Sorex dispar
long-tailed shrew

The range of Sorex dispar extends from Nova Scotia, Canada south through Eastern Tennessee and North Carolina (Nowak,1999). In the United States, they are found in greatest abundance throughout the Appalachian Mountain Range (PA Game Commission website, 2001).

Sorex dispar has a wide tolerance for altitudinal variation, as well as different types of vegetation. They can be found in cool, damp forests, both deciduous and mixed (Nowak, 1999). However, their preferred habitats are the moist forested areas of high altitude regions. Living primarily in mountainous environments, these shrews can be found at high densities along mountain streams and amid the debris surrounding rock-slides (Whitaker and Hamilton, 1998). In these rock-slide areas, they can often be found amongst the subterranean tunnels found in the rocky crevices between boulders (DiscoverLife website, 2001).

Sorex dispar is often confused with its close relative Sorex fumeus, the smoky shrew. Their appearance is quite similar and their ranges may overlap in some locations. However, Sorex dispar can be distinguished by several defining characteristics, including a more slender body and longer tail (Whitaker and Hamilton, 1998). They have a long snout and small eyes, with a long and thick tail. Their length ranges from 46-100 mm. and their weight ranges between 4-6 g., with a tail length that ranges between 25-82 mm (Nowak, 1999). They have a dark grey pelage with slightly paler under parts. Their teeth are sharp, pointed and often stained (PA Game Commission website, 2001).

Like many other shrews, this species is short-lived. Lifespan estimates for wild individuals rarely exceed 2 years. Other than predation, some other common causes of death include starvation, rapid temperature changes, floods, and fights with other individuals. (PA Game Commission website, 2001)

These long-tailed shrews are active both day and night and do not become seasonally inactive. They are primarily solitary animals and can be quite aggressive with one another when put in close proximity. Almost all of their time is spent foraging (Nowak, 1999).

Their home ranges are estimated to be between .25-1 acre.

Due to their size, these shrews forage day and night, often consuming twice their body weight in food every day. This ravenous need for food is a response to their active lifestyle and small size, which produces a large surface-area-to-volume ratio compared to larger mammals. Due to their greater heat loss, these small animals must consume a proportionally larger amount of food than larger species (Vaughn, 2000). Their foraging focuses mainly on small invertebrates and plant materials. They eat almost continuously, feeding mostly above the ground and amongst the debris (PA Game Commission website, 2001). Some of their more common foods are centipedes, beetles, and spiders, as well as flies and crickets (Richmond, 1950).

To avoid predation while foraging, Sorex dispar often feed at night. Also, they tend to remain concealed under the debris of the forest floor. Also, since they are often mistaken by predators for mice, these shrews have a distinct musky odor that may serve as a deterant to predators (PA Game Commission website, 2001).

Due to their relative rarity, not much is known about specific ecosystem roles for this species. However, like many other terrestrial shrew species, Sorex dispar likely plays a large role in controlling insect populations through their foraging (DiscoverLife website, 2001).

Since this species has such little direct human contact (due to their isolated habitats), they have little direct economic impact. However, due to their intense and constant consumption of insects, these shrews may have a positive effect on the farming industry by reducing the number of insect larvae and pupae that become pests (Banfield, 1974).

This species is rare, but is not specifically recognized under any major conservation status.