Grizzly bears are a North American brown bear subspecies, recognized for their size, strength, and intelligence. They are considered an umbrella species, meaning their protection benefits many other species within their ecosystem. These omnivores play a role in their habitats by dispersing seeds and aerating soil, which improves plant diversity and soil health. While historically widespread across the western United States, their presence today is concentrated in specific regions.
Current Strongholds in the Lower 48 States
In the contiguous United States, grizzly bears are primarily found in isolated populations within the northern Rocky Mountains, designated as recovery zones under the Endangered Species Act (ESA). The Greater Yellowstone Ecosystem (GYE) is a significant stronghold, encompassing Yellowstone and Grand Teton National Parks and surrounding national forests in Wyoming, Montana, and Idaho. The GYE grizzly population has grown from 136 bears in 1975 to an estimated 1,030 in 2024.
The Northern Continental Divide Ecosystem (NCDE) is a major population center, located primarily in northwestern Montana and extending into Canada. This ecosystem includes Glacier National Park and surrounding wilderness areas, supporting over 1,000 grizzlies, making it the largest population in the lower 48 states.
Smaller, more vulnerable populations exist in other recovery zones. The Cabinet-Yaak Ecosystem (CYE) spans northwestern Montana and northern Idaho, bisected by the Kootenai River, with an estimated 50-55 grizzlies. The Selkirk Mountains, located in northern Idaho and northeastern Washington, also host a small transboundary population, estimated at 50-60 bears.
The North Cascades Ecosystem in north-central Washington, extending into British Columbia, represents another designated recovery zone. This population is very small, with estimates suggesting fewer than ten grizzlies remain in the U.S. portion, despite the area having substantial suitable habitat.
Grizzly Bears in Alaska
Unlike the fragmented populations in the lower 48 states, Alaska harbors a robust and widespread grizzly bear population. Grizzly bears, often referred to as brown bears in coastal Alaska, are found across most of the state, inhabiting diverse environments. Their abundance in Alaska means they are not considered endangered there, differentiating their status from those in the contiguous United States.
Kodiak Island, part of the Kodiak Archipelago in southwest Alaska, is renowned for its large Kodiak brown bears, a distinct subspecies. These bears thrive due to abundant food sources, especially salmon, and are estimated to number around 3,500 on the archipelago. Denali National Park is another vast wilderness area where grizzly bears roam freely, preying on large animals like moose and elk calves.
Understanding Their Range Decline
Historically, grizzly bears roamed across western North America, from Alaska to Mexico and the Pacific Coast to the Great Plains. Before 1800, an estimated 50,000 grizzly bears lived in portions of 18 western states. Their numbers dramatically declined to fewer than 1,000 in the lower 48 states by the mid-20th century, occupying only about two percent of their former range.
This decline was largely due to human activities. European settlers viewed grizzlies as threats, leading to widespread persecution including shooting, poisoning, and trapping. Habitat loss and fragmentation also played a role as human settlements and infrastructure developed. Legal protection under the Endangered Species Act (ESA) in 1975 halted their rapid decline and facilitated recovery efforts.