Grizzly Bear (Ursus arctos)
By: Ranger 1
Photo Credit: Ryan Brooks
The grizzly bear, a subspecies of the brown bear (Ursus arctos), is one of the most powerful terrestrial carnivores in North America. Adult males typically weigh between 135 and 545 kilograms, while females range from 80 to 250 kilograms. The largest subspecies, the Kodiak bear, may exceed 780 kilograms and is found on the Kodiak Archipelago of souther Alaska.
Grizzly bears are most readily identified by their prominent should hump, large head with a dished or concave facial profile, and long, robust claws adapted for digging rather than climbing. Coat coloration varies widely by region, ranging from blonde to dark brown or nearly black. The characteristic “grizzled” appearance is created by silver tipped guard hairs, particularly visible along the shoulders and back.
Grizzly bears occupy one of the largest ranges of any terrestrial mammal, historically extending across North America, Europe, Asia, and North Africa. Today, the are most commonly found in Alaska, Canada, and parts of northern Eurasia. Their adaptability allows them to inhabit a wide range of environments, including coastal ecosystems, boreal forests, alpine meadows above treelike, tundra, and semi-arid landscapes.
Primarily omnivorous, grizzly bears feed on berries, roots & tubers, grasses & sedges, insects, and salmon, while also scavenging carrion and opportunistically preying on large ungulates such as moose, caribou, elk, big horn sheep mountain goat, bison and deer.Activity levels and movement patterns vary seasonally, with bears concentrating around high value food sources such as salmon streams during spawning periods. Home ranges are extensive, often spanning hundreds to thousands of square kilometres, particularly for adult males.
Grizzly bears are generally solitary, though they may congregate where food resources are abundant. They are not territorial in the strict sense, but dominance interactions, especially between males are common.
Mating occurs between May and July. Following delayed implantation, cubs are born during winter hibernation between January and March. Females may loos up to 40% of their body weigh during gestation and nursing. Cubs remain with their mother for several years, learning essential survival behaviours before dispersing.
The accompanying photographs document bear observed in its natural habitat, providing visual confirmation of morphological traits and environmental context consistent with the species; ecological role.
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