Mammals of Montana

97 established wild species in Montana. Plus 16 range-listed species with few or no digitized records.

All species A-Z →

AmericanBadger

American Badger

Taxidea taxus

Common in Montana 145 sightings
Size 63.9 cm2.1 ft Weight 4–12 kg8.8–26.5 lb active by night grassland

Sightings by month

Beaver swimming low in murky green pond water with only its wet head and back above the surface

American Beaver

Castor canadensis

Common in Montana 503 sightings
Size 60–90 cm2–3 ft Weight 11–32 kg24.3–70.5 lb active day & night river

Sightings by month

Image-American bison rests at hot spring in yellowstone national park 1

American Bison

Bison bison

Common in Montana 1,322 sightings
Size 1.9–2 m6.1–6.6 ft Weight 360–1000 kg793.7–2204.6 lb active day & night grassland

Sightings by month

Oso negro (Ursus americanus), Parque natural provincial Tatshenshini-Alsek, Yukón, Canadá, 2017-08-25, DD 85

American Black Bear

Ursus americanus

Common in Montana 1,347 sightings
Size 1.2–2 m3.9–6.6 ft Weight 40–250 kg88.2–551.2 lb active by night conifer forest

Sightings by month

Mustela Erminea head

American Ermine

Mustela erminea

Occasional in Montana 28 sightings
Size 17–33 cm6.7–13 in Weight 70–260 g2.5–9.2 oz active by night coniferous forest

Sightings by month

Marten in a tree

American marten

Martes americana

Occasional in Montana 25 sightings
Size 32–45 cm12.6–17.7 in Weight 0.5–1.4 kg1.1–3.1 lb active by night lake

Sightings by month

Norka amerykańska (neovison vison)

American Mink

Neogale vison

Occasional in Montana 108 sightings
Size 33–45.7 cm13–18 in Weight 0.5–1.4 kg1–3 lb active day & night lake

Sightings by month

American pika perched on a talus rock with a mouthful of alpine wildflowers

American Pika

Ochotona princeps

Common in Montana 305 sightings
Size 19 cm7.5 in Weight 140 g4.9 oz active day & night rocky outcrop

Sightings by month

American pygmy shrew crossing an asphalt path

American pygmy shrew

Sorex hoyi

Occasional in Montana 94 sightings
Size 5–7 cm2–2.8 in Weight 2–5 g0.1–0.2 oz active day & night deciduous forest

Sightings by month

Tamiasciurus hudsonicus James Gardens

American Red Squirrel

Tamiasciurus hudsonicus

Common in Montana 1,264 sightings
Size 17–23 cm6.7–9.1 in Weight 140–310 g4.9–10.9 oz active by day wetland

Sightings by month

American water shrew swimming at the surface of a stream, seen from above

American water shrew

Sorex palustris

Common in Montana 210 sightings
Size 8 cm3.1 in Weight 8–18 g0.3–0.6 oz active day & night river

Sightings by month

Sorex arcticus

Arctic shrew

Sorex arcticus

Rarely seen in Montana 13 sightings
Size 10–13 cm3.9–5.1 in Weight 5–11 g0.2–0.4 oz active by night boreal forest

Sightings by month

Big Brown Bats (Eptesicus fuscus)

Big Brown Bat

Eptesicus fuscus

Occasional in Montana 24 sightings
Size 7.5 cm3 in Weight 17 g0.6 oz active by night agricultural

Sightings by month

New Mexico Bighorn Sheep

Bighorn Sheep

Ovis canadensis

Common in Montana 2,047 sightings
Size 1.7 m5.5 ft Weight 58–143 kg127.9–315.3 lb active day & night desert

Sightings by month

Black-footed ferret checking out his new digs (30027077935)

Black-footed Ferret

Mustela nigripes

Rarely seen in Montana 5 sightings
Size 38–50 cm15–19.7 in Weight 0.7–1.2 kg1.4–2.6 lb active by night great basin desert

Sightings by month

Black-tailed jackrabbit (6785302534)

Black-tailed Jackrabbit

Lepus californicus

Rarely seen in Montana 10 sightings
Size 47–63 cm1.5–2.1 ft Weight 1.3–3.6 kg2.9–7.9 lb active by night open desert

Sightings by month

black-tailed prairie dog (Cynomys ludovicianus)

Black-tailed Prairie Dog

Cynomys ludovicianus

Common in Montana 355 sightings
Size 28–36 cm11–14.2 in Weight 0.7–1.5 kg1.5–3.3 lb active by day grassland

Sightings by month

Bobcat (Lynx rufus)

Bobcat

Lynx rufus

Common in Montana 206 sightings
Size 30–60 cm11.8–23.6 in Weight 4–18 kg8.8–39.7 lb active by night forest edge

Sightings by month

Grizzly brown bear standing in a green meadow in Yellowstone National Park

Brown Bear

Ursus arctos

Common in Montana 663 sightings
Size 1–2.8 m3.3–9.2 ft Weight 130–700 kg286.6–1543.2 lb active day & night forest

Sightings by month

Bushy-tailed woodrat peering from forest floor cover at Oregon Caves

Bushy-tailed Woodrat

Neotoma cinerea

Occasional in Montana 82 sightings
Size 22.7 cm8.9 in Weight 286 g10.1 oz active by night coniferous forest

Sightings by month

California Myotis (Myotis californicus)

California Myotis

Myotis californicus

Rarely seen in Montana 19 sightings
Size 3–3.5 cm1.2–1.4 in Weight 4 g0.1 oz active by night coastal

Sightings by month

Lynx Canadensis

Canada Lynx

Lynx canadensis

Occasional in Montana 35 sightings
Size 48–56 cm18.9–22 in Weight 5–17 kg11–37.5 lb active by night coniferous forest

Sightings by month

Columbian ground squirrel Urocitellus columbianus

Columbian Ground Squirrel

Urocitellus columbianus

Common in Montana 1,933 sightings
Size 33–41 cm13–16.1 in Weight 350–800 g0.8–1.8 lb active by day montane meadow

Sightings by month

Common golden-mantled ground squirrel on a fallen log, showing its plain face and striped sides

Common Golden-mantled Ground Squirrel

Callospermophilus lateralis

Common in Montana 1,102 sightings
Size 23–32 cm9.1–12.6 in Weight 120–350 g4.2–12.3 oz active by day chaparral

Sightings by month

Common Raccoon in Hugh Taylor Birch State Park

Common Raccoon

Procyon lotor

Common in Montana 223 sightings
Size 40–70 cm1.3–2.3 ft Weight 3.5–9 kg7.7–19.8 lb active by night mixed forest

Sightings by month

Mother Coyote Sitting, Watching Over Den, Photo 1 of 2 (47924154788)

Coyote

Canis latrans

Common in Montana 366 sightings
Size 0.8–1 m2.5–3.3 ft Weight 7–21 kg15.4–46.3 lb active day & night urban

Sightings by month

Desert cottontail rabbit (Sylvilagus audubonii) (5-13-11) patagonia lake, scc, az -01 (5720663856)

Desert Cottontail

Sylvilagus audubonii

Occasional in Montana 61 sightings
Size 35–43 cm13.8–16.9 in Weight 0.7–1.2 kg1.5–2.6 lb active day & night desert

Sightings by month

AI-generated image: Dwarf Shrew in side profile crossing rocky alpine gravel. No public-domain photograph of this species exists. This image was generated with AI from verified reference material and reviewed by our editorial team for accuracy

Dwarf Shrew

Sorex nanus

Occasional in Montana 29 sightings
Size 5.6 cm2.2 in Weight 2–3 g0.1 oz active day & night great basin desert

Sightings by month

Blacklick Woods - Eastern cottontail feeding 1

Eastern Cottontail

Sylvilagus floridanus

Marginal occurrence · 7 records
Size 36–43 cm14.2–16.9 in Weight 0.8–1.5 kg1.8–3.3 lb active day & night lake
Grey squirrel (Sciurus carolinensis) 01

Eastern Gray Squirrel

Sciurus carolinensis

Marginal occurrence · 4 records
Size 23–30 cm9.1–11.8 in Weight 400–710 g0.9–1.6 lb active by day wetland

Sightings by month

Eastern red bat roosting among green leaves, disguised as a dead leaf

Eastern Red Bat

Lasiurus borealis

Marginal occurrence · 3 records
Size 9.3–11.7 cm3.7–4.6 in Weight 7–13 g0.2–0.5 oz active by night desert

Sightings by month

Elk (Cervus canadensis)

Elk

Cervus canadensis

Common in Montana 1,629 sightings
Size 1.6–2.7 m5.2–8.9 ft Weight 178–497 kg392.4–1095.7 lb active day & night forest edge

Sightings by month

European rabbit feeding in dry vegetation

European Rabbit

Oryctolagus cuniculus

Occasional in Montana 57 sightings
Size 34–50 cm13.4–19.7 in Weight 1–2.5 kg2.2–5.5 lb active by night grassland

Sightings by month

Martes Pennanti

Fisher

Pekania pennanti

Marginal occurrence · 6 records
Size 75–95 cm2.5–3.1 ft Weight 3.5–6 kg7.7–13.2 lb active dawn & dusk wetland
Sciurus niger

Fox Squirrel

Sciurus niger

Common in Montana 537 sightings
Size 25.4–38.1 cm10–15 in Weight 804 g1.8 lb active by day river

Sightings by month

Fringed Myotis (Myotis thysanodes)

Fringed Myotis

Myotis thysanodes

Marginal occurrence · 7 records
Size 5.4 cm2.1 in Weight 9 g0.3 oz active by night desert
Silver-gray wolf walking along a gravel bank in Alaska

Gray Wolf

Canis lupus

Common in Montana 188 sightings
Size 1.1–1.6 m3.4–5.2 ft Weight 23–80 kg50.7–176.4 lb active day & night cave

Sightings by month

Great Basin Pocket Mouse peering out from beneath desert shrub leaves

Great Basin Pocket Mouse

Perognathus parvus

Marginal occurrence · 9 records
Size 8.2 cm3.2 in Weight 21–22 g0.7–0.8 oz active by night great basin desert

Sightings by month

Hispid pocket mouse standing on pale rocky ground at night

Hispid Pocket Mouse

Chaetodipus hispidus

Marginal occurrence · 3 records
Size 17–23 cm6.7–9.1 in Weight 30–47 g1.1–1.7 oz active by night river
Hoary marmot (Marmota caligata) - Flickr - brewbooks (3)

Hoary Marmot

Marmota caligata

Common in Montana 864 sightings
Size 62–82 cm2–2.7 ft Weight 3.5–10 kg7.7–22 lb active by day lake

Sightings by month

House mouse in dry plant litter

House Mouse

Mus musculus

Occasional in Montana 44 sightings
Size 5–10 cm2–3.9 in Weight 12–30 g0.4–1.1 oz active by night agricultural

Sightings by month

Taschenratte-Zion-National-Park

Idaho pocket gopher

Thomomys idahoensis

Occasional in Montana 38 sightings
Size 22.9 cm9 in Weight 101 g3.6 oz active by night savanna

Sightings by month

Least Chipmunk in natural habitat

Least Chipmunk

Neotamias minimus

Occasional in Montana 121 sightings
Size 10–11 cm3.9–4.3 in Weight 41–47 g1.4–1.7 oz active by day shrubland

Sightings by month

Least Weasel (Mustela nivalis)

Least Weasel

Mustela nivalis

Rarely seen in Montana 6 sightings
Size 26 cm10.2 in Weight 50 g1.8 oz active by night grassland

Sightings by month

Long-eared myotis peering over weathered wood

Long-eared Myotis

Myotis evotis

Rarely seen in Montana 5 sightings
Size 8.7–10 cm3.4–3.9 in Weight 7 g0.2 oz active by night shrubland

Sightings by month

Long-legged myotis roosting on tree bark with wings folded

Long-legged Myotis

Myotis volans

Occasional in Montana 73 sightings
Size 8.3–10.6 cm3.3–4.2 in Weight 6–10 g0.2–0.4 oz active by night urban

Sightings by month

Long-tailed vole peering from rocks

Long-tailed Vole

Microtus longicaudus

Occasional in Montana 50 sightings
Size 13.5 cm5.3 in Weight 50 g1.8 oz active day & night cave

Sightings by month

Long-tailed weasel standing alert in grass with its black-tipped tail curled behind it, Sonoma County, California

Long-tailed Weasel

Neogale frenata

Occasional in Montana 106 sightings
Size 24.8 cm9.8 in Weight 170 g6 oz active day & night wetland

Sightings by month

Sorex cinereus, Harwich, Chatham, Ontario, Canada 1

Masked Shrew

Sorex cinereus

Occasional in Montana 121 sightings
Size 6.9 cm2.7 in Weight 5 g0.2 oz active day & night grassland

Sightings by month

AI-generated image: Merriam's Shrew in side profile on dry soil among rocks. No public-domain photograph of this species exists. This image was generated with AI from verified reference material and reviewed by our editorial team for accuracy

Merriam's Shrew

Sorex merriami

Occasional in Montana 23 sightings
Size 6.2 cm2.4 in Weight 5 g0.2 oz active day & night desert

Sightings by month

AI-generated image: Montane Shrew in side profile on mossy forest floor. No public-domain photograph of this species exists. This image was generated with AI from verified reference material and reviewed by our editorial team for accuracy

Montane Shrew

Sorex monticolus

Common in Montana 345 sightings
Size 6.8 cm2.7 in Weight 6 g0.2 oz active day & night riparian

Sightings by month

Montane vole peering out from lichen-covered alpine rocks

Montane Vole

Microtus montanus

Common in Montana 371 sightings
Size 14–22 cm5.5–8.7 in Weight 35 g1.2 oz active day & night montane forest

Sightings by month

Cow moose standing in a marshy Alaska wetland

Moose

Alces alces

Common in Montana 1,462 sightings
Size 2.4–3.1 m7.9–10.2 ft Weight 200–490 kg440.9–1080.3 lb active day & night wetland

Sightings by month

Mountain cottontail in dry western woodland edge

Mountain Cottontail

Sylvilagus nuttallii

Common in Montana 483 sightings
Size 27.9–38.1 cm11–15 in Weight 0.6–1.1 kg1.3–2.4 lb active day & night coniferous forest

Sightings by month

Mountain goat standing on a rocky overlook above Hidden Lake in Glacier National Park with snow-streaked peaks behind

Mountain Goat

Oreamnos americanus

Common in Montana 1,865 sightings
Size 1.2–1.8 m3.9–5.9 ft Weight 45–140 kg99.2–308.6 lb active day & night subalpine

Sightings by month

Mountain Lion (Puma concolor)

Mountain Lion

Puma concolor

Common in Montana 153 sightings
Size 1–1.5 m3.3–5.1 ft Weight 36–120 kg79.4–264.6 lb active day & night montane forest

Sightings by month

Mule Deer (Odocoileus hemionus)

Mule Deer

Odocoileus hemionus

Common in Montana 2,018 sightings
Size 1.3–1.7 m4.1–5.5 ft Weight 55–150 kg121.3–330.7 lb active day & night river

Sightings by month

Muskrats resting on a floating log in open water

Muskrat

Ondatra zibethicus

Common in Montana 358 sightings
Size 25–36 cm9.8–14.2 in Weight 0.6–2 kg1.3–4.4 lb active day & night wetland

Sightings by month

Deer Mouse (Peromyscus maniculatus) (9310532204)

North American Deermouse

Peromyscus maniculatus

Common in Montana 3,395 sightings
Size 8–10 cm3.1–3.9 in Weight 21 g0.7 oz active by night river

Sightings by month

Erethizontidae Erethizon dorsatum 3.2

North American Porcupine

Erethizon dorsatus

Common in Montana 247 sightings
Size 60–90 cm2–3 ft Weight 3.5–12 kg7.7–26.5 lb active by night mixed forest

Sightings by month

River Otter (Lontra canadensis)

North American River Otter

Lontra canadensis

Occasional in Montana 65 sightings
Size 0.7–1.1 m2.2–3.5 ft Weight 5–15 kg11–33.1 lb active day & night river

Sightings by month

Illustration: northern bog lemmings (as Arvicola borealis) from John Woodhouse Audubon's 1845 Northern Meadow-Mouse plate

Northern Bog Lemming

Synaptomys borealis

Occasional in Montana 39 sightings
Size 13 cm5.1 in Weight 21 g0.7 oz active day & night wetland

Sightings by month

Northern Flying Squirrel (Glaucomys sabrinus)

Northern Flying Squirrel

Glaucomys sabrinus

Occasional in Montana 26 sightings
Size 25–37 cm9.8–14.6 in Weight 148 g5.2 oz active by night mixed conifer

Sightings by month

Northern grasshopper mouse walking beside desert grass

Northern Grasshopper Mouse

Onychomys leucogaster

Occasional in Montana 82 sightings
Size 12.7 cm5 in Weight 33 g1.2 oz active by night grassland

Sightings by month

Hoary bat in flight against blue sky, wings spread to show its yellow throat patch and heavily frosted fur

Northern Hoary Bat

Lasiurus cinereus

Rarely seen in Montana 7 sightings
Size 13–15 cm5.1–5.9 in Weight 26 g0.9 oz active by night cave

Sightings by month

Live northern montane shrew standing alert on sunlit sphagnum moss with dry grass stems around it

Northern Montane Shrew

Sorex obscurus

Marginal occurrence · 3 records
Size 7.6 cm3 in Weight 7 g0.2 oz active by night montane forest
Northern myotis hanging head-down from a rock ceiling, long ears and tan fur visible

Northern Myotis

Myotis septentrionalis

Range-listed · no digitized records yet
Size 8.6 cm3.4 in Weight 6 g0.2 oz active by night coniferous forest
Northern pocket gopher in low vegetation

Northern pocket gopher

Thomomys talpoides

Occasional in Montana 75 sightings
Size 22.9 cm9 in Weight 60–160 g2.1–5.6 oz active day & night river

Sightings by month

Northern Short-tailed Shrew (Blarina brevicauda)

Northern Short-tailed Shrew

Blarina brevicauda

Marginal occurrence · 1 record
Size 11.1 cm4.4 in Weight 21 g0.7 oz active day & night riparian
Live Norway rat beside shallow water

Norway Rat

Rattus norvegicus

Marginal occurrence · 4 records
Size 15–28 cm5.9–11 in Weight 140–500 g0.3–1.1 lb active by night urban
Olive-backed pocket mouse in grass and dry litter at night

Olive-backed Pocket Mouse

Perognathus fasciatus

Occasional in Montana 103 sightings
Size 8 cm3.1 in Weight 11–14 g0.4–0.5 oz active by night grassland

Sightings by month

Ord's kangaroo rat standing in profile, showing its huge hind feet and long tufted tail

Ord's Kangaroo Rat

Dipodomys ordii

Rarely seen in Montana 7 sightings
Size 21–36.5 cm8.3–14.4 in Weight 50 g1.8 oz active by night great basin desert

Sightings by month

Pacific Marten (Martes caurina)

Pacific Marten

Martes caurina

Occasional in Montana 34 sightings
Size 50–70 cm1.6–2.3 ft Weight 0.5–1.4 kg1.1–3.1 lb active by night coniferous forest

Sightings by month

Pallid bat roosting on a cave wall

Pallid Bat

Antrozous pallidus

Marginal occurrence · 4 records
Size 6–8.5 cm2.4–3.3 in Weight 14–25 g0.5–0.9 oz active by night desert scrub
AI-generated image: Prairie Shrew foraging in shortgrass prairie ground litter. No public-domain photograph of this species exists. This image was generated with AI from verified reference material and reviewed by our editorial team for accuracy.

Prairie Shrew

Sorex haydeni

Occasional in Montana 43 sightings
Size 7–10 cm2.8–3.9 in Weight 3–6 g0.1–0.2 oz active by night prairie

Sightings by month

AI-generated image: Prairie Vole alert in a grassy meadow, stocky grizzled brown-gray body and short tail. No public-domain photograph of this species exists. This image was generated with AI from verified reference material and reviewed by our editorial team for accuracy

Prairie Vole

Microtus ochrogaster

Common in Montana 167 sightings
Size 12.4 cm4.9 in Weight 47 g1.7 oz active day & night grassland

Sightings by month

AI-generated image: Preble's Shrew in side profile on dry soil among grass. No public-domain photograph of this species exists. This image was generated with AI from verified reference material and reviewed by our editorial team for accuracy

Preble's Shrew

Sorex preblei

Occasional in Montana 49 sightings
Size 5.5 cm2.2 in Weight 3 g0.1 oz active day & night great basin desert

Sightings by month

Pronghorn buck standing in a meadow of yellow wildflowers

Pronghorn

Antilocapra americana

Common in Montana 1,537 sightings
Size 1.2–1.5 m3.9–4.9 ft Weight 32–70 kg70.5–154.3 lb active day & night grassland

Sightings by month

Pygmy rabbit (22694681746)

Pygmy Rabbit

Sylvilagus idahoensis

Marginal occurrence · 15 records
Size 23.5–29.5 cm9.3–11.6 in Weight 375–500 g0.8–1.1 lb active day & night great basin desert
Red Fox (Vulpes vulpes)

Red Fox

Vulpes vulpes

Common in Montana 602 sightings
Size 43 cm16.9 in Weight 5–10 kg11–22 lb active day & night desert

Sightings by month

Red-tailed Chipmunk (Tamias ruficaudus)

Red-tailed Chipmunk

Neotamias ruficaudus

Occasional in Montana 44 sightings
Size 23–25 cm9.1–9.8 in Weight 48–62 g1.7–2.2 oz active by day coniferous forest

Sightings by month

Urocitellus richardsonii GNP 03

Richardson's Ground Squirrel

Urocitellus richardsonii

Common in Montana 314 sightings
Size 28–33 cm11–13 in Weight 250–610 g0.6–1.3 lb active by day prairie

Sightings by month

Sagebrush vole partly hidden in low shrub cover

Sagebrush Vole

Lemmiscus curtatus

Common in Montana 125 sightings
Size 11–14 cm4.3–5.5 in Weight 28 g1 oz active day & night shrubland

Sightings by month

Silver-haired bat tucked into loose bark

Silver-haired Bat

Lasionycteris noctivagans

Rarely seen in Montana 18 sightings
Size 9.5–11.5 cm3.7–4.5 in Weight 11 g0.4 oz active by night river

Sightings by month

Lepus americanus 5459 cropped

Snowshoe Hare

Lepus americanus

Common in Montana 276 sightings
Size 41–52 cm16.1–20.5 in Weight 1.4–1.6 kg3.2–3.4 lb active by night coniferous forest

Sightings by month

Southern red-backed vole feeding among sunflower seeds on snow

Southern Red-backed Vole

Clethrionomys gapperi

Rarely seen in Montana 14 sightings
Size 12–16.5 cm4.7–6.5 in Weight 6–42 g0.2–1.5 oz active by night mixed forest

Sightings by month

Live western jumping mouse crouched in leaf litter with its long tail curving behind

Southwestern Jumping Mouse

Zapus princeps

Common in Montana 722 sightings
Size 22–25 cm8.7–9.8 in Weight 28 g1 oz active by night montane forest

Sightings by month

Spotted bat facing forward with huge pale ears and white shoulder patches

Spotted Bat

Euderma maculatum

Marginal occurrence · 3 records
Size 12.6 cm5 in Weight 16–20 g0.6–0.7 oz active by night rocky outcrop

Sightings by month

Mephitis mephitis in Dierenpark Zie-ZOO

Striped Skunk

Mephitis mephitis

Common in Montana 144 sightings
Size 46.5–81.5 cm1.5–2.7 ft Weight 0.6–6.3 kg1.3–13.9 lb active by night grassland

Sightings by month

Swift fox at a burrow entrance on the shortgrass prairie

Swift Fox

Vulpes velox

Rarely seen in Montana 13 sightings
Size 38–53 cm15–20.9 in Weight 1.6–3 kg3.5–6.6 lb active day & night grassland

Sightings by month

Thirteen-lined ground squirrel crouched beside short grass

Thirteen-lined ground squirrel

Ictidomys tridecemlineatus

Occasional in Montana 24 sightings
Size 17–30 cm6.7–11.8 in Weight 173 g6.1 oz active by day grassland

Sightings by month

Townsend's big-eared bat roosting on a cave wall

Townsend's Big-eared Bat

Corynorhinus townsendii

Rarely seen in Montana 19 sightings
Size 5.8 cm2.3 in Weight 9–11 g0.3–0.4 oz active by night coastal

Sightings by month

Uinta Chipmunk in natural habitat

Uinta Chipmunk

Neotamias umbrinus

Occasional in Montana 68 sightings
Size 14.2 cm5.6 in Weight 52 g1.8 oz active by day montane forest

Sightings by month

Uinta ground squirrel (14952252050)

Uinta Ground Squirrel

Urocitellus armatus

Occasional in Montana 92 sightings
Size 28–30 cm11–11.8 in Weight 210 g7.4 oz active by day river

Sightings by month

Vagrant shrew crossing bare sandy ground

Vagrant Shrew

Sorex vagrans

Common in Montana 1,458 sightings
Size 6.8 cm2.7 in Weight 4–8 g0.1–0.3 oz active day & night montane forest

Sightings by month

Western deer mouse sheltering in a rock crevice

Western Deer Mouse

Peromyscus sonoriensis

Size 12–20 cm4.7–7.9 in Weight 15–32 g0.5–1.1 oz active by night river

Sightings by month

Western harvest mouse moving through dry stems and gravel

Western Harvest Mouse

Reithrodontomys megalotis

Occasional in Montana 72 sightings
Size 11.8–17 cm4.6–6.7 in Weight 11 g0.4 oz active by night wetland

Sightings by month

Western heather vole tucked among moss and wet alpine leaves

Western Heather Vole

Phenacomys intermedius

Occasional in Montana 76 sightings
Size 11.2 cm4.4 in Weight 40 g1.4 oz active day & night alpine

Sightings by month

Little brown myotis roosting alertly on a wooden beam

Western Little Brown Myotis

Myotis lucifugus

Rarely seen in Montana 12 sightings
Size 8–9.5 cm3.1–3.7 in Weight 6–13 g0.2–0.5 oz active by night cave

Sightings by month

Western meadow vole Talkeetna alaska

Western Meadow Vole

Microtus drummondii

Rarely seen in Montana 8 sightings
Size 13–20 cm5.1–7.9 in Weight 39 g1.4 oz active day & night river

Sightings by month

AI-generated image: Western Pygmy Shrew in side profile on mossy forest floor. No public-domain photograph of this species exists. This image was generated with AI from verified reference material and reviewed by our editorial team for accuracy

Western Pygmy Shrew

Sorex eximius

Range-listed · no digitized records yet
Size 5–7 cm2–2.8 in Weight 2–4 g0.1 oz active day & night montane conifer forest
Western small-footed myotis roosting on wood with its dark face mask visible

Western Small-footed Myotis

Myotis ciliolabrum

Rarely seen in Montana 4 sightings
Size 8–10 cm3.1–3.9 in Weight 4–5 g0.1–0.2 oz active by night desert

Sightings by month

Western spotted skunk with a clear broken-stripe pattern, alert on a branch at night

Western Spotted Skunk

Spilogale gracilis

Marginal occurrence · 6 records
Size 35–45 cm13.8–17.7 in Weight 336–734 g0.7–1.6 lb active by night mixed forest
Western water shrew at the grassy edge of a stream

Western Water Shrew

Sorex navigator

Common in Montana 210 sightings
Size 13–17 cm5.1–6.7 in Weight 13 g0.5 oz active day & night river

Sightings by month

White-footed mouse on a fallen log in leaf litter

White-footed Mouse

Peromyscus leucopus

Rarely seen in Montana 20 sightings
Size 10.1 cm4 in Weight 20–30 g0.7–1.1 oz active by night urban

Sightings by month

White-tailed Deer (Odocoileus virginianus)

White-tailed Deer

Odocoileus virginianus

Common in Montana 2,714 sightings
Size 0.9–2.2 m3.1–7.2 ft Weight 68–136 kg149.9–299.8 lb active day & night mixed forest

Sightings by month

White-tailed Jackrabbit (Lepus townsendii)

White-tailed Jackrabbit

Lepus townsendii

Occasional in Montana 82 sightings
Size 45–65 cm1.5–2.1 ft Weight 2.6–4.3 kg5.7–9.5 lb active by night grassland

Sightings by month

Whitetailedprairiedoghi

White-tailed Prairie Dog

Cynomys leucurus

Rarely seen in Montana 7 sightings
Size 30–37 cm11.8–14.6 in Weight 0.8–1.5 kg1.8–3.3 lb active by day grassland

Sightings by month

Wolverine (Gulo gulo)

Wolverine

Gulo gulo

Occasional in Montana 22 sightings
Size 17–26 cm6.7–10.2 in Weight 7–18 kg15.4–39.7 lb active by night urban

Sightings by month

Wyoming ground squirrel peering from a burrow entrance

Wyoming Ground Squirrel

Urocitellus elegans

Occasional in Montana 27 sightings
Size 19–24 cm7.5–9.4 in Weight 299 g10.5 oz active by day montane forest

Sightings by month

Marmota flaviventris (29862435206)

Yellow-bellied Marmot

Marmota flaviventris

Common in Montana 453 sightings
Size 47–68 cm1.5–2.2 ft Weight 3–5 kg6.6–11 lb active by day great basin desert

Sightings by month

Yellow-pine Chipmunk 2a wray (8272946686)

Yellow-pine Chipmunk

Neotamias amoenus

Common in Montana 135 sightings
Size 18.1–24.5 cm7.1–9.6 in Weight 30–70 g1.1–2.5 oz active by day grassland

Sightings by month

Yuma myotis crouched on the ground at night

Yuma Myotis

Myotis yumanensis

Occasional in Montana 101 sightings
Size 8.4–9.9 cm3.3–3.9 in Weight 6 g0.2 oz active by night coniferous forest

Sightings by month