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.
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
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
refuge is key to the life cycles and survival of many of these marine mammals,
some of them threatened or endangered.
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.
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.
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.
Mammals - Distribution (pdf)
Mammals of the Aleutian Islands (list includes abundance notes)
SHEET (life history)
Fall, Rise, and Fall
Steller Sea Lion
Northern Fur Seal
Last updated:September 8, 2008