|
General
Information
Antarctic
seals are truly fascinating marine animals and a signature
species of the Southern Ocean. They can be found throughout
the Antarctic region, with some species living farther
south than any other mammal. The Antarctic supports a
much larger seal population than does the Arctic, in part
because of the highly productive feeding areas that exist.
Another reason is the lack of native predators such as
polar bears, which also helps explain why seals in Antarctica
show little fear of people. Of the six types of seals
which are found south of the Antarctic Convergence, four
of them are considered true Antarctic species: the Weddell,
the Ross, the
Crabeater
and the Leopard.
Both the Southern Elephant
Seal and the Fur Seal do occasionally
venture onto the continent, but prefer the more northerly
islands of the warmer subantarctic seas.
Seals
were the first Antarctic species to be commercially harvested.
In fact, it was the search for new populations of seals
that led to much of the early exploration of Antarctica
and the Southern Ocean. During the 19th and 20th centuries,
several species of seals were heavily exploited for their
skins or fur and for oil. Whole populations were decimated
as early as the 1820's and some, including the Antarctic
Fur Seal, were driven to the brink of extinction. Today,
seals in the Antarctic are protected by the Convention
for the Conservation of Antarctic Seals, which nonetheless
allows for a small quota of specific species to be taken
for science.
Though
most of their time is spent in the water, all Antarctic
seals, unlike whales,
must return to land to breed. Breeding sites are found
primarily on fast shelf ice and pack ice surrounding the
Antarctic continent or on coastal shores of the more northerly
islands. Breeding behaviors vary greatly among seal species.
Ross, Weddell, and Leopard seals breed alone. Other species,
such as the Antarctic Fur seal and the Southern Elephant
seal prefer larger groups where dominant bulls aggressively
defend 'harems' of females, with territorial disputes
a common occurrence during breeding season.
All
seals feed at sea using sonar (echolocation) and the enhanced
sight of their large eyes. Diets vary but generally consist
of krill (a key species in the Antarctic ecosystem), fish
, and squid.
There
are two main types of seals: the 'eared' seals (Otariidae)
and the 'true' seals (Phocidae), which have no protruding
ear. Only the Antarctic Fur Seal belongs to the Otariidae,
or eared order. The 'eared' seals have hairless hind flippers
that can be brought under their bodies making them very
agile both on land and at sea. 'True' seals have furred
hind flippers that they use to swim, but on land they
are dragged behind the body in awkward 'snakelike' undulations.
Back
to MainWildlife Page
|