Caribou, often known as reindeer in Eurasia, are a single species of deer (Rangifer tarandus) with a wide distribution across the northern reaches of the globe. These unique ungulates have adapted to survive in harsh, cold environments, from the Arctic tundra to boreal forests. While they remain widespread in North America, many southern populations have faced significant declines. This raises the question of whether any of these iconic animals still roam the mountains and forests of Wyoming.
The Current Status of Caribou in Wyoming
Caribou are no longer found within the state of Wyoming, having been locally extinct, or extirpated, for many decades. The last confirmed presence of a caribou population in the contiguous United States was the South Selkirk herd, which became functionally extinct in 2019, marking the species’ disappearance from the lower 48 states. Although the extirpation date for Wyoming specifically is less clear, the population’s decline likely culminated in the early 20th century.
The species is listed under the U.S. Endangered Species Act, specifically the Southern Mountain Caribou distinct population segment. This listing recognizes the precarious status of the remaining populations, which are now confined to Canada. Wyoming currently hosts no native, wild caribou populations; any caribou present are likely part of a non-native, domesticated herd, such as those used for holiday displays.
Historical Range and the Subspecies
The caribou that once inhabited Wyoming were part of the Woodland Caribou subspecies (Rangifer tarandus caribou), specifically the Southern Mountain Caribou ecotype. This ecotype is characterized by its adaptation to steep, mountainous terrain and a reliance on arboreal lichens, which grow on old-growth trees, as a primary winter food source. Their historical presence was concentrated in the northwestern region of the state, especially the high-elevation forests of the Teton Range.
These animals were at the southernmost edge of their range, extending into Idaho and possibly the far northwest of Wyoming. They used the deep snowpack of the subalpine zone to their advantage, climbing to high ridges to graze on tree lichens where the snow provided a barrier against predators. The Caribou-Targhee National Forest, whose name hints at the species’ former presence, covers the west slope of the Teton Range, marking the likely boundary of their historical habitat.
Factors Leading to Extirpation
The disappearance of caribou from Wyoming resulted from human-driven factors. Unregulated hunting by early settlers, miners, and native hunters using new firearms played a significant role in rapidly reducing caribou numbers. Since caribou are easier to locate and harvest than other ungulates, they were particularly vulnerable to increased hunting pressure.
Habitat fragmentation was a major cause, primarily through logging, mining, and road construction. Caribou depend on vast, undisturbed old-growth forests for their winter food source of arboreal lichens. Logging and development destroyed this specialized habitat, creating clearings that encouraged vegetation favored by other ungulates. This shift led to “apparent competition,” where the increased density of other prey species attracted a higher concentration of predators, such as wolves and cougars. Because caribou occur at low densities and have a slow reproductive rate, they became frequent, incidental prey, driving their reduced populations toward extirpation.