Alaska is a vast and ecologically diverse region, providing habitat for three distinct species of bears: the brown bear, the American black bear, and the polar bear. This unique environment allows these large mammals to thrive, ranging from dense coastal forests to the treeless Arctic tundra. Seeing these animals in their natural settings has made Alaska a premier location for wildlife viewing. Though they share the same taxonomic family, they have evolved specific physical characteristics and dietary needs that suit their particular Alaskan landscapes.
The Majestic Brown Bear
All brown bears in Alaska belong to the species Ursus arctos, but they are distinguished by location and diet, which influences their size. The name “brown bear” is used for larger coastal populations that benefit from rich, seasonal salmon runs. These coastal bears can reach immense sizes, sometimes exceeding 1,500 pounds and standing up to nine feet tall on their hind legs. Smaller interior bears, often called “grizzlies,” inhabit areas like Denali National Park. Grizzlies have a more varied diet of roots, berries, vegetation, and small mammals, resulting in smaller sizes, typically weighing between 200 and 700 pounds. Brown bears are identifiable by their prominent shoulder hump, composed of strong muscle used for digging, and their long, straight claws, measuring two to four inches. They also possess a broad, concave or “dished” facial profile, distinguishing them from other species.
The Widespread American Black Bear
The American black bear, Ursus americanus, is the most abundant and widely distributed bear species, inhabiting most of Alaska’s forested areas. They are absent from the extreme northern regions beyond the treeline, the Yukon-Kuskokwim Delta, and certain islands. Despite the name, their fur can range in color from jet black to brown, cinnamon, blonde, or even a bluish-gray known as the Glacier Bear. Identification should focus on physical features that contrast with the brown bear. Black bears lack the prominent shoulder hump and have a straight facial profile. Their claws are shorter and more curved, typically less than 1.5 inches long, which makes them excellent tree climbers. Adults are significantly smaller than brown bears, typically weighing between 200 and 500 pounds.
The Arctic Specialist Polar Bear
The polar bear, Ursus maritimus, is a marine mammal uniquely adapted to the harsh environment of the Arctic. Its presence in Alaska is geographically restricted to the northern and western coasts, following the seasonal movements of the Arctic sea ice. The sea ice serves as their primary platform for hunting ringed and bearded seals, which constitute the majority of their blubber-rich diet. Their specialized characteristics include a dense coat of fur and a thick layer of blubber to withstand temperatures that can drop to -50° Fahrenheit. Polar bears have a long neck, a narrow head, and small, fur-covered ears to minimize heat loss. Their enormous paws, which are nearly covered in fur on the bottom, act as snowshoes and powerful paddles for swimming long distances.