Grizzly bears once roamed from the Great Plains to the Pacific coast and from central Mexico well into Arctic Canada, but the map of where they live today is dramatically smaller and more fragmented. In the contiguous United States, grizzlies occupy roughly two percent of their historical range, clustered in five recognized populations spread across Montana, Wyoming, Idaho, and Washington. North of the border, the picture improves: grizzlies still inhabit large stretches of British Columbia, Alberta, the Yukon, the Northwest Territories, and Alaska, and they are increasingly showing up on Arctic islands where they were rarely seen a generation ago. Understanding the current map means understanding not just where bears are but how tenuously some of those populations are connected to one another.
The Two Big Populations in the Lower 48
Two grizzly bear populations in the contiguous United States anchor recovery efforts and contain the vast majority of bears south of the Canadian border. The Northern Continental Divide Ecosystem, centered on Glacier National Park and the Bob Marshall Wilderness Complex in Montana, holds an estimated population of over 1,000 grizzly bears and has been trending upward for years.1The Journal of Wildlife Management. Grizzly bear population vital rates and trend in the Northern Continental Divide Ecosystem, Montana This is the largest grizzly population in the lower 48, and its bears live across a mix of national forest, wilderness, tribal land, and private ranches.
The Greater Yellowstone Ecosystem, spanning portions of Wyoming, Montana, and Idaho around Yellowstone National Park, is the other major stronghold. The Yellowstone population is smaller and more geographically isolated, and genetic studies have detected a loss of genetic variability over time compared to other brown bear populations, though the decline has been less severe than some researchers initially feared.2PubMed Central. The history of effective population size and genetic diversity in the Yellowstone grizzly (Ursus arctos): implications for conservation The Yellowstone bears are effectively cut off from the Northern Continental Divide bears by hundreds of kilometers of developed land, highways, and private property. That separation has real consequences: without gene flow between the two populations, each one’s genetic health depends entirely on its own internal dynamics.
Three Smaller Populations Clinging On
Beyond the two large ecosystems, three much smaller grizzly populations exist in the northern tier of the lower 48. The Cabinet-Yaak Ecosystem straddles the Montana-Idaho border near the Canadian line, and the Selkirk Ecosystem sits in the mountains where Idaho, Washington, and British Columbia meet. Both are tiny. Effective population size estimates for the Selkirk, Yaak, and Cabinet segments range from roughly 6 to 18 breeding individuals, depending on the segment and the estimation method used.3Conservation Genetics. Gene flow prevents genetic diversity loss despite small effective population size in fragmented grizzly bear (Ursus arctos) populations Those are startlingly small numbers, and they mean that every individual bear matters for the population’s survival.
The bears in these small ecosystems are also physically distinct. Female grizzlies in the Cabinet-Yaak and Selkirk populations average about 94 kilograms of lean body mass, smaller than their counterparts in richer habitats. Researchers have linked this to their heavy reliance on huckleberries as a primary food source during summer and early fall, a diet that supports smaller-bodied bears but may not fuel the same growth seen in populations with access to abundant salmon or large ungulate carcasses.4PubMed Central. Huckleberry Habitat and Its Influence on Two Small Populations of Grizzly Bears (Ursus arctos)
The fifth recognized population area is the Bitterroot Ecosystem in central Idaho and western Montana. No resident grizzly bear population currently exists there; the bears were wiped out decades ago. But the Bitterroot has been evaluated for potential recovery through both natural recolonization from neighboring populations and active reintroduction. Researchers have used movement models from nearby bear populations to predict how grizzlies would use the Bitterroot landscape if they were reestablished, finding that suitable habitat exists.5PubMed Central. Predicting future grizzly bear habitat use in the Bitterroot Ecosystem under recolonization and reintroduction scenarios Whether bears will get there on their own or need human help remains an open policy question.
Canada and Alaska Hold the Bulk of the Range
If you zoom out from the lower 48, the picture changes. The majority of North America’s grizzly bears live in Canada and Alaska, where the species still occupies vast, relatively continuous habitat. British Columbia and Alberta together support tens of thousands of grizzlies across a range that stretches from the Rocky Mountain foothills through coastal rainforests. In Alberta, large-scale DNA-based inventories covering nearly 50,000 square kilometers found that bear density was highest in northern management areas with good habitat and lowest in southern areas where human-caused mortality risk was greatest.6PubMed Central. Using spatial mark-recapture for conservation monitoring of grizzly bear populations in Alberta
Alaska is the continent’s grizzly stronghold. Brown bears (the coastal term for the same species) occupy much of the state, from the dense salmon-rich forests of the southeast panhandle through the Alaska Range and out onto the tundra of the North Slope. Alaska’s bears benefit from vast tracts of public land with low human density and, in many areas, extraordinarily productive food sources like spawning salmon. In southeastern Alaska, brown bears function as one of the most important seed dispersers for fruit-bearing plants, eating large quantities of berries and excreting seeds in viable condition across the landscape.7The Canadian Field-Naturalist. Seed Dispersal by Brown Bears, Ursus arctos, in Southeastern Alaska The bears are not just occupying habitat; they are actively shaping the plant communities around them.
The Yukon and Northwest Territories round out the North American range, with grizzly bears living across boreal forest, mountain terrain, and increasingly, tundra environments. These northern populations are generally less studied than their southern counterparts, but they have attracted growing attention as bears push further north.
Pushing Into the Arctic
One of the most striking recent changes on the grizzly bear map is their expanding presence in the Arctic. Over the past couple of decades, grizzly bears have become noticeably more common on Arctic islands in Canada’s Inuvialuit Settlement Region, a shift that coincides with broader environmental change in the region. This northward push has brought grizzlies into contact with polar bears in ways that were once extremely rare, and confirmed grizzly-polar bear hybrids have been documented in the wild.8ARCTIC. Recent Hybridization between a Polar Bear and Grizzly Bears in the Canadian Arctic
The hybridization has sparked debate about what it means for both species. But grizzly range expansion in the subarctic has also created overlap with a third species: black bears. In parts of the Canadian subarctic, all three bear species now coexist in the same landscape, something that historically was uncommon. Researchers assessing the potential conservation effects of this three-way overlap concluded that the interactions are likely positive for grizzlies and weakly negative for black bears and polar bears, though the full picture is still emerging.9Arctic Science. Novel range overlap of three ursids in the Canadian subarctic The researchers cautioned against viewing this overlap as a threat to any of the three species, framing it instead as an ecological response to a changing environment that needs more study.
The Arctic expansion matters for the overall map because it represents one of the few places where grizzly range is actively growing rather than shrinking or staying static. While conservationists in the lower 48 are working to prevent further range contraction, the northern edge of the species’ range is creeping further into territory once dominated exclusively by polar bears.
Why Connectivity Between Populations Matters More Than Size
A dot on a map showing where bears live misses something critical: whether those bears can move between populations. For grizzlies in the lower 48 and southern Canada, connectivity is arguably the single biggest factor determining whether current populations will persist or slowly decline. Isolated populations, even large ones, face genetic erosion over time. Connected populations can exchange individuals, maintain genetic diversity, and recolonize areas after local losses.
The situation in the southern Canadian Rockies illustrates the problem. Genetic analysis has shown that a highway corridor and its associated settlements have effectively severed demographic connection between grizzly populations across their entire range in southern Canada. At least two of the resulting population fragments contain fewer than 100 animals, and one is completely isolated.10PubMed Central. Genetic analysis reveals demographic fragmentation of grizzly bears yielding vulnerably small populations These trans-border populations, which straddle the U.S.-Canada line, may be more threatened than their raw numbers suggest.
Even within Canada, grizzly bears alter their movements in response to human infrastructure. In the southern Canadian Rockies, bears avoided crossing highways but were attracted to areas alongside them where forage was otherwise scarce, creating a risky pattern of bears using road margins as feeding corridors. Females tended to avoid towns during spring and summer, while males were somewhat more willing to pass through developed areas. Researchers modeling future scenarios predicted that proposed mines and expanded settlements would further decrease connectivity on top of losses already caused by existing development.11Conservation Science and Practice. Changing grizzly bear space use and functional connectivity in response to human disturbance in the southern Canadian Rocky Mountains
In the U.S., the most important connectivity question is whether grizzly bears from the Northern Continental Divide can disperse south to reach the Yellowstone population, or vice versa. Studies mapping potential dispersal paths for male grizzlies have found that neighboring mountain ranges could serve as stepping stones, but landscape features and human infrastructure tend to concentrate those paths into narrow corridors.12Ecosphere. Potential paths for male‐mediated gene flow to and from an isolated grizzly bear population Think of it less like a broad highway for bears and more like a series of fragile bridges, each one vulnerable to a new subdivision, a road widening, or a policy change. Modeling work has suggested that linking the Yellowstone and Glacier park assemblages by protecting dispersal pathways could increase medium to large mammal species persistence time by a factor of roughly four compared to individual parks operating in isolation.13PubMed Central. Enhanced regional connectivity between western North American national parks will increase persistence of mammal species diversity
Genetic Health in Small Fragments
For the smallest grizzly populations on the current map, genetic viability is not an abstract concern. The Cabinet-Yaak and Selkirk populations exist at effective population sizes so low that random genetic drift and inbreeding are real risks. Recent genetic monitoring, however, has offered a cautious note of optimism. After management actions to facilitate gene flow, including the translocation of bears from other populations, researchers found that genetic diversity increased in the Selkirk and Cabinet segments, and relatedness decreased across all three small fragments.3Conservation Genetics. Gene flow prevents genetic diversity loss despite small effective population size in fragmented grizzly bear (Ursus arctos) populations Gene flow, whether natural or human-assisted, was maintaining or even boosting diversity. But the researchers also noted that effective population sizes remain very low, especially in the Cabinet segment, and that additional connectivity or augmentation may still be needed.
The Yellowstone population’s genetic story is different in scale but follows a similar theme. Compared to other brown bear populations worldwide, Yellowstone grizzlies have lower genetic variability, and studies of museum specimens collected over the past century confirmed that some variability has been lost. But the loss was less dramatic than early hypotheses predicted, suggesting that the population may have been somewhat genetically depauperate even before European settlement rather than having experienced a catastrophic modern crash.2PubMed Central. The history of effective population size and genetic diversity in the Yellowstone grizzly (Ursus arctos): implications for conservation The practical question for managers is whether the current level of diversity is enough to sustain a healthy population over the coming centuries without outside input.
Shifting Food Sources and Habitat Use
Where grizzly bears live on a map is partly determined by where they can find food, and those food sources are changing. In the Greater Yellowstone Ecosystem, whitebark pine seeds were historically a critical fall food source, fueling bears’ pre-hibernation weight gain. But whitebark pine has been declining across much of its range due to mountain pine beetle outbreaks and the fungal disease white pine blister rust. Grizzlies in Yellowstone have responded: researchers documented a negative trend in bears’ selection of whitebark pine habitats over a multi-year study period. In years when whitebark pine cone production was poor, bears shifted their peak use of those habitats later in the season by five to eight days, shortening the overall period of use.14PubMed Central. Influence of whitebark pine decline on fall habitat use and movements of grizzly bears in the Greater Yellowstone Ecosystem
This kind of dietary flexibility is characteristic of grizzly bears and helps explain why they can occupy such a wide range of habitats. Bears that lose one food source can pivot to others: elk carcasses, army cutworm moths at high altitude, cutthroat trout, and various berries. But each substitution comes with tradeoffs. Some alternative foods are less calorically dense, require more movement to find, or bring bears into closer contact with people. When bears range further from backcountry habitats to find food, they encounter roads, livestock, and developed land, raising the risk of conflict and mortality.
In the Cabinet-Yaak and Selkirk populations, the food story centers on huckleberries rather than whitebark pine. High-quality huckleberry habitat during prime fruiting months is a major driver of where female grizzlies spend their time, and researchers have developed models to identify the most important huckleberry patches and predict how much energy bears can extract from them.4PubMed Central. Huckleberry Habitat and Its Influence on Two Small Populations of Grizzly Bears (Ursus arctos) Protecting those patches is a tangible conservation action that directly supports the viability of these small populations.
How European Brown Bears Compare
Grizzly bears are a North American subspecies of the brown bear, and their relatives still live across portions of Europe and Asia. European brown bear populations present an interesting counterpoint to the North American situation. Bears in Scandinavia, the Carpathian Mountains, the Dinaric Alps, and scattered populations in Spain, Italy, and Greece share the same species but face a very different landscape: denser human settlement, smaller habitat patches, and centuries more coexistence with agricultural societies.
One review comparing how brown bears respond to human infrastructure across continents found that European bears show stronger avoidance of urban areas than North American grizzlies, while no obvious differences were observed for other types of development like roads or industrial sites.15Acta Silvae et Ligni. Pregled prilagajanja rabe prostora rjavega medveda (Ursus arctos) na antropogene motnje In other words, European bears seem to give towns and cities a wider berth, possibly because centuries of persecution in settled areas have selected for more human-averse individuals or because European settlements are configured differently. This distinction matters for anyone looking at the North American map and wondering whether bears and people can coexist in closer proximity: the European experience suggests that bears can persist in heavily human-modified landscapes, but they adjust their behavior significantly to do it.
Russia holds by far the largest brown bear population in the world, with bears occupying territory from the western border through Siberia to Kamchatka. Japan’s Hokkaido island maintains a small population, and bears also persist in parts of Central Asia. The global brown bear map, taken as a whole, has contracted enormously from historical times but still encompasses a striking range of environments, from Mediterranean scrubland to Arctic tundra.
What Mapping Methods Actually Show
When you see a map of grizzly bear range, it is worth asking how that map was made. The colored areas on most published range maps represent estimated occupied habitat, not a census of exactly where every bear is. In practice, mapping modern grizzly bear populations relies heavily on DNA-based mark-recapture methods. Researchers set up hair snag stations across large areas, collect samples, and use genetic identification to figure out how many unique individuals are present and how they are distributed. In Alberta, this approach covered nearly 50,000 square kilometers across multiple bear management areas and revealed that bear density varied dramatically depending on habitat quality and human-caused mortality risk.6PubMed Central. Using spatial mark-recapture for conservation monitoring of grizzly bear populations in Alberta
These methods mean that a grizzly bear range map is really a probability surface. Bears are most likely to be found in the core of each colored polygon and least likely at the edges, but individuals regularly show up outside mapped boundaries. Dispersing males in particular can travel extraordinary distances, turning up in areas where no resident population exists. A single bear spotted in a new location does not mean the range has expanded; a breeding female with cubs in that location might. Reading a range map with this in mind helps avoid both false alarm and false comfort: the absence of color on the map does not mean bears are never there, and the presence of color does not guarantee a healthy population.
Seed Dispersal and Ecosystem Engineering
Grizzly bears do not just respond to the landscape they live in. They reshape it. In coastal Alaska, brown bears function as major seed dispersers for berry-producing plants. Because the bears eat large quantities of fruit and travel widely, they move seeds across distances and into habitats that smaller animals cannot reach.7The Canadian Field-Naturalist. Seed Dispersal by Brown Bears, Ursus arctos, in Southeastern Alaska Bears that fish for salmon also carry marine-derived nutrients deep into forests when they drag carcasses away from streams. These nutrients fertilize the soil and are taken up by trees and understory plants, creating a measurable difference in vegetation growth near salmon streams compared to otherwise similar sites without bears.
This ecological role is part of why the grizzly bear map matters beyond the bears themselves. Where grizzlies disappear, the cascading effects ripple through plant communities, scavenger populations, and nutrient cycles. Where they return or expand, those effects gradually resume. The argument for maintaining and reconnecting grizzly populations is not purely about saving an iconic species; it is about restoring an ecological process that has been disrupted across much of western North America for over a century.