USFWS
Alaska Maritime National Wildlife Refuge
Alaska Region   

Wildlife

Mammals

Most of the world’s population of endangered Steller sea lions breed on the refuge. Steve Ebbert, USFWS. Click to Enlarge

One of the special values of the Alaska Maritime Refuge is the concentrations of marine mammals that find sanctuary here to breed and raise their young.

MARINE MAMMALS

    The northern fur seal, endangered Steller sea lion, and harbor seals breed on the beaches and offshore rocky islets. Walrus come ashore to rest on refuge lands in the Bering and Chukchi seas. Sea otters use the nearshore waters around islands in the Aleutian Chain, Southeast Alaska, and off the Alaska Peninsula.

    Winter Visitors

    Polar bears, year-round residents on St. Matthew Island until the end of the 1800s (learn more), sometimes travel on the winter pack ice to refuge lands in the Chukchi or northern Bering Sea.

    Refuge Vital to Survival

    The refuge is key to the life cycles and survival of many of these marine mammals, some of them threatened or endangered.

LAND MAMMALS

On the mainland areas of the refuge, the native mammals are similar to those of nearby areas. On islands, however, native land mammals are either absent or sometimes unique because they have been isolated in their development since the Ice Age.

    None Unless Strong Swimmers

    No native land mammals inhabit most of the Aleutian Islands. Some islands close to the mainland along the Alaska Peninsula and in Southeast Alaska can be reached occasionally by strong swimmers such as bears and river otters.

    Some Unique

    Several remote islands of the Bering Sea are a special case – once joined to the mainland during the Ice age when sea levels were lower. Small mammals were left isolated on three of these island when the sea rose, and now each has a unique species: St. Matthew - St. Matthew Island vole; Unalaska - Unalaska collared lemming; and St. Paul - Pribilof shrew.

    Introduced Harm

    Many islands have land mammals not native there. They were introduced accidentally or intentionally by humans – often devastating the native wildlife and plant life of their new homes. Learn more about the alien/introduced mammals and what the refuge has been doing to restore the natural biodiversity.

Learn more

Native Mammals - Distribution (pdf)

Marine Mammals of the Aleutian Islands (list includes abundance notes)

Sea Otter

FACT SHEET (life history)

Population Fall, Rise, and Fall
More information

Steller Sea Lion

Life History

Northern Fur Seal

Life History

Harbor Seal

Life History

Polar Bear

Life History

Walrus

Life History

Whales

Beluga
Blue
Bowhead
Gray
Humpback
Orca

Last updated:September 8, 2008