Grizzly bears occupy an extraordinarily diverse range of habitats, from the temperate rainforests of the BC coast to the open tundra above treeline in Alaska and the boreal foothills of northern Alberta. This breadth of habitat tolerance reflects the species’ fundamental ecological flexibility — grizzlies are generalist omnivores capable of exploiting almost any high-calorie food source that becomes available.
Habitat Types
Temperate rainforest (coastal BC and southeast Alaska): Coastal grizzly populations exploit the rich salmon runs of river systems that drain directly into Pacific fjords. These bears have access to the highest-calorie food sources of any grizzly population and grow correspondingly larger. Knight Inlet, the Khutzeymateen Sanctuary, and the river systems of the Great Bear Rainforest represent the productive core of coastal grizzly habitat.
Mountain foothills and subalpine (Alberta, BC Rockies, Montana): Interior grizzlies in the Rocky Mountain system occupy a gradient from valley-bottom riparian corridors to alpine meadows above treeline. Spring foraging typically begins in valley bottoms as vegetation emerges from snowmelt; summer shifts to alpine zones where ground squirrels, glacier lilies, and high-elevation berry fields concentrate bears.
Boreal forest (BC interior, Yukon, NWT): Large areas of northern Canada support grizzly populations in boreal forest habitats less studied than coastal or mountain populations. These bears rely more heavily on ungulates, particularly moose and caribou, and on root and tuber digging in bogs and wetlands.
Arctic tundra (Alaska, northern Yukon): Tundra grizzlies range widely across open terrain, exploiting ground squirrel concentrations, berries, and seasonal fish runs. These populations are among the most visible, as the open topography permits long-distance observation unavailable in forested systems.
Elevation Use
Grizzly bears in mountain systems demonstrate seasonal vertical migration. Denning sites are typically on steep north-facing slopes at elevation, protected by deep snowpack. Spring ranges centre on south-facing valley slopes where snow melts earliest. Summer sees bears moving to high-elevation meadows as lower vegetation matures. Autumn brings bears back to lower elevations where berry crops ripen.
This vertical migration pattern exposes bears to roads and human infrastructure at multiple elevation bands, creating the intersection points where conflict and mortality risk are highest.
Ecosystem Role
The grizzly bear’s role as a keystone species extends well beyond its position at the apex of the food chain. Studies in Alaska and BC have documented how salmon-fishing grizzlies transport marine nutrients deep into forest interiors — the nitrogen from salmon carcasses dragged into the woods fertilizes vegetation visible decades later in forest plots. A single bear may carry several hundred salmon carcasses into the forest in a single autumn.
Berry consumption and seed dispersal in grizzly scat represents another ecological function: bears move large quantities of berry seeds across their home ranges, contributing to the regeneration of fruiting shrubs in disturbed and recovering areas.
Digging activity — in pursuit of ground squirrels, roots, and overwintering insects — turns over significant volumes of soil, aerating compacted soils and creating microhabitats for invertebrates and plant colonization.
Habitat Requirements and Connectivity
Grizzly bear population viability depends on habitat that meets three core requirements: sufficient food resources to support hyperphagia, safe denning terrain, and connectivity to adjacent populations.
The third requirement — connectivity — is the most difficult to maintain in a fragmented landscape. Bears that cannot move between population centres cannot maintain the genetic exchange that prevents inbreeding depression. Road networks, even low-volume secondary roads, dramatically increase mortality risk for bears attempting to cross.
The Rocky Mountain wildlife corridors that connect the national parks of Alberta and BC are the critical infrastructure maintaining population viability for interior grizzlies in Canada. The national parks themselves represent the protected core of this system, but the corridors between them are equally essential.
For guidance on viewing grizzlies in their natural habitat, see the full Grizzly Bears species guide. Travellers entering bear country should review the bear safety guide before departure.