental Science and Forestry. 216pp.

Order: Insectivora
Family: Soricidae

Overall length of the rock shrew is 102-135 mm (4-5.3 in) which includes a 51-58 mm (2-2.3 in) tail that becomes progressively scaly and less haired with age. The front portion of the skull is narrower than corresponding areas of other Sorex, presumably for efficient foraging among rock crevices. Unlike the smoky shrew (which it resembles), the rock shrew even in summer is slate-gray in color both above and below. Its tail is proportionally longer than the smoky shrew’s being about 80-90% of the combined head-body length (verses 60-70% for the smoky shrew). An adult rock shrew weighs about 3-8 g (.11-.29 oz). This species was first described from a specimen caught in the Adirondacks on September 9, 1895 in Keene Township, Essex County, New York by Charles F. Batchelder

Range and Habitat

With few exceptions, the rock shrew requires a cool, moist site with a deep layer of moss-covered rocks or boulders. These conditions occur in many plant communities within the Adirondacks, e.g., along streams, among talus; rock slides; in deciduous, coniferous, and mixed forests; alpine meadows; and even the “artificial talus” of road construction and mining operations. Most records are for the central Adirondacks from 213-1616 m (700-5300 ft). The difficulties associated with finding and capturing a tiny mammal that lives under rocks suggests its limited distribution is more a artifact of capture effort and techniques than of restricted range or local, disjunct populations. The geographic range for the rock shrew is a narrow band in the mountainous region of eastern North America from North Carolina into Maine, with an additional population occurring in southeastern New Brunswick.

Food and Feeding Behavior

Little information is available about the food preferences of the rock shrew, but what is known suggests a diet of insects, spiders, and centipedes. Activity and Movement: The seasonal and daily activity patterns are unknown. Reproduction: Only a handful of specimens offer clues about breeding habits. These indicate litter size may vary from 2-5, and that the reproductive season extends from early spring, April or May, until late summer, through August.



Social Behavior

The behavioral ecology, social organization, mating system, and means of communication are unknown, but are likely to exhibit some unique specializations for a life among dark, damp stones.

Additional References 

Harper, F. 1929. Notes on the mammals of the Adirondacks. New York Museum Handbook, 8:51-118.

Harper, F. and J. S. Harper. 1929. Animal habits in certain portions of the Adirondacks. New York State Museum Handbook, 8:10-49

Kirkland, G. L., Jr. 1981. Sorex dispar and Sorex gaspensis. Mammalian Species 155:1-4.

Kirkland, G. L., Jr. and H. M. Van Deusen. 1979. The shrews of the Sorex dispar group: Sorex dispar Batchelder and Sorex gaspensis Anthony and Goodwin. American Museum Novitates, 2675-21.