Alaska represents one of the largest and most ecologically intact wilderness areas in the world. Its sheer size and latitude create diverse landscapes, ranging from temperate rainforests and sprawling boreal forests to alpine tundra and the Arctic coastal plain. This geographic variety supports a high biological diversity uncommon in other regions of North America. These vast ecosystems provide habitat for numerous large and small animal species adapted to the extreme seasonal changes of the far north.
The Iconic Land Mammals
Alaska is home to the world’s largest subspecies of moose, often sighted in interior forests and along river drainages. These herbivores possess long legs adapted for navigating deep snow and foraging on willow, birch, and aquatic vegetation. Male moose develop antlers annually, which can span up to six feet in width.
The state is defined by its bear populations, including black bears and brown bears. Black bears are found in forested areas, while brown bears (grizzlies in inland areas) are widely distributed. Coastal brown bears grow larger than their inland counterparts due to rich protein sources like salmon during spawning runs. Brown bears have a distinctive muscular hump over their shoulders, which provides the power needed for digging and hunting.
Caribou, recognized as reindeer elsewhere, travel in vast herds across the open tundra and boreal forest. They undertake one of the longest terrestrial migrations, sometimes traveling over 2,000 miles annually between summer calving grounds and winter foraging areas. Unlike other deer species, both male and female caribou grow antlers, though the male’s are larger and more branched.
Dall sheep are another unique Alaskan ungulate, specifically inhabiting the rugged, steep mountainous terrain of the state. Their white coats provide camouflage against the snowy peaks, and they possess specialized hooves that allow them to navigate the precarious cliffs and ridges of their high-altitude environment. Thriving in this isolated habitat protects them from many lowland predators.
Marine and Coastal Wildlife
Alaska’s waters, bordering the Gulf of Alaska, the Bering Sea, and the Arctic Ocean, host immense populations of marine mammals. Humpback whales are common summer visitors to the nutrient-rich Gulf of Alaska, where they use bubble-net feeding, a cooperative strategy, to corral schooling fish. Orcas, or killer whales, are also prevalent, with distinct populations specializing in hunting marine mammals or fish.
The Bering Sea and northern coasts feature ice-associated species that rely on seasonal sea ice for resting, breeding, and foraging. Pacific walruses use ice floes as haul-out sites, diving to feed primarily on clams and other bottom-dwelling invertebrates. Ringed seals, the smallest and most common Arctic seal, use strong claws to maintain breathing holes in the thick winter ice.
Coastal environments are home to the sea otter, often seen floating on its back while eating or resting. These marine mammals lack a blubber layer and rely instead on a dense fur coat and a high metabolism to stay warm in the cold Pacific waters. Harbor seals and Steller sea lions are frequently found near shorelines, resting on rocky outcroppings and beaches.
Avian Residents and Migrants
Alaska is a globally significant destination for birds, hosting over 470 species, with the majority being long-distance migrants. Over 80% of the state’s bird species migrate, connecting Alaska to six continents through their annual journeys. Shorebirds such as the Bar-tailed Godwit perform non-stop flights over the open ocean, migrating thousands of miles from their Arctic breeding grounds.
The state has the highest density of bald eagles in North America, particularly along coastlines where abundant fish stocks provide a reliable food source. These raptors often perch high in trees, scanning the water for prey, and are a common sight in coastal towns. Coastal cliffs and islands are nesting grounds for large colonies of seabirds.
Species like common murres and tufted puffins congregate in these areas to raise their young, with some colonies numbering in the millions of individuals. The vast tundra also supports year-round residents like the Snowy Owl, a hunter whose white plumage provides camouflage while it preys on rodents. Many migratory waterfowl, including various species of ducks and geese, also rely on Alaska’s vast wetlands and estuaries for breeding.
Smaller Terrestrial Predators and Prey
Beyond the large, iconic species, a network of smaller predators and their prey are important to the Alaskan food web. Gray wolves operate as highly efficient pack hunters, preying on the large ungulates like caribou and moose. Their presence helps maintain the health of the herds by often targeting the old, sick, or young animals.
Wolverines, known for their solitary nature and strength, are mid-sized predators that act as important scavengers, often claiming carcasses left by larger animals. They have a reputation for persistence and can cover vast territories in search of food. Arctic foxes are highly adapted to the extreme cold, possessing a thick winter coat and an opportunistic diet.
These foxes rely heavily on small rodents like lemmings and voles, but they will also follow polar bears and wolves to scavenge leftovers from their kills. The snowshoe hare is a primary prey species in the boreal forest, exhibiting a classic predator-prey population cycle with the Canada lynx. Arctic ground squirrels, the largest ground squirrel in North America, are a common food source for many predators, including grizzly bears, which frequently dig up their burrows.