BC Conservation Data Centre: Species Summary
Mustela nivalis
Least Weasel
| Scientific Name: | Mustela nivalis Linnaeus, 1766 | ||||||||||
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| English Name: | Least Weasel | ||||||||||
| Classification / Taxonomy | |||||||||||
| Scientific Name - Concept Reference: | Wilson, D. E., and D. M. Reeder (editors). 1993. Mammal species of the world: a taxonomic and geographic reference. Second edition. Smithsonian Institution Press, Washington, DC. xviii + 1206 pp. Available online at: http://www.nmnh.si.edu/msw/. | ||||||||||
| Classification Level: | Species | ||||||||||
| Species Group: | Vertebrate Animal | ||||||||||
| Species Code: | M-MUNI | ||||||||||
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| Conservation Status / Legal Designation | |||||||||||
| Global Status: | G5 (Apr 2016) | ||||||||||
| Provincial Status: | S4 (Mar 2024) | ||||||||||
| BC List: | Yellow | ||||||||||
| Provincial FRPA list: | |||||||||||
| Provincial Wildlife Act: | |||||||||||
| COSEWIC Status: | |||||||||||
| SARA Schedule: | |||||||||||
| General Status Canada: | 4 - Secure (2005) | ||||||||||
| Ecology & Life History | |||||||||||
| General Description: | |||||||||||
| Global Reproduction Comments: | May breed throughout the year but mainly in spring and late summer. When rodents are plentiful, may breed in winter under snow. Gestation lasts 34-37 days, including the 10-12 days between fertilization and implantation. Litter size averages 4-5 in temperate zone, higher in arctic latitudes. Commonly two litters/year. Young are tended by both parents, weaned by 6-7 weeks. Family groups break up when young are about 9-12 weeks old. Spring-born females are sexually mature in 3-4 months (may produce a litter in their first summer), males in 8 months. Reproductive output increases when food is abundant (more young are born, greater survivorship). | ||||||||||
| Global Ecology Comments: |
Home range size varies with conditions; up to 26 ha in males, up to 7 ha in females; in England, average home range was 7-15 ha for males, 1-4 ha for females (King 1975). Basically solitary, except during breeding season and when females have young. High dispersal rate, good ability to colonize vacant habitat when rodent populations increase. Density fluctuates with rodent populations; 0.2-1.0/ha in favorable conditions, average as low as 1-7/100 ha over wider areas (Erlinger 1974, Golley 1960, Sheffield and King 1994). Mortality rate is high (overall annual rate is 75-90%); average age at death is less than one year. Predators include various Carnovora, raptors, and possibly snakes. |
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| Migration Characteristics: (Global / Provincial) | |||||||||||
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Nonmigrant: Local Migrant: Distant Migrant: Within Borders Migrant: |
Y / N / N / na / |
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| Habitats: (Type / Subtype / Dependence) |
Agriculture / Cultivated Field / Facultative - occasional use
Agriculture / Hedgerow / Facultative - occasional use Agriculture / Pasture/Old Field / Facultative - occasional use Alpine/Tundra / Alpine Grassland / Unknown Alpine/Tundra / Alpine/Subalpine Meadow / Unknown Alpine/Tundra / Krummholtz / Facultative - occasional use Alpine/Tundra / Tundra / Facultative - occasional use Forest / Conifer Forest - Dry / Facultative - occasional use Forest / Conifer Forest - Mesic (average) / Facultative - occasional use Forest / Deciduous/Broadleaf Forest / Facultative - occasional use Grassland/Shrub / Grassland / Facultative - occasional use Grassland/Shrub / Meadow / Facultative - frequent use Grassland/Shrub / Shrub - Logged / Facultative - frequent use Grassland/Shrub / Shrub - Natural / Facultative - frequent use Riparian / Gravel Bar / Facultative - occasional use Riparian / Riparian Forest / Facultative - occasional use Riparian / Riparian Herbaceous / Facultative - occasional use Riparian / Riparian Shrub / Facultative - occasional use Rock/Sparsely Vegetated Rock / Rock/Sparsely Vegetated Rock / Facultative - frequent use Subterranean / Sub-soil / Facultative - occasional use Wetland / Bog / Facultative - frequent use Wetland / Fen / Facultative - frequent use Wetland / Marsh / Facultative - frequent use Wetland / Swamp / Facultative - frequent use |
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| Global Habitat Comments: | Habitat varies geographically and includes open forests, farmlands and cultivated areas, grassy fields and meadows, riparian woodlands, hedgerows, alpine meadows, scrub, steppe and semi-deserts, prairies, coastal dunes, and sometimes rural residential areas; snow cover is not an obstacle; generally avoids deep dense forest and sandy desert. When inactive, occupies burrow made by vole or mole, or rests in nest in hole in wall of building or under corn shock or similar site. Den site may change often. Young are born in abandoned underground burrows made by other mammals (or similar secluded sites). | ||||||||||
| Food Habits: |
Carnivore: Adult, Immature
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| Global Food Habits Comments: | Specialist predator of small mammals, especially voles, lemmings, and other mice. When small rodents are scarce, may consume other small vertebrates, insects, or worms. Young are adept at killing mice at 7 weeks. | ||||||||||
| Global Phenology: |
Circadian: Adult, Immature
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| Global Phenology Comments: | Active day or night throughout the year. | ||||||||||
| Provincial Phenology: (1st half of month/ 2nd half of month) |
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| Colonial Breeder: | N | ||||||||||
| Length(cm)/width(cm)/Weight(g): | 21/ / 50 | ||||||||||
| Elevation (m) (min / max): |
Global:
Provincial: |
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| Distribution | |||||||||||
| Endemic: | N | ||||||||||
| Global Range Comment: | Circumboreal, Holarctic distribution. Western Hemisphere: most of Canada and Alaska south to British Columbia, Montana, Wyoming, Oklahoma, Missouri, Ohio, Virginia, and along the Appalachians to the Great Smoky Mountains (North Carolina, Tennessee). Range has expanded southward in the Great Plains since the mid-1960s as the climate has become cooler and more mesic (Frey 1992). Thought to be rare (though sometimes locally fairly common) throughout the range in the southeastern U.S., but actual status is uncertain (Handley 1991). Introduced in New Zealand, Malta, Crete, the Azore Islands, and apparently also Sao Tome off west Africa (Sheffield and King 1994). Ranges to 3660 m in mountains of Eurasia. | ||||||||||
| Authors / Contributors | |||||||||||
| Global Information Author: | |||||||||||
| Last Updated: | Sep 20, 1994 | ||||||||||
| Provincial Information Author: | |||||||||||
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| References and Related Literature | |||||||||||
Baker, R. H. 1983. Michigan mammals. Michigan State University Press. 642 pp. |
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Banfield, A. W. F. 1974. The mammals of Canada. University of Toronto Press, Toronto, Canada. 438 pp. |
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Erlinger, S. 1974. Distribution, territoriality, and numbers of the weasel Mustela nivalis in relation to prey abundance. Oikos 25(3):308-314. |
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Frey, J. K. 1992. Response of a mammalian faunal element to climatic changes. J. Mamm. 73:43-50. |
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Golley, F.B. 1960. Energy dynamics of a food chain of an old-field community. Ecol. Manag. 30(2):187-206. |
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Hall, E. R. 1981a. The Mammals of North America, second edition. Vols. I & II. John Wiley & Sons, New York, New York. 1181 pp. |
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Hall, E.R. 1951. American Weasels. Univ. Kansas Publication, Museum Natural History, 4:1-466. |
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Hamilton, W. J., Jr., and J. O. Whitaker, Jr. 1979. Mammals of the eastern United States. Cornell Univ. Press, Ithaca, New York. 346 pp. |
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Handley, C. O., Jr. 1991. Mammals. Pages 539-616 in K. Terwilliger, coordinator. Virginia's endangered species: proceedings of a symposium. McDonald and Woodward Publishing Company, Blacksburg, Virginia. |
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Hatler, D.F., Nagorsen, D.W. and Beal, A.M., 2008. Carnivores of British Columbia (Vol. 5). Victoria, British Columbia, Canada: Royal BC Museum. |
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Heidt, G.A. 1970. The least weasel Mustela nivalis Linnaeus.Developmental biology in comparison with other North American Mustela. Michigan State Univ., Publ. Mus., Biol. Ser., 4(7):227-282. |
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Jones, J. K., Jr., R. S. Hoffman, D. W. Rice, C. Jones, R. J. Baker, and M. D. Engstrom. 1992a. Revised checklist of North American mammals north of Mexico, 1991. Occasional Papers, The Museum, Texas Tech University, 146:1-23. |
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King, C. 1989. The natural history of weasels and stoats. Cornell Univ. Press, Ithaca. xviii + 253 pp. |
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King, C. M. 1975. The home range of the weasel (MUSTELA NIVALIS) in an English woodland. Journal of Animal Ecology 44:636-668. |
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Schwartz, C. W., and E. R. Schwartz. 1981. The wild mammals of Missouri. University of Missouri Press, Columbia. 356 pp. |
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Sheffield, S. R., and C. M. King. 1994. Mustela nivalis. Am. Soc. Mamm., Mammalian Species No. 454:1-10. |
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van Zyll de Jong, C. G. 1992. A morphometric analysis of cranial variation in Holarctic weasels (MUSTELA NIVALIS). Zeitschrift fur Saugetierkunde 57:77-93. |
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Wilson, D. E., and D. M. Reeder (editors). 1993. Mammal species of the world: a taxonomic and geographic reference. Second edition. Smithsonian Institution Press, Washington, DC. xviii + 1206 pp. Available online at: http://www.nmnh.si.edu/msw/. |
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Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.
Suggested Citation:
B.C. Conservation Data Centre. 1994. Species Summary: Mustela nivalis. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Oct 3, 2026).