There are at least 50 small mammal species known to occur in Yellowstone National Park.

Species are listed by common name, scientific name, typical habitat and relative abundance.^[1]

Raccoons

Order: Carnivora Family: Procyonidae

• Raccoon, Procyon lotor, rivers, cottonwoods, rare

Badgers and weasels

Order: Carnivora Family: Mustelidae

• Wolverine, Gulo gulo, alpine, coniferous forests, rare
• North American river otter, Lontra canadensis, rivers, lakes, ponds, common
• Pacific marten, Martes caurina, coniferous forests, common
• American ermine, Mustela richardsonii, willows to spruce/fir forests, common
• Long-tailed weasel, Neogale frenata, willows to spruce/fir forests, common
• American mink, Neogale vison, riparian forests, occasional
• Fisher, Pekania pennanti, forests, rare
• American badger, Taxidea taxus, sagebrush, common

Skunks

Order: Carnivora Family: Mephitidae

• Striped skunk, Mephitis mephitis, riparian to forest, rare

Hares and rabbits

Order: Lagomorpha Family: Leporidae

• Snowshoe hare, Lepus americanus, forests, willows, common
• White-tailed jackrabbit, Lepus townsendii, sagebrush, grasslands, common
• Desert cottontail, Sylvilagus audubonii, shrub lands, common
• Mountain cottontail, Sylvilagus nuttallii, shrub lands, common

Pikas

Order: Lagomorpha Family: Ochotonidae

• American pika, Ochotona princeps, rocky slopes, common

Shrews

Order: Soricomorpha Family: Soricidae

• Dusky shrew, Sorex monticolus, moist meadows, forests, common
• Masked shrew, Sorex cinereus, moist meadows, forests, common
• American water shrew, Sorex palustris, moist meadows, forests, common
• Preble's shrew, Sorex preblei, moist meadows, forests, rare, if present
• Dwarf shrew, Sorex nanus, moist meadows, forests, rare

Beaver

Order: Rodentia Family: Castoridae

• Beaver, Castor canadensis, ponds, streams, approximately 500

Squirrels

Order: Rodentia Family: Sciuridae

• Least chipmunk, Tamias minimus, forests, common
• Uinta chipmunk, Tamias umbrinus, forests, common
• Yellow-pine chipmunk, Tamias amoenus, forests, common
• Yellow-bellied marmot, Marmota flaviventris, rocky slopes, common
• Golden-mantled ground squirrel, Callospermophilus lateralis, forests, rocky slopes, common
• Northern flying squirrel, Glaucomys sabrinus, forests, occasional
• American red squirrel, Tamiasciurus hudsonicus, forests, common
• Uinta ground squirrel, Urocitellus armatus, sagebrush, meadows, common

Pocket gophers

Order: Rodentia Family: Geomyidae

• Northern pocket gopher, Thomomys talpoides, sagebrush, meadows, forests, common

Mice

Order: Rodentia Family: Cricetidae

• Deer mouse, Peromyscus maniculatus, grasslands, common

Jumping mice

Order: Rodentia Family: Dipodidae

• Western jumping mouse, Zapus princeps, riparian, occasional

Muskrats, voles and woodrats

Order: Rodentia Family: Cricetidae

• Muskrat, Ondatra zibethicus, streams, lakes, ponds, common
• Western heather vole, Phenacomys intermedius, sagebrush to forests, occasional
• Long-tailed vole, Microtus longicaudus, moist meadows, common
• Meadow vole, Microtus pennsylvanicus, moist meadows, common
• Montane vole, Microtus montanus, moist meadows, common
• Southern red-backed vole, Myodes gapperi, dense forests, common
• Water vole, Microtus richardsoni, riparian, occasional
• Bushy-tailed woodrat, Neotoma cinerea, rocky slopes, common

Porcupines

Order: Rodentia Family: Erethizontidae

• North American porcupine, Erethizon dorsatum, forests, sagebrush, willows, common

Bats

Order: Chiroptera Family: Vespertilionidae

• Big brown bat, Eptesicus fuscus, roost in sheltered areas, common
• Fringe-tailed bat, Myotis thysanodes, roost in cliffs, large snags, uncommon
• Hoary bat, Lasiurus cinereus, roost in trees. uncommon
• Little brown bat, Myotis lucifugus, roost in caves, buildings, trees, common
• Long-eared bat, Myotis evotis, roost in cliffs, buildings, uncommon
• Long-legged bat, Myotis volans, roost in tree cavities, cliffs, buildings, common
• Silver-haired bat, Lasionycteris noctivagans, roost in trees, including snags, common
• Western small-footed bat, Myotis ciliolabrum, roost in rocky areas, caves, rare, if present
• Townsend's big-eared bat, Corynorhinus townsendii, roost in caves, uncommon
• Yuma bat, Myotis yumanensis, roost in caves, buildings, trees. rare, if present