The grizzly bear, formally known as Ursus arctos horribilis, is an iconic North American mammal. This powerful bear is a subspecies of the brown bear, but its current distribution is a fraction of its historical presence. Its populations are now concentrated in specific, often isolated, strongholds. The location of the most grizzly bears is in areas that have retained expansive, wild habitat, particularly in the northern reaches of the continent.
Historical Perspective on Range Contraction
The historical range of the grizzly bear was immense, stretching from Alaska down to central Mexico and eastward across the Great Plains toward the western shores of Hudson Bay. Before European settlement, an estimated 50,000 grizzly bears roamed the contiguous United States alone, occupying all or parts of 18 western states. This vast territory included ecosystems from coastal rainforests to high alpine meadows and semi-arid plains.
The contraction of this range began in the 19th century with westward expansion and the growth of agriculture and ranching. Grizzlies were viewed as a threat to both human safety and economic interests, leading to widespread eradication efforts. By the time the species was listed as threatened in the contiguous United States in 1975, its population in the Lower 48 had plummeted to an estimated 700 to 800 bears. They were confined to roughly 2% of their original range, and this fragmentation isolated the remaining groups.
The Primary Global Concentrations: Alaska and Canada
The majority of the world’s grizzly bears are found in North America’s far north, where vast, undeveloped wilderness remains. The North American population is estimated to be around 60,000 bears, with over 50,000 residing in Alaska and Canada. These northern populations are largely continuous and less managed than those further south.
Alaska holds the single largest population, estimated at over 30,000 individuals. Grizzlies are widespread across the state, from the Arctic tundra to the coastal regions. Coastal areas support particularly dense populations due to the abundance of salmon. Notable concentrations include the coastal brown bears of the Alaska Peninsula and the large numbers found within Denali National Park and Preserve.
Canada serves as the other major stronghold, with an estimated population of up to 29,000 bears, primarily distributed across its western and northern territories. British Columbia is home to the largest number of grizzlies in Canada, with a 2012 estimate placing the population at approximately 15,075. Significant populations also thrive in the Yukon and the Northwest Territories. These robust northern populations maintain genetic diversity and connectivity across their ranges, contrasting sharply with the isolated groups to the south.
Key Ecosystems of the Lower 48 States
In the contiguous United States, the remaining grizzly bears survive in a few isolated ecosystems within the Northern Rocky Mountains. These populations are intensively monitored and managed as recovery zones under the Endangered Species Act. The two largest and most successful recovery areas are the Greater Yellowstone Ecosystem (GYE) and the Northern Continental Divide Ecosystem (NCDE).
The Greater Yellowstone Ecosystem, encompassing parts of Wyoming, Montana, and Idaho, supports the southernmost major population, with an estimated count of approximately 1,000 bears. This population, centered around Yellowstone and Grand Teton National Parks, has expanded its occupied range since its low point in the 1970s. However, this group remains genetically isolated, leading to management efforts like the translocation of bears from the NCDE to improve diversity.
North of Yellowstone is the Northern Continental Divide Ecosystem, which includes Glacier National Park and the Bob Marshall Wilderness Complex in Montana. This ecosystem also supports a population of around 1,000 bears. It is considered more stable because it maintains connectivity with the continuous Canadian population. The NCDE population has recently shown a significant expansion of its occupied range, pushing into new habitats on its eastern and southern boundaries.
Smaller populations exist in the Cabinet-Yaak and Selkirk Mountains ecosystems of northern Idaho and Montana, each supporting fewer than 100 bears. The North Cascades Ecosystem in Washington and the Bitterroot Ecosystem in Idaho and Montana are also designated recovery zones. They currently have extremely low or non-viable populations, with the North Cascades estimated to have fewer than 10 individuals. These groups highlight the fragmented nature of the species’ presence in the Lower 48, where conservation efforts are focused on maintaining small, distinct groups.