Currently, no caribou remain in Washington State, as the species has been functionally extirpated from the contiguous United States. The caribou that once roamed the state belonged to the Southern Mountain Caribou, an ecotype of the larger woodland caribou subspecies (Rangifer tarandus caribou). These animals were part of the southernmost herd in North America and were uniquely adapted to the inland temperate rainforest environment of the Pacific Northwest. Their disappearance represents a significant loss of biodiversity.
The Historical Range in Washington
The historical presence of caribou in Washington was concentrated in the northeastern corner of the state, specifically within the Southern Selkirk Mountains. This herd was the only one that ranged into the lower 48 states, crossing the international border with British Columbia. Historically, the species was more widespread, with a range that extended across northern Idaho and as far south as the Salmon River.
These animals are referred to as “mountain caribou” because their survival depends on the high-elevation, old-growth forests of the Selkirks. Unlike other deer species that move to lower elevations in winter, caribou migrate upward to elevations above 4,000 feet, where deep snow is present. They use the consolidated snowpack as a platform to reach arboreal lichens, their primary winter food source, which grow on mature western red cedar and hemlock trees. In the late 1800s, the Selkirk population was estimated to number in the hundreds.
Current Status and Extirpation
The last remaining resident caribou of the South Selkirk herd were officially removed from the contiguous United States in January 2019, marking the functional extinction of the species in Washington. Canadian wildlife officials captured the final surviving member, a female, and transported her to a captive breeding facility in British Columbia. This action followed a decline in the herd, which dropped from 46 individuals in 2009 to just 12 by 2016.
The decline was caused by several interacting factors, with habitat changes playing a major role. Extensive logging and road construction fragmented the old-growth forests that provide the arboreal lichens caribou need for winter survival. This habitat disturbance also created favorable conditions for other ungulates, such as deer and moose, by increasing early successional forage. The resulting rise in prey species led to an increase in predators, including wolves and cougars, which began preying on the caribou.
The small population size made the herd vulnerable to mortality, including human disturbance from winter recreation and highway collisions. Despite being listed as an endangered species under the U.S. Endangered Species Act since 1984, conservation efforts were not sufficient to counteract the threats. The species remains a state endangered species in Washington, reflecting a commitment to recovery even after the animals were removed from the wild.
Cross-Border Conservation Efforts
Efforts to manage and potentially restore the caribou population continue through international and multi-agency cooperation. The goal is to re-establish a self-sustaining population within the Selkirk recovery area, which encompasses portions of Washington, Idaho, and British Columbia. This work involves the U.S. Fish and Wildlife Service, Canadian environmental agencies, and local Native American Tribes, such as the Kalispel Tribe.
The last remaining caribou were moved to a captive breeding program in Canada to preserve the unique genetics of the Southern Mountain Caribou ecotype. Past augmentation efforts, involving translocating over 100 caribou from healthier Canadian herds in the late 1980s and 1990s, temporarily boosted numbers but did not lead to long-term stability. Current discussions focus on stabilizing the larger subpopulations in British Columbia, which may eventually provide a source for new translocations into the historic U.S. range. The Kalispel Tribe is working with Canadian partners to identify suitable source populations for a potential reintroduction.