How to identify it
Typical weasel form: long body, short legs, triangular head, slightly protruding round ears. [1][2]
White winter coat with a black tail tip. [1][2]
Summer: chocolate-brown back, yellowish-white underside up to the upper lip. [1][2]
Body 170-330 mm; tail about 35% of body length; males about twice the mass of females. [1][2]
Compared with the american ermine: Same appearance; separated by range, with M. richardsonii across most of Canada and the northern US. [1][2]
Species it is confused with
Check these before deciding what you are looking at. If you are not certain what it is, do not shoot.
- American ermine · Mustela richardsonii
Where it lives
Riparian woodlands, marshes, shrubby fencerows and open areas adjacent to forest or shrub borders. [1][2]
How it behaves
Uses riparian woodlands, marshes, fencerows and open areas next to forest [1][2]
Where it is listed for legal take
These authorities list this species for legal take in their own regulations.
Where legal take is listed
- Alaska — trapping · 2026-2027 Alaska Trapping Regulations No. 67
Being listed is not an open season. Seasons, zones, licences, methods and limits decide whether this animal may be taken on a given day and place — check Hunt or the authority before you go. Listings read 2026-09-30.
Where it is found
Much of Eurasia; in North America, Alaska and western Yukon to most of Arctic Canada and east to Greenland per NatureServe. The widespread North American animal is now M. richardsonii.
Sources
Every claim above is attributed to one of these published sources.
NatureServe · reviewed 2026-09-30
NatureServe
University of Michigan Museum of Zoology · reviewed 2026-09-30
University of Michigan Museum of Zoology