Idaho’s wild landscapes no longer host native caribou. The species, once a part of the state’s natural heritage, has been extirpated from Idaho, marking the official end of their presence in the lower 48 states.
Caribou’s Historical Footprint in Idaho
Historically, woodland caribou inhabited northern Idaho. These animals were adapted to high-elevation, forested areas with deep snowfall, characteristic of the inland temperate rainforest. Their traditional range extended across the Idaho Panhandle, particularly within the Selkirk Mountains, and records indicate they were found as far south as the Clearwater River and potentially the Salmon River. Trapping records from the 1880s suggest caribou were once common in these northern Idaho regions.
By the 1950s, the caribou population in Idaho had dwindled to approximately 100 animals, primarily concentrated in the Selkirk Mountains. This small population was considered the southernmost group of woodland caribou in North America. These animals were known for their large, plate-like hooves, which acted like snowshoes, allowing them to navigate deep snow and access tree lichens, their primary winter food.
Factors Leading to Their Disappearance
Several factors contributed to the decline and eventual disappearance of caribou from Idaho. Habitat loss and fragmentation played a significant role, driven by extensive logging, road building, and large wildfires in the late 1800s and 1900s. This destruction of old-growth forests removed the mature trees that provided the lichens caribou depend on for sustenance. The altered landscape also led to changes in forest structure, which benefited other species like deer, elk, and moose.
The increase in these other ungulate populations, thriving in the changed habitats, subsequently attracted higher numbers of predators such as wolves and cougars. Caribou, which historically avoided predation by moving to high-elevation, deep-snow areas where other prey and predators did not venture, became more vulnerable. This shift in predator-prey dynamics, along with diseases like brainworm carried by deer, further reduced caribou numbers. Human disturbance, including increased snowmobiling access in winter habitat, also contributed to their stress and decline.
Current Status and Conservation Efforts
The last known caribou that roamed into the United States from the transboundary Selkirk Mountains herd were captured and relocated to a captive breeding facility in British Columbia in January 2019. This action officially marked the extirpation of the species from Idaho’s wild.
Despite earlier conservation attempts, the population continued to decline. Woodland caribou were listed as an endangered species in the U.S. in 1984, and critical habitat was designated in northern Idaho and northeastern Washington. Efforts included translocating caribou from British Columbia into the Selkirk Mountains between 1987 and 1990 to augment the herd. However, these augmentations did not lead to a sustained recovery. Challenges such as low reproductive rates, increased predation, and ongoing habitat changes ultimately prevented the re-establishment of a viable population.