61 different mammals
- Along with black bears over 500 grizzlies live in the greater Yellowstone ecosystem
- Gray wolves more than 370 live in the greater Yellowstone ecosystem. (Gray wolves were restored in 1995)
- Wolverine and Lynx live in the park and are some of the rarest mammals to spot.
- Seven native species of ungulates—elk, mule deer, bison, moose, bighorn sheep, pronghorn and white-tailed deer—live here, including one of the largest herds of elk in the United States.
- Non-native mountain goats have colonized the northwestern and northeastern portions of the park.