Mammal Species of the World
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- Original description: Batchelder, C.F., 1896. An undescribed shrew of the genus Sorex, p.133. Proceedings of the Biological Society of Washington, 10:133-134.
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).
Biogeographic Regions: nearctic (Native )
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (20,000-2,500,000 square km (about 8000-1,000,000 square miles)) Appalachian Mountains, from Nova Scotia (Scott 1987) and southeastern New Brunswick outhward along the mountains to North Carolina and Tennessee (Kirkland, in Wilson and Ruff 1999). Recent data indicate that populations formerly recognized as Sorex gaspensis actually should be included in S. dispar, so the range of S. dispar extends northeastward to the Gaspe Peninsuala in Quebec and Cape Breton Island in Nova Scotia (Rhymer et al. 2004).
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).
Range mass: 4 to 6 g.
Range length: 46 to 100 mm.
Length: 14 cm
Weight: 6 grams
Size in North America
Average: 119.5 mm
Range: 103-136 mm
Average: 4.9 g
Range: 3.1-8.3 g
Often confused with the smoky shrew (Sorex fumeus), but Dispar has a longer, thicker, and hairier tail and is uniformly slate-gray in all seasons. S. FUMEUS turns brownish in summer. In winter, when the two species are similarly colored, S. FUMEUS differs in having lighter belly hair.
The unicuspid tooth row of Dispar is relatively narrow, with the third unicuspid equal to or slightly smaller than the fourth. The fifth unicuspid is larger than that of S. FUMEUS but is smaller than the third. Dispar has less tooth pigmentation.
Subspecies BLITCHI averages darker in color and larger in external and cranial dimensions than subspecies Dispar (Webster 1987).
Habitat and Ecology
The shrew's partly subterranean existence among rocks makes observation, direct or indirect, very difficult. Virtually all data comes from trapping. Nothing is known of territoriality or home range size. The same predators that feed on other shrews probably take long-tailed shrews, e.g., weasels, snakes, hawks and owls, but there is no specific information. External parasites include fleas, ticks, mites and chiggers. While no internal parasites have been reported, nematodes and tapeworms are common in other shrew species. Examination of the digestive tracts of long-tailed shrews indicates a diet primarily of small invertebrates. Some better-known species of shrews are reported to consume approximately their own weight in food daily, and, with their high metabolic rates, may die within a few hours when deprived of food.
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).
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest ; mountains
Comments: Mountainous, forested areas (deciduous or evergreen) with loose talus. Rocky damp areas with deep crevices covered by leaf mold and roots are preferred. May occur along small mountain streams. Will use artificial talus created by road construction and pit mines. "Sorex dispar is probably the most stenotopic mammal in eastern North America..." (Webster 1987). Trapping results reported by Richmond and Grimm (1950) suggest that Long-tailed Shrews spend most of their time in the labyrinth of spaces between rocks about a foot beneath the surface. Nest sites are usually associated with natural subterranean tunnels among boulder crevices.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
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).
Animal Foods: insects; terrestrial non-insect arthropods
Primary Diet: carnivore (Insectivore , Eats non-insect arthropods)
Comments: Examination of the digestive tracts of long-tailed shrews indicates a diet primarily of small invertebrates. Three Pennsylvania specimens yielded mostly centipedes (Richmond and Grimm 1950), six individuals from Great Smoky Mountains National Park contained chiefly insects, including beetles, with a lesser amount of spiders (Conaway and Pfitzer 1952), and Connor (1960) reported these food percentages from nine New York specimens: insects 74.9, centipedes 14.7, spiders 10.6, and plant material 1.1. Some better-known species of shrews are reported to consume approximately their own weight in food daily, and, with their high metabolic rates, may die within a few hours when deprived of food.
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).
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).
This list may not be complete but is based on published studies.
Known prey organisms
This list may not be complete but is based on published studies.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 81 to >300
Comments: There are a number of occurrences, but many are pre-1980. This species is not particularily easy to trap, and the actual number of occurrences far exceed what is currently known (Master, pers. comm., 1994).
10,000 to >1,000,000 individuals
Comments: Many biologists agree with Charles Bier (pers. comm.) who reported: "Given the habitat, which is usually difficult to survey, it is probably a lot more common than the specimen records indicate." In a 1980 (?) study in the White Mountains (New Hampshire), 100 long-tailed shrews (half the catch of small mammals could not be identified) were found (pitfall traps) evenly dispersed throughout six forested habitat types (Master pers. comm., 1994).
Very little is known about ecology, behavior and reproductive biology. The shrew's partly subterranean existence among rocks makes observation--direct or indirect--very difficult. Virtually all our data come from trapping.
Nothing is known of territoriality or home range size. Shrew species generally tend to be territorial and asocial; territoriality tends to break down in the breeding season and when food resources are abundant. Researchers have recorded home range sizes for various species from 75 sq m to 12,000 sq m (2.97 acres) (Churchfield 1990).
Shrew population densities depend on species, season, habitat, and perhaps prey abundance. Recorded densities for various North American shrew species range from 0 to 30 per ha (0 to 12 per acre) (Churchfield 1990). Again, few figures are available for the long-tailed shrew, but some biologists think it is more common than captures would indicate due to difficulty of trapping in the subterranean talus microhabitat. Richmond and Grimm (1950) reported that seven long-tailed shrews were trapped on one acre (0.4 per ha) in Pennsylvania.
The same predators that feed on other shrews probably take long-tailed shrews, e.g., weasels, snakes, hawks and owls, but we have no specific information. External parasites include fleas, ticks, mites and chiggers. While no internal parasites have been reported, nematodes and tapeworms are common in other shrew species.
Life History and Behavior
Comments: Continuously active both day and night.
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)
Status: wild: 2 years.
The reproductive season for Sorex dispar is between April through August and they usually have several litters throughout each year. The average litter size is between four and seven, and the young are born helpless and unfurred (Nowak, 1999). They are placed quickly into a nest made of grasses and leaves, where they reumain until they are weaned. The nests are usually 10-20 cm in diameter (DiscoverLife website, 2001). Due to the rare opportunities for study of Sorex dispar, not much is known about their reproductive and behavioral development. The newborns are usually placed in a ball of vegetation directly after birth. After four or five weeks, the young are weaned and partially independent. Usually, the young spend the next several weeks foraging close to their mother before becoming completely independent (Nowak, 1999).
Average weaning age: 4-5 weeks.
Parental Investment: altricial ; female parental care
Breeding occurs in spring and summer, possibly late April to August (Kirkland and Van Deuen 1979). One or two litters may be produced from May through August, with two to five young per litter (Tate 1935, Richmond and Grimm 1950). Sexually maturity is reached in less than a year. Like other shrews, this species probably does not survive beyond about 18 months.
Molecular Biology and Genetics
Statistics of barcoding coverage: Sorex dispar
Public Records: 0
Specimens with Barcodes: 3
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1996Lower Risk/least concern
This species is rare, but is not specifically recognized under any major conservation status.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
National NatureServe Conservation Status
Rounded National Status Rank: N1 - Critically Imperiled
Rounded National Status Rank: N4 - Apparently Secure
NatureServe Conservation Status
Rounded Global Status Rank: G4 - Apparently Secure
Reasons: An Appalachian Mountains endemic with a habitat that is not often suited for human use and development; due to the difficulty of trapping this species, there are probably more occurrences than are currently known.
Global Short Term Trend: Relatively stable (=10% change)
Comments: Likely stable over most of the range, but few population data are available.
Degree of Threat: C : Not very threatened throughout its range, communities often provide natural resources that when exploited alter the composition and structure over the short-term, or communities are self-protecting because they are unsuitable for other uses
Comments: Habitat destruction is a threat, but less so than for many rare species because the preferred habitat, talus, is often unsuitable for development, and provides a very uniform subterranean environment that is not highly vulnerable to disturbance. However, ski area expansion may be a threat to some populations, as in Vermont (Fichtel, pers. comm., 1992). Highway construction may create more habitat than it destroys, as long-tailed shrews have been collected in the artificial talus slopes of road cuts (Conway and Pfitzer 1952). Logging is unlikely to adversely impact this shrew; Kirkland (1977) showed that shrews persisted in recently clearcut red spruce stands in West Virginia. "Habitat specialization in a species frequently is associated with a limited geographical distribution and small populations. Species having such characteristics ... may be subject to extinction caused by stochastic events" (Kirtland 1986). Shrews feed on invertebrates and may accumulate and concentrate pesticides and heavy metals in their tissues. Short-tailed shrews (Blarina brevicauda) were found to contain DDT nine years after application of the pesticide to a forest habitat (Dimond and Sherburne 1969). "Contamination of habitats, and the resultant effects on the food chain, by mining and refining of metalliferous ores, by motor exhausts and even the application of sewage sludge to land, is becoming more widespread. Shrews from contaminated grasslands have been found to accumulate some of the highest concentrations of metals recorded in wildlife" (Churchfield 1992). Long-term high deer populations could be a problem (Brooks and Healy 1988).
Restoration Potential: Where extirpated from habitat that has been restored or remained in good condition, this shrew probably could be successfully reintroduced from nearby populations. Many populations are on national forests or other federal lands, suggesting good potential for restoration, management, and protection.
Preserve Selection and Design Considerations: Aside from habitat considerations (see GHABCOM), no specific recommendations can be made at the present time.
Management Requirements: Protection of habitat from gross disturbance is the primary management requirement.
Management Research Needs: Research is needed in all aspects of biology, ecology, behavior, and life history. The minimum population size needed to maintain a genetically viable population in fragmented habitats should be examined.
Global Protection: Many to very many (13 to >40) occurrences appropriately protected and managed
Comments: Many populations are in national forests, parks, or other public lands, and many are in areas protected by their remoteness.
Needs: Protection of habitat from gross disturbance is the primary protection need. Habitats with these shrews should be protected from contamination by heavy metals and pesticides.
Relevance to Humans and Ecosystems
Economic Importance for Humans: Positive
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).
Positive Impacts: controls pest population
Stewardship Overview: The long-tailed shrew is an Appalachian endemic with very specific habitat requirements: cool, damp forest with deep talus. Very little is known of its status or natural history, so little can be given in the way of management suggestions.
This shrew is slate grey in colour with a pointed snout, a long tail and lighter underparts. It is found on rocky slopes in mountainous areas along the Atlantic coast from Gaspé Peninsula, Quebec and Cape Breton Island, Nova Scotia to northern Georgia. It eats insects and spiders. Predators include hawks, owls, and snakes.
The northernmost examples of this species were until recently thought to be a separate species, the Gaspé shrew (S. gaspensis) inhabiting the Gaspé Peninsula and Cape Breton Island. However, a 2004 study indicated that the two species were conspecific, with the long-tailed shrew exhibiting a cline towards a smaller size at the northern edge of its range. As the Gaspé shrew, it was first described in A new species of shrew from the Gaspé Peninsula in no. 109, 1924 of American Museum Novitates, a publication of the American Museum of Natural History. When they were regarded as separate species, it was recognized that the Gapsé and long-tailed shrews inhabited similar habitats but were thought to be sympatric species with adjacent ranges. They are now generally accepted to be the same species, with gaspensis a junior synonym and not even a subspecies.
The long tailed shrew has an unusually small range. It is found in central New York (the Adirondacks and Catskills) and a small area in Pennsylvania. In Massachusetts, the long-tailed shrew is only found in Berkshire County.
|Wikispecies has information related to: Sorex dispar|
- Hutterer, R. (2005). Wilson, D. E.; Reeder, D. M, eds. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. p. 287. ISBN 978-0-8018-8221-0. OCLC 62265494.
- Whittaker, J.C., Hammerson, G., Master, L. & Norris, S.J. (2008). "Sorex dispar". IUCN Red List of Threatened Species. Version 2011.2. International Union for Conservation of Nature. Retrieved 18 February 2012.
- Rhymer, J. M., Barbay, J. M. and Givens, H. L. (2004). "Taxonomic relationship between Sorex dispar and S. gaspensis: inferences from mitochondrial DNA sequences". Journal of Mammalogy 85 (2): 331. doi:10.1644/BER-003.
- Munkwitz, Nicole (2002). "Sorex gaspensis". Animal Diversity Web. Retrieved 25 March 2012.
|This article about a red-toothed shrew is a stub. You can help Wikipedia by expanding it.|
Names and Taxonomy
Comments: French and Kirkland (1983) concluded from morphological data indicate that S. dispar and S. gaspensis are not conspecific. However, the only significant difference between the two taxa is size, with S. gaspensis smaller than S. dispar (Kirkland and Van Deusen 1979, French and Kirkland 1983). Yet Sorex dispar exhibits a south to north decreasing cline in body size, suggesting the possibility that S. gaspensis is not a distinct species but rather simply represents the northern extent of the S. dispar cline. Accordingly, Rhymer et al. (2004) found that the apparent distributional gap between S. dispar and S. gaspensis is not as large as previously believed (if in fact it exists at all) and that a morphological cline between dispar and gaspensis cannot be ruled out. Additionally, using mtDNA d-loop sequences, Rhymer et al. (2004) found that S. gaspensis and S. dispar cluster with no taxonomic or geographic structure, suggesting that they are conspecific. Shafer et al. (2008) analyzed cytochrome-b sequences and inter-SINE fingerprinting data and concluded that dispar and gaspensis constitute a single species composed of a monophyletic group of genetically highly similar shrews.
Fumagalli et al. (1999) present a phylogenetic analysis of the genus Sorex based on mitochondrial DNA sequences. See George (1988) for electrophoretic study of systematic relationships among Sorex species.