Alaska mammals

Least Weasel in Alaska

Mustela nivalis

Native to Alaska S4 Apparently Secure in Alaska

Not listed as nonindigenous in Alaska by USGS NAS; native to its Alaska range.

IUCN Red List status

  1. LC
  2. NT
  3. VU
  4. EN
  5. CR
  6. EW
  7. EX

LC – Least Concern

Widespread and abundant; not at risk.

Least Weasel in Alaska, by the numbers

Rare in Alaska 80th most recorded of 108 mammals logged in Alaska

28 occurrence records
7 with iNaturalist photos
Jul 11, 2025 Last seen in Alaska

Records from 2000–2026.

28 total records count every Alaska occurrence from GBIF and iNaturalist; the map plots a georeferenced sample of 27; the monthly chart covers the 26 records with a full observation date.

When to look for the Least Weasel in Alaska

Most sightings fall in July to August.

26 Alaska occurrence records (iNaturalist and GBIF) by month of year, 2000–2026. Shows when the species is recorded, not a guarantee of presence. Based on a small number of dated records; the seasonal pattern may not be representative.

Monthly Alaska records (table)
MonthRecords
January1
February3
March0
April1
May0
June2
July6
August6
September3
October3
November1
December0

Monthly least weasel occurrence records (iNaturalist and GBIF) in Alaska, 2000–2026.

Seasonality

Year-round in Alaska, with recorded sightings peaking in July–August.

Occurrence map

Where Least Weasel has been recorded in Alaska

27 records mapped · zoom and drag to explore

27 Alaska records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
State Land Disposals - Other Than Municipal 2
Haines State Forest Resource Management Area 1
Gates of the Arctic National Park 1
State Tentatively Approved (tad) 1
State Patented 1

Protected places with the most least weasel sightings, from the USGS Protected Areas Database plus named mountain ranges, good spots to look, not a full breakdown, so they don't sum to the total.

Where it's recorded in Alaska

CountyRecords
Fairbanks North Star County 8
North Slope County 3
Southeast Fairbanks County 3
Kenai Peninsula County 2
Yukon-Koyukuk County 2
Matanuska-Susitna County 2
Bethel County 2
Haines County 1
Bristol Bay County 1
Nome County 1
Other localities 3

The complete county distribution, spread across 10 Alaska counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

Alaska has just 28 records for the least weasel, scattered a few at a time from the North Slope to the Kenai Peninsula, and the largest cluster, 8 of them, comes from the boreal forest around Fairbanks. That’s classic Interior Alaska terrain: black spruce forest, brushy field edges, and the vole and mouse burrows this weasel needs to hunt.

Its narrow body lets it follow rodents straight into their own tunnels, turning in spaces no fox or marten could fit through. Many Interior Alaska least weasels molt to white winter fur as days shorten, a change triggered by day length rather than temperature, so a white weasel can look oddly out of place if snow arrives late.

Records run heaviest in July and August, though sightings turn up in most months. Because this weasel spends so much time under snow and dense cover, a thin record count reflects how easily it goes unnoticed, not how rare it actually is across the Interior.

Occurrence data from iNaturalist and GBIF.

More mammals in Alaska in the atlas

Data & sources

The data and visualizations on this page draw on these open sources:

  • GBIFCC-BY 4.0occurrence records behind the range map, elevation, and record counts
  • iNaturalistCC0 / CC-BY / CC-BY-SAobservations, photos, and audio recordings
  • NatureServe ExplorerCC-BYthe state conservation rank
  • IUCN Red Listattributed factthe global conservation status
  • USGS NASpublic domainnative / introduced status
  • Natural Earthpublic domainthe relief basemap
  • USFSpublic domainnational-forest boundaries
  • USGS Protected Areas Databasepublic domainthe named parks, forests, and refuges behind "notable places to look"