South Dakota mammals

Big Brown Bat in South Dakota

Eptesicus fuscus

Native to South Dakota S5 Secure in South Dakota

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

Big Brown Bats (Eptesicus fuscus)Big brown bat flying in daylight with wings spreadBig brown bat flying at night with wings spreadBig brown bat roosting on lichen-covered tree barkBig brown bat roosting on a wooden structure
Photo: Connor Long · CC BY-SA 4.0Big Brown Bats (Eptesicus fuscus)Photo: rhododendrites · CC-BY-SABig brown bat flying in daylight with wings spreadPhoto: Dan Riskin · CC-BYBig brown bat flying at night with wings spreadPhoto: Rita Clare · CC0Big brown bat roosting on lichen-covered tree barkPhoto: Bonnie Isaac · CC0Big brown bat roosting on a wooden structure

Big Brown Bat in South Dakota, by the numbers

Occasional in South Dakota 53rd most recorded of 100 mammals logged in South Dakota

210 occurrence records
26 with iNaturalist photos
Apr 2, 2025 Last seen in South Dakota

Records from 2000–2026.

210 total records count every South Dakota occurrence from GBIF and iNaturalist; the monthly chart covers the 204 records with a full observation date.

When to look for the Big Brown Bat in South Dakota

Most sightings fall in July.

204 South Dakota occurrence records (iNaturalist and GBIF) by month of year, 2000–2026. Shows when the species is recorded, not a guarantee of presence.

Monthly South Dakota records (table)
MonthRecords
January1
February2
March4
April12
May8
June40
July116
August17
September1
October1
November2
December0

Monthly big brown bat occurrence records (iNaturalist and GBIF) in South Dakota, 2000–2026.

Seasonality

Year-round in South Dakota, with recorded sightings peaking in July.

Occurrence map

Where Big Brown Bat has been recorded in South Dakota

210 records mapped · zoom and drag to explore

210 South Dakota records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
Wind Cave National Park 17
Sand Creek Recreation Area 13
Badlands National Park 7
Black Elk Wilderness 5
Black Hills National Forest 2
Big Sioux 1
Union Grove 1
Jewel Cave National Monument 1

Protected places with the most big brown bat 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
Jackson County 33
Lawrence County 32
Custer County 30
Bon Homme County 30
Fall River County 22
Clay County 20
Harding County 11
Pennington County 8
Minnehaha County 7
Brookings County 7
Davison County 2
Brown County 2
4 other counties 6

The complete county distribution, spread across 16 South Dakota counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

Big brown bats carry one of the more lopsided source ratios in this South Dakota rank tier: 205 GBIF records against just 26 from iNaturalist, nearly eight to one, reflecting how thoroughly specimen and survey data document this widespread, building-roosting bat compared to casual photography. NatureServe rates the state population S5, secure, fitting a species that adapts readily to human structures across South Dakota.

July alone accounts for 6 of the year’s monthly-tallied sightings, tracking peak summer activity when maternity colonies are active and insects are most abundant for foraging; April shows zero records, a gap that likely reflects the transition period between winter hibernation and full spring emergence.

Occurrence data from iNaturalist and GBIF.

Big Brown Bats (Eptesicus fuscus)
Full species profile Big Brown Bat Eptesicus fuscus Size 7.5 cm3 in Weight 17 g0.6 oz Lifespan 19 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
  • 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"