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- Kingdom - Animals - Animalia
  - Phylum - Vertebrates - Craniata
    - Class - Mammals - Mammalia
      - Order - Shrews - Eulipotyphla
        
        Family - Shrews - Soricidae
        
        Species - Northern Montane Shrew - Sorex obscurus

Northern Montane Shrew - Sorex obscurus

Other Names: Dusky or Montane Shrew, Sorex monticolus

Image Copyright and Usage Information

Native Species

Global Rank: G5
State Rank: S5
(see State Rank Reason below)

Agency Status
USFWS:
USFS:
BLM:

External Links

State Rank Reason (see State Rank above)

Species is relatively common within suitable habitat and widely distributed across portions of the state

Northern Montane Shrew (Sorex obscurus) Conservation Status Summary
State Rank: S5
Review Date = 09/12/2024
See the complete Conservation Status Rank Report

How we calculate Conservation Status Ranks

General Description

Pacific coast: pelage gray brown; median tine on anteriomedial edge of I1 usually large and robust; tail indistinctly bicolored; 5 or 6 pairs of friction pads on second to fourth digits of hind feet; level of pigmentation above level of median tine on I1; body size small to medium; U5 triangular, body of U1s not touching, P4 overlapping U5; zygomatic process of maxillary pointed (Carraway 1990).

Diagnostic Characteristics

See Carraway (1995) for a key to western North American soricids based primarily on dentaries.

Species Range

Montana Range Range Descriptions

Native

Observations in Montana Natural Heritage Program Database

Number of Observations: 349

(Click on the following maps and charts to see full sized version) Map Help and Descriptions

Relative Density

Recency

(Observations spanning multiple months or years are excluded from time charts)

Migration

Non-migratory.

Habitat

In western Montana, high altitude spruce-fir forest, alpine tundra. Also as low as 3000 ft. in mid-altitude forests. Occurs along streams and rivers east of Continental Divide and in isolated mountain ranges in central Montana (Hennings and Hoffmann 1977).

National Vegetation Classification System Groups Associated with this Species

Alpine

Alpine - Vegetated

Alpine Dwarf-Shrubland and Krummholz

Alpine Turf and Fellfield

Forest and Woodland

Deciduous Forest and Woodland

Great Plains Aspen Forest and Woodland

Great Plains Mesic Forest and Woodland

Rocky Mountain Aspen Forest and Woodland

Low Elevation - Xeric Forest and Woodland

Great Plains Ponderosa Pine Forest and Woodland

Rocky Mountain Ponderosa Pine Forest and Woodland

Montane - Subalpine Forest and Woodland

Cedar - Hemlock Forest

Dry Spruce-fir Forest

Interior PNW Douglas-fir Forest and Woodland

Lodgepole Pine Forest

Mesic Spruce-fir Forest

Montane Mesic Coniferous (Grand Fir - Douglas-fir - Western Larch) Forest

Rocky Mountain Douglas-fir Forest

Whitebark Pine - Subalpine Larch Forest and Woodland

Shrubland

Foothills - Montane Shrubland

Lowland - Montane Shrubland

Montane - Subalpine Mesic Shrubland

Mountain Mahogany Woodland and Shrubland

Sagebrush Shrubland

Basin and Wyoming Big (Threetip) Sagebrush Shrubland

Mountain Big Sagebrush Shrubland

Grassland

Lowland - Prairie Grassland

Great Plains Dry Mixedgrass Prairie

Great Plains Mesic Mixedgrass Prairie

Great Plains Solonetzic Grassland

Intermountain Sand Grassland

Rocky Mountain Low Elevation - Dry Grassland

Montane - Subalpine Grassland

Montane - Subalpine Dry Grassland

Montane - Subalpine Mesic Grassland and Meadow

Wetland and Riparian

Alkaline - Saline Wetlands

Great Plains Saline Marsh and Wet Meadow

Alpine Riparian and Wetland

Alpine - Subalpine Herbaceous and Dwarf-Shrub Riparian and Wetland

Peatland

Great Plains Alkaline Fen

Rocky Mountain Acidic Fen

Rocky Mountain Alkaline Fen

Riparian and Wetland Forest

Great Plains Floodplain Forest

Lowland - Montane Riparian Deciduous Forest

Montane - Subalpine Riparian Forest

Montane Forested Wetland

Riparian Shrubland

Great Plains Floodplain Shrubland and Herbland

Lowland - Montane Riparian Shrubland

Montane - Subalpine Riparian and Seep Shrubland

Wet Meadow and Marsh

Arid West Freshwater Marsh and Wet Meadow

Great Plains Freshwater Marsh

Great Plains Wet Meadow, Marsh and Shrub Swamp

Montane Wet Meadow and Marsh

Great Plains Wet Meadow, Riparian Shrubland and Fen

Recently Disturbed or Modified

Harvested Forest

Recently Logged

Insect-Killed Forest

Recent Insect/Disease Damage

Human Land Use

Agriculture

Pasture/Hay, Dryland

Developed

Developed - Vegetation

Food Habits

Similar to other long-tailed shrews: eats mostly invertebrates (van Zyll de Jong 1983).

Ecology

Non-breeders territorial. Breeders apparently not territorial (van Zyll de Jong 1983).

Reproductive Characteristics

First-year animals may not be reproductively active (van Zyll de Jong 1983).

Stewardship Responsibility

References

Literature Cited AboveLegend: View Online Publication
- Carraway, L.N. 1990. A morphologic and morphometric analysis of the 'Sorex vagrans species complex' in the Pacific coast region. Texas Tech Univ. Mus. Spec. Publ. (32): 1-76.
- Carraway, L.N. 1995. A key to recent Soricidae of the western United States and Canada based primarily on dentaries. Occasional Papers of the Natural History Museum, University of Kansas (175):1-49.
- Hennings, D. and R.S. Hoffmann. 1977. A review of the taxonomy of the Sorex vagrans species complex from western North America. Occasional Papers of the Museum of Natural History, the University of Kansas. 68: 1-35.
- Van Zyll de Jong, C.G. 1983. Handbook of Canadian mammals. 1. Marsupials and insectivores. National Museum of Natural Sciences, National Museums of Canada, Ottawa, Canada. 210 pp.
Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- Mezhzherin, V. A., and William O. Pruitt. 1964. Dehnel's phenomenon and its possible explanation. [Place of publication not identified]: [publisher not identified].
- Clothier, R.R. 1950. Contribution to the taxonomy and life history of Sorex vagrans monticola and Sorex obscurus obscurus. M.A. thesis. University of Montana. Missoula, MT.
- Cramer, P.C. 1992. Small mammal diversity and abundance in Douglas Fir old growth forests. M.Sc. Thesis. Bozeman, MT: Montana State University. 64 p.
- Foresman, K.R. 2001. The wild mammals of Montana. American Society of Mammalogists, Special Publication Number 12. Lawrence, KS. 278 pp.
- Foresman, K.R. 2012. Mammals of Montana. Second edition. Mountain Press Publishing, Missoula, Montana. 429 pp.
- Geppert, T. J. 1984. Small mammals of the Shield Trap, East Pryor Mountain, Montana. M.S. thesis. University of Iowa, Iowa City. 45 pp.
- Hanauska-Brown, L., B.A. Maxell, A. Petersen, and S. Story. 2014. Diversity Monitoring in Montana 2008-2010 Final Report. Montana Fish, Wildlife & Parks. Helena, MT. 78 pp.
- Hendricks, P. and M. Roedel. 2001. A faunal survey of the Centennial Valley Sandhills, Beaverhead County, Montana. Report to the U.S. Bureau of Land Management and U.S. Fish and Wildlife Service. Montana Natural Heritage Program, Helena, MT. 44 p.
- Hennings, D.N. 1970. Systematics of the Sorex vagrans-obscurus complex revisited. M.S. thesis. University of Montana, Missoula. 113 pp.
- Hoffmann, R. S. and R. D. Taber. 1960. Notes on Sorex in the northern Rocky Mountain alpine zone. Journal of Mammalogy 41(2): 230-234.
- Joslin, Gayle, and Heidi B. Youmans. 1999. Effects of recreation on Rocky Mountain wildlife: a review for Montana. [Montana]: Montana Chapter of the Wildlife Society.
- Lazaro, J., D.K. Dechmann, S. LaPoint, M. Wikelski, and M. Hertel. 2017. Profound reversible seasonal changes of individual skull size in a mammal. Current Biology. 27(20).
- McCaughey, W.W. 1990. Biotic and microsite factors affecting Pinus albicaulis establishment and survival. Ph.D. Dissertation. Bozeman, MT: Montana State University. 78 p.
- McCracken, K. E. 1990. Microhabitat and dietary partitioning in three species of shrews at Yellow Bay, Montana. M.A. thesis. University of Montana, Missoula. 38 pp.
- Oechsli, L.M. 2000. Ex-urban development in the Rocky Mountain West: consequences for native vegetation, wildlife diversity, and land-use planning in Big Sky, Montana. M.Sc. Thesis. Montana State University, Bozeman. 73 p.
- Ports, M. A. and S. B. George. 1990. Sorex preblei in the northern Great Basin. Great Basin Naturalist 50: 93-95.
- Reichel, J.D. 1986. Habitat use by alpine mammals in the Pacific Northwest. Arctic and Alpine Research. 18(1): 111-119.
- Reichel, J.D. and S.G. Beckstrom. 1994. Northern bog lemming survey: 1993. Unpublished report. Montana Natural Heritage Program. Helena, MT. 87 pp.
- Reid, F. 2006. Peterson Field Guide to Mammals of North America, 4th Edition. Houghton Mifflin Company: Boston and New York, 608 pp.
- Smith, M. E. and M. C. Belk. 1966. Sorex monticolus. Mamm. Species 528: 1-5.
- Sutter, J., J. C. Munger, and D. A. Hengel. 1999. Sorex monticolus in shrub steppe habitat in the northern Great Basin. Great Basin Naturalist 59:102-104.
- Woodman, N. 2018. American recent Eulipotyphla Nesophontids, Solenodons, Moles, and Shrews in the New World. Smithsonian Contributions to Zoology 650. 108 p.
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Citation for data on this website:
Northern Montane Shrew — Sorex obscurus. Montana Field Guide. Montana Natural Heritage Program and Montana Fish, Wildlife and Parks. Retrieved on December 14, 2025, from https://FieldGuide.mt.gov/speciesDetail.aspx?elcode=AMABA01430