Alaska covers a vast expanse of diverse landscapes, from arctic tundra to boreal forests and rugged coastlines. This geographical variety creates a mosaic of habitats for a wide array of native species. The wildlife here has developed specific adaptations to survive the seasonal extremes and challenging conditions of these northern biomes. This environment supports a distinct population of animals recognized for their size and resilience.
Iconic Land Mammals of the Interior
The interior of Alaska is home to some of North America’s most recognizable land mammals. The Alaska-Yukon moose, the largest subspecies of the deer family, can stand over six feet tall at the shoulder, with large bulls weighing up to 1,600 pounds. These massive herbivores browse heavily on willows, birch, and aquatic vegetation, often consuming up to 50 pounds of forage daily.
Caribou are known for their impressive annual migrations, traveling hundreds of miles between their wintering grounds in the boreal forest and their spring calving grounds on the open tundra. Alaska hosts numerous distinct herds, including the large Western Arctic Herd. These movements are essential for finding adequate food, primarily lichens in winter and flowering plants during the brief summer season.
The state is also inhabited by two bear species: the Grizzly (or Brown) bear and the American Black bear. Grizzly bears are generally larger with a distinct shoulder hump and long, straight claws suited for digging, preferring open environments like alpine meadows and tundra. Black bears are typically smaller, possessing shorter, curved claws that enable them to climb trees, and are more commonly found in forested areas.
Gray wolves roam nearly all of Alaska’s territory and function as apex predators, maintaining a complex social structure within their packs. These highly social canids maintain large territories, sometimes spanning over 600 square miles, and primarily prey on the abundant moose and caribou populations.
Unique Marine Life of Alaskan Waters
Alaska’s coastlines, bordering the nutrient-rich waters of the Gulf of Alaska and the Bering Sea, support an immense diversity of marine life. Humpback whales migrate thousands of miles to feed in these cold waters on krill and small schooling fish. They often use a cooperative hunting method called bubble-net feeding, where a group of whales releases a ring of bubbles to corral their prey.
Orcas, or killer whales, are apex predators in these waters, divided into distinct populations with specialized diets. Resident orcas primarily consume fish, particularly Chinook salmon, while transient orcas hunt marine mammals like seals and porpoises. They utilize complex, highly organized social groups and hunting strategies.
The Pacific walrus, the largest pinniped species, is adapted to the icy conditions of the Bering and Chukchi seas. They use their long tusks to pull themselves onto ice floes and to break breathing holes in the sea ice. Most large marine mammals, including various seal species like the bearded and harbor seals, rely on a thick layer of blubber for insulation against the frigid ocean temperatures.
Sea otters, a keystone species, maintain warmth not through blubber, but with the densest fur of any mammal, which traps a layer of insulating air. They consume significant amounts of shellfish, including sea urchins, and their presence helps maintain the health of kelp forests.
The cold marine environment also sustains five species of Pacific salmon, which are born in freshwater, mature in the ocean, and return to their natal streams to spawn:
- Chinook
- Sockeye
- Coho
- Pink
- Chum
Pacific halibut, the largest flatfish, are bottom-dwellers that can reach over eight feet in length, with both eyes migrating to one side of the head as they mature.
Avian Species and Smaller Terrestrial Fauna
Alaska’s skies and underbrush are populated by numerous native bird species and smaller mammals that exhibit adaptations to the northern environment. The Bald Eagle has a wingspan that can reach seven and a half feet, and the highest nesting densities in the United States occur along the state’s southeastern coast. These raptors primarily feed on fish, congregating in large numbers along rivers during the salmon runs.
Coastal waters and cliffs are home to seabirds, including the Tufted and Horned Puffins, which use their colorful bills to carry small fish back to their nests. Many species of waterfowl, such as geese and ducks, migrate through or nest in Alaska’s extensive wetland areas, taking advantage of the summer’s long daylight hours.
The Arctic Fox exhibits a seasonal adaptation, changing its coat from dark brown or gray in summer to a dense, insulating white in winter for camouflage. Snowshoe hares also change color seasonally, using their enlarged hind feet to traverse deep snow. The wolverine, a solitary and powerful member of the weasel family, travels long distances, primarily inhabiting the tundra and boreal forests. The elusive lynx, characterized by its tufted ears and large paws, is a specialized predator whose population cycles closely follow the abundance of its primary prey, the snowshoe hare.