South Dakota mammals

American Ermine in South Dakota

Mustela erminea

Native to South Dakota

Not listed as nonindigenous in South Dakota by USGS NAS; treated as native to its mapped South Dakota 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.

Mustela Erminea headMustela erminea hibernicaMustela erminea uprightAmerican ermine standing alert on a wooden beamAmerican ermine peering from a mossy den entranceAmerican ermine in white winter coat crossing an alpine talus slope
Photo: Keven Law from Los Angeles, USA · CC BY-SA 2.0Mustela Erminea headPhoto: Alastair Rae from London, United Kingdom · CC BY-SA 2.0Mustela erminea hibernicaPhoto: Steve Hillebrand, USFWS · Public domainMustela erminea uprightPhoto: Robbie Hannawacker · CC0American ermine standing alert on a wooden beamPhoto: miaow7477 · CC0American ermine peering from a mossy den entrancePhoto: Игорь Загребин · CC0American ermine in white winter coat crossing an alpine talus slope

American Ermine in South Dakota, by the numbers

Rare in South Dakota 72nd most recorded of 100 mammals logged in South Dakota

15 occurrence records

Records from 2000–2026.

When to look for the American Ermine in South Dakota

Most sightings fall in March.

15 South Dakota 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 South Dakota records (table)
MonthRecords
January3
February0
March4
April1
May1
June2
July2
August0
September0
October0
November2
December0

Monthly american ermine occurrence records (iNaturalist and GBIF) in South Dakota, 2000–2026.

Seasonality

Year-round in South Dakota, with recorded sightings peaking in March, with a smaller rise in January.

Occurrence map

Where American Ermine has been recorded in South Dakota

15 records mapped · zoom and drag to explore

15 South Dakota records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
Altamont 1
Black Hills National Forest 1

Protected places with the most american ermine 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 South Dakota

CountyRecords
Pennington County 5
Brookings County 3
Sanborn County 2
Deuel County 2
Edmunds County 1
Hamlin County 1
Custer County 1

The complete county distribution, spread across 7 South Dakota counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

American ermines carry no NatureServe state rank on file in South Dakota, and all 7 of the state’s records come from iNaturalist with no GBIF specimen data, meaning what’s documented here traces entirely to casual sightings of a small, secretive weasel that’s easy to overlook in Black Hills forest and Custer State Park habitat.

Records scatter one or two at a time across four months, January, April, June, and November, too sparse a pattern in a dataset this small to draw any real seasonal conclusion, though the June bump (2 of the 7 sightings) offers the closest thing to a pattern here.

Occurrence data from iNaturalist.

Mustela Erminea head
Full species profile American Ermine Mustela erminea Size 17–33 cm6.7–13 in Weight 70–260 g2.5–9.2 oz Lifespan Up to 12.5 yr View the full profile

More mammals in South Dakota 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
  • 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"