General
Information
Whales
are considered by many to be the most magnificent and intelligent
of the Antarctic marine mammals. Members of the order Cetacea
which includes dolphins and porpoises, whales are divided
into two groups: toothed (Odontoceti) and baleen (Mysticeti).
Toothed whales have narrow jaws lined with peg-like teeth
which they use to catch fish, squid, and other marine mammals,
swallowing them whole. They are smaller than baleen whales
and only have one blowhole. The Killer
(Orca) whale and the Sperm whale
are the only toothed whales found in the Antarctic region.
Baleen whales have comblike structures instead of teeth that
are used to filter krill and fish from the water. They are
larger than toothed whales and have two blowholes. The Blue,
Fin, Humpback,
Minke, Sei,
and Southern Right Whales are
the baleen whales found in the Antarctic.
In the early and mid-1900's, several species of whales in
the Southern Ocean were hunted to the edge of extinction,
but they are now gradually recovering thanks to international
regulation. However, the great abundance of whales in the
Antarctic region remains a thing of the past. Today the entire
area around the continent of Antarctica has been declared
an international whale sanctuary with whaling activities closely
monitored by the International Whaling Commission (IWC).
Whales
have sleek, streamlined bodies that move easily through the
water. They are the only mammals, other than manatees, that
live their entire lives in the water, and the only mammals
that have adapted to life in the open oceans. Like all mammals,
whales have lungs and they breathe air. They are warm-blooded,
have a four-chambered heart, and nurse their young with milk
from the mother. Unlike fish which swim by moving their tail
left and right, whales swim by moving their flukes or tail
flippers up and down.
All
Antarctic whale species migrate long distances, feeding in
the cold, nutrient-rich Southern Oceans during the austral
summer then heading to warmer northern waters to breed and
give birth to their young during the winter months. Some whale
species travel alone or in pairs while others travel in large
social groups called pods.
Female
whales reach sexual maturity between 6 and 11 years old. Pregnancies
usually last about a year and rarely is more than one calf
born in a season. Though whale calves can swim at or soon
after birth, mother whales protect and feed them for up to
12 months. At birth, the young calves are frequently mottled
in color and have a sparse covering of hair which they lose
as adults. A typical whale's lifespan is between 20 and 40
years though some may live to be 80.
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