Mammals of Yellowstone National Park: Complete Checklist

Yellowstone hosts 67 mammal species — the largest concentration in the lower 48 states. Categorized by size/visibility:

Large Mammals (Charismatic Megafauna)

• American Bison (~4,500; only continuously wild herd in US)
• Elk (Wapiti) (~10,000–20,000; summer)
• Grizzly Bear (~150–200 in GYE; threatened)
• Black Bear (common, lower elevations)
• Gray Wolf (~100 in park; reintroduced 1995)
• Cougar (Mountain Lion) (elusive, ~25–30)
• Moose (~200; declining, willow-dependent)
• Pronghorn (~500; fastest land mammal in Americas)
• Bighorn Sheep (~300; cliffs)
• Mule Deer / White-tailed Deer

Medium Mammals

• Coyote (ubiquitous, vocal)
• Red Fox (common, crepuscular)
• Bobcat (secretive)
• Canada Lynx (rare, threatened, high elevation)
• Wolverine (extremely rare, >10, GYE)
• River Otter (waterways)
• Badger (fossorial)
• Porcupine
• Beaver (ecosystem engineers)
• Marmot (Yellow-bellied) (alpine talus)

Small Mammals

• Pika (alpine, climate indicator)
• Chipmunks (Least, Uinta, Yellow-pine)
• Ground Squirrels (Golden-mantled, Uinta, Thirteen-lined)
• Tree Squirrels (Red, Northern Flying)
• Voles, Mice, Shrews, Pocket Gophers (abundant, base of food web)
• Snowshoe Hare (boreal forest)
• Muskrat (wetlands)

Bats (13 Species)

• Little Brown Myotis, Big Brown Bat, Hoary Bat, Silver-haired Bat, Long-eared Myotis, Long-legged Myotis, Townsend's Big-eared Bat, Fringed Myotis, Yuma Myotis, California Myotis, Western Small-footed Myotis, Pallid Bat, Spotted Bat.

Viewing Tips

• Dawn/Dusk = peak activity.
• Lamar & Hayden Valleys = wolf, bear, bison, elk.
• Mammoth/Gardiner = elk, pronghorn, bighorn.
• Boardwalks (Old Faithful, Grand Prismatic) = bear safety: carry spray, 100 yd distance.
• Never feed/approach. 25 yd (elk/bison), 100 yd (bears/wolves).