Wildlife is as diverse as the vegetative cover. In the alpine tundra, the snowpack does not melt until well into summer and plantlife is sparse. Several species have adapted to the harsh climate, including Mountain Goat, Gyrfalcon, White-tailed and Willow Ptarmigan, Water Pipit and Rosy Finch. Mule Deer, Rocky Mountain Elk, Stone Sheep, Grizzly Bear and Black Bear are common in lush meadow habitats and the stunted spruce groves known as krummholz.

Throughout the middle and upper elevations ungulates such as Mountain Goat, Moose, Caribou and Mule Deer are common. Rocky Mountain Elk, Bighorn Sheep, White-tailed Deer and Stone Sheep are found less frequently. Grizzly Bear and Black Bear are the most common large mammals. The conifer forests are also important habitat for fur-bearers such as Marten, Fisher, Red Squirrel and Wolverine and a diverse collection of birds that feed on conifer seeds, bark insects and small mammals. Common birds include Pileated Woodpecker, Northern Flicker, Clark's Nutcracker and Red Cross-bill.

Ponderosa Pine parklands provide habitat for species that forage on large conifer seeds (Clark's Nutcracker, Pygmy Nuthatch and Yellow-pine Chipmunk), bark insects (Northern Flicker and White-headed Woodpecker) or flying insects (Common Poorwill). The open forest canopy passes sufficient light for the production of shrubs palatable to wintering ungulates (Mule Deer and White-tailed Deer). Dense stands of Douglas Fir and Ponderosa Pine, meanwhile, provide a warm cover for wintering ungulates and an abundant seed and insect source for a variety of birds, small mammals, and coyotes.

The treeless bunchgrass areas are small relative to the adjacent forests, but they have an abundance and diversity of wildlife. This is partly due to the wide range of habitats created by the juxtaposition of grasslands, shrublands, wetlands and forest. The grasslands also represent a northern extension of the intermontane steppe of the western Great Basin in the south. Southern species such as Pallid Bat, Burrowing Owl and Short-horned Lizard reach their northern breeding limit here. On the other hand, northern species that rarely move further south, such as Snowy Owl and Gyrfalcon, can be found on open rangelands in winter.

Encroachment and pressures of development on the grasslands and lower slopes of many of the valleys within this ecozone have led to the destruction of habitat for many indigenous species. In 1995, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) listed seven mammals that inhabit this ecozone as vulnerable. COSEWIC also lists 10 bird species as either vulnerable or threatened and four -- Mountain Plover, Sage Thrasher, Burrowing Owl and Peregrine Falcon (anatum) -- as endangered. Four fish species and seven plants are also listed by COSEWIC.