Montana mammals

Townsend's Big-eared Bat in Montana

Corynorhinus townsendii

Native to Montana S3 Vulnerable in Montana

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

IUCN Red List status

LC – Least Concern

Widespread and abundant; not at risk.

Photo: Josh Weaver · CC BY 4.0Townsend's big-eared bat roosting on a cave wallPhoto: Brandon McCracken · CC BY 4.0Townsend's big-eared bats tucked into a rock crevicePhoto: Hajenga Jeff, U.S. Fish and Wildlife Service · Public domainCluster of hibernating Virginia big-eared bats on a cave ceilingPhoto: Stihler Craig, U.S. Fish and Wildlife Service · Public domainVirginia big-eared bat hanging from a stone wallPhoto: Pinnacles National Park · CC BY 4.0Townsend's big-eared bat roosting in a rocky crevice

Photo: Josh Weaver · CC BY 4.0Townsend's big-eared bat roosting on a cave wallPhoto: Brandon McCracken · CC BY 4.0Townsend's big-eared bats tucked into a rock crevicePhoto: Hajenga Jeff, U.S. Fish and Wildlife Service · Public domainCluster of hibernating Virginia big-eared bats on a cave ceilingPhoto: Stihler Craig, U.S. Fish and Wildlife Service · Public domainVirginia big-eared bat hanging from a stone wallPhoto: Pinnacles National Park · CC BY 4.0Townsend's big-eared bat roosting in a rocky crevice

Townsend's Big-eared Bat in Montana, by the numbers

Rare in Montana 84th most recorded of 122 mammals logged in Montana

160 occurrence records

Records from 2000–2026.

When to look for the Townsend's Big-eared Bat in Montana

Most sightings fall in July to August.

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

Monthly Montana records (table)

Month	Records
January	1
February	2
March	5
April	2
May	5
June	5
July	65
August	61
September	10
October	2
November	0
December	2

Monthly townsend's big-eared bat occurrence records (iNaturalist and GBIF) in Montana, 2000–2026.

Seasonality

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

Occurrence map

Where Townsend's Big-eared Bat has been recorded in Montana

160 records mapped · zoom and drag to explore

160 Montana records mapped

Notable places to look

Park, forest, or monument	iNaturalist records
Lewis and Clark Caverns State Park	55
Isaac Homestead Wildlife Management Area	1
Kootenai National Forest	1

Protected places with the most townsend's big-eared 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 Montana

County	Records
Jefferson County	69
Fergus County	61
Ravalli County	8
Madison County	5
Musselshell County	4
Lake County	2
Big Horn County	2
Beaverhead County	2
Treasure County	1
Lincoln County	1
McCone County	1
Mineral County	1
3 other counties	3

The complete county distribution, spread across 15 Montana counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

Townsend’s big-eared bat is a cave- and mine-roosting specialist, and its 160 Montana records cluster around Glacier National Park, the Upper Missouri River Breaks, and Custer-Gallatin National Forest, rugged country with the cliff faces, caves, and abandoned mine workings this bat depends on for roosting and hibernation.

Reports climb sharply in July and August, when maternity colonies are most active and easiest to survey, then fall off fast by fall. NatureServe ranks the species S3, Vulnerable, in Montana, reflecting how few suitable roost sites remain and how vulnerable a colony is to a single cave disturbance.

Occurrence data from iNaturalist and GBIF.

Full species profile Townsend's Big-eared Bat Corynorhinus townsendii Size 5.8 cm2.3 in Weight 9–11 g0.3–0.4 oz Lifespan 16 yr View the full profile

More mammals in Montana 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"