LRP - Licenses

LRP - Regulations

LRP - Permits

Recreation - Statewide

Recreation - Trapping

Recreation - Fishing

Recreation - Hunting

Env. Protection - Management

Env. Protection - Emergency

Env. Protection - Resources

To sign up for updates or to access your subscriber preferences, please enter your contact information below.

Share your observations

Share your observations of plants or non-game animals with the Natural Heritage Inventory

Rare animals
Find rare and non-game animals.
Rare plants
Learn about plants on the Natural Heritage Working List.
Rare lichens
Discover Wisconsin's lichens.
Natural communities
Explore Wisconsin's natural communities.
Other features
Discover unique resources.
Eagle license plate

Help care for rare plants and animals by ordering an Endangered Resources plate.

Contact information
For information on Wisconsin's rare animals, contact:
Rich Staffen
Conservation Biologist

Least Weasel (Mustela nivalis)



Least Weasel (Mustela nivalis) is the state's smallest weasel but exhibits typical mustelid form having a long, slender body and long neck. Its summer coat is chocolate-brown in color and lacks black on the tail and it molts to a white pelt during autumn (Oct-Nov). Least weasels are a grassland species found in a variety of open habitats such as marshlands, farmlands, grassy fields, and moist to wet prairies. The breeding season is typically during the spring and autumn, although it can occur throughout the year. Least weasels are among the smallest carnivores in the world and have a diet of mice, birds, eggs, insects, and young rabbits. This species is not actively tracked in the Natural Heritage Inventory Database, but it could be tracked in the future if there is further evidence of its decline.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Least Weasel (Mustela nivalis). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.

Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.

Mustela nivalis is not tracked by the Wisconsin Natural Heritage Inventory Program at this time (this species is not on the NHI Working List).
Summary Information
State Statusnone
Federal Status in Wisconsinnone
State RankSU
Global RankG5
Tracked by NHIW

Species guidance

A guidance document is not available at this time. Use the information from the other tabs and contact local biologists, as needed, to develop management and avoidance strategies.

Other resources

Links to additional Least Weasel information

Other links related to mammals



Least Weasel

Least weasel and cache of dead mice under cover board

Photo © Jeff Lorch.

Least Weasel

Least weasel in winter plumage

Photo © Peggy Popp.

Least Weasel

Least weasel in summer plumage

Photo © Peggy Popp.

Least Weasel

Least weasel in summer plumage

Photo © Peggy Popp.

Last revised: Monday, November 18, 2019