Wyoming is defined by its sprawling, high-altitude landscapes. This environment includes towering mountain ranges, vast high-desert plains, and pristine river systems. The state’s low human population density leaves expansive habitats undisturbed, supporting a rich diversity of animal life. This environment offers excellent opportunities for viewing large, free-ranging wildlife. This exploration details the major groups of animals that thrive across Wyoming’s unique and varied ecosystems.
Wyoming’s Iconic Large Mammals
Wyoming is famous for its megafauna, particularly large herds of grazing ungulates. The American Bison, Wyoming’s official state mammal, roams in large herds, notably within Yellowstone and Grand Teton National Parks, with males weighing up to 2,000 pounds. Massive herds of Elk, estimated around 110,000 animals, utilize forested areas in summer and congregate in valleys for winter.
The Pronghorn is the fastest land animal in North America, reaching speeds near 60 miles per hour across the open sagebrush steppe. These animals undertake long-distance migrations, traveling up to 150 miles one way between summer and winter ranges. Moose prefer specialized habitats, such as willow-lined river corridors and high-altitude forests like those in the Bridger-Teton National Forest.
Wyoming is also a stronghold for several large predators that maintain ecosystem balance. Gray Wolves were successfully reintroduced to the Yellowstone ecosystem in the mid-1990s and have thrived, exceeding recovery goals. Grizzly Bears are concentrated in the northwestern mountains as part of the recovered Greater Yellowstone Ecosystem population. The smaller American Black Bear is more widely distributed across the state’s forests.
Diverse Avian Populations
Wyoming supports a wide array of bird species, from raptors to upland birds. Two species of eagles are prominent. The Bald Eagle nests along major river systems like the Snake and Green Rivers. The Golden Eagle uses Wyoming as a nesting and wintering ground, though populations face challenges due to habitat loss and lead poisoning.
The Greater Sage-Grouse is tied directly to the vast sagebrush steppe habitat. Each spring, males gather at communal breeding grounds called leks to perform a courtship display, inflating specialized yellow air sacs to create popping sounds. Other large birds, including the Greater Sandhill Crane and the Trumpeter Swan, are found near wetlands and riparian areas. The Trumpeter Swan utilizes the Snake and Green River drainages.
Aquatic and Smaller Terrestrial Species
The state’s cold, clean waters are home to native fish, most notably the Yellowstone Cutthroat Trout. This species is distinguished by a red slash beneath its jaw and is native to the Yellowstone and Snake River watersheds. Its historical range has been reduced by the introduction of non-native fish species. The Cutthroat Trout is a keystone species, serving as a major food source for many birds and mammals.
On the prairies, the Black-tailed Prairie Dog is recognized as a keystone species due to the profound impact its colonies have on the ecosystem. Their extensive burrow systems provide shelter for numerous other animals, including the endangered Black-footed Ferret and Burrowing Owls. The Prairie Rattlesnake is the most common venomous snake, found across the eastern and central plains, and frequently utilizes abandoned prairie dog burrows for hibernation.
Beavers are small mammals that act as ecosystem engineers through their dam-building activities. Their dams create ponds that slow water flow, enhancing water retention and creating riparian wetlands that support 80 percent of Wyoming’s wildlife species. Beavers are actively relocated to damaged streams to aid in wetland restoration. Jackrabbits are common on the open plains and provide a food source for predators like eagles and coyotes.
Key Ecosystems and Wildlife Habitats
The distribution of Wyoming’s wildlife is linked to its major ecological zones, which remain largely intact due to expansive public lands. The Sagebrush Steppe covers the majority of the Wyoming Basin. This semi-arid zone is dominated by sagebrush and grasses, providing fundamental habitat for Pronghorn, Sage-Grouse, and other species adapted to its open conditions.
The Alpine and Mountain Ecosystems, including the Teton and Wind River Ranges, feature steep terrain and high elevations. These areas support animals like the Bighorn Sheep, Mountain Goats, and Pikas. They are characterized by coniferous forests at lower elevations and alpine tundra above the treeline.
The state’s River Corridors and Wetlands, though small in total area, are important because they provide water and rich riparian habitat. These river systems, including the headwaters of the Missouri, Colorado, and Columbia rivers, are sanctuaries for fish, waterfowl, and mammals like the Moose and Beaver. Wyoming’s vast, undeveloped landmass, with its low human population density, is the overarching factor that allows for the long-distance migrations and large population sizes of its wildlife.