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GREY WHALE |
In spite of their huge sizes, their
swimming is gracefully and they perform beautiful haunting songs. Their bodies
encrusted with barnacles and they have their moustaches inside their mouth.
They eat on the smallest creature there is and grow into an unbelievable size.
Baleen whales are in the same family
of cetaceans as their cousins the toothed whales but they are part of the
sub-order Mysticeti. They have no teeth but flexible baleen plates hanging from
the edge of the upper jaw. These baleen plates are like whale-bones. They are
like a massive sieve straining the seawater. To keep their body temperature
they have up to 50cm thick layer of insulating blubber.
The baleen whale consists of a family
of 10 and then again sub-divides it into three groups. The grey whale, the
rorquals whale and the right whale.
The grey whales have the biggest
migration of any mammals. It is up to 20,400km in an annual trip from their
Arctic feeding ground in the summer to the breeding ground in the winter and
then back again. The breeding grounds are the lagoons of Baja California and
the South Korean coast.
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BALEEN |
The grey whale is about 12m long and
has shorter, thicker jaws. It has a comb of yellowish baleen. Its skin is grey
but with the heavily encrustation of barnacles and whale lies it looks more
white. It has a knobbly ridge near its tail end but no dorsal fin.
During the summer, the baleen whale
feeds on huge amount of invertebrates which live on the floor of the
Arctic waters. The grey whale turns on its side, swimming forward, ploughing
the seabed for food. It scoops up its prey with the mud and gravel. When it
comes to the surface it strains its muddy mouthful and eats the crustaceans,
worms and mollusc. On the surface it is the fish and crustaceans.
In November the grey whales swim
south from the arctic. This is their mating season. Sometimes several whales
are rolling together. When a male and female mates, it had been seen, that a
third whale supports them from underneath.
When they arrive, their females have
been pregnant for 13 months. They give birth to an almost 5m long calf. It
would not be possible in the cold Arctic water because the calf has not a
thick blubber. In the warm lagoons the calf grows quickly suckling the
mother's milk. During this time the mother lives off her blubber.
The rorquals - blue whales, fin
whales, sei whales, bryde's whales, humpback and minke whales - have a very
large head. It measures up to a quarter of their body. Underneath, from their
chin to their belly there throat grooves. These expand to a huge bulge when the
whale is feeding. When they are not feeding the rorquals are streamlined and
can swim faster than any other whale.
When they feed, they open their
mouth, take in huge amount of water and with their tongue manoeuvre the food to
the back of their mouth and swallow it. A large blue takes-in
food 70-80 times a day and has about 800 to a 1000kg of krill.
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BALEEN HUMPBACK WHALE |
The humpback whales have a technique
to spiral upward and realize a huge amount of bubbles. That makes the fish to
group together and the whales just swallow them up. Their food supply changes
with the seasons which are krill, copepods which is small
crustaceans, capelin, herring, cod, sardines and mackerel.
Only the Bryde's whale lives near the
shore and in warm water all year round but the other whales migrate. The Minke
whales and blue whales swim right to the edge of the polar ice. The fin whale
does not travel as far as into the polar waters. Neither does the sei
whales which even swim that far.
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BLUE WHALE |
The huge blue whale is the biggest
animal that has ever lived. It can grow up to 30m length and weigh up to 150
tonnes. Its speciality is krill and crustaceans which it traps with its
bristles. The sei whale has finer bristles and its diet is
copepods. The humpback whale is the finest singer of them
all. It is said that it has been known it spooks submarines.
The very long flippers have white edgings which creates eeriness. Only the male
sing and mostly during the breeding season. It can be heard 3km
away. Low frequency songs can be detected over 185km away.
The right whale and the Greenland
right whale, called bowhead, have specially big heads. They are a third
of their body-length. In their deeply arched jaws they have long,
narrow baleen plates. They have no dorsal fin or throat grooves.
The pygmy right whale has a lower jaw and less arched. It also has a
dorsal fin.
The right whale has masses of
barnacles, parasite worms, and whale lice. The whale cleans any seaweed
and other things with his tongue from it baleen and rolls into a ball and spits
it out.
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BALEEN RIGHT WHALE WITH CALF |
Right whale lives in a family of two
to nine whales. They are often seen to leap clear of the water or slapping
it with its tail. It is assumed that it is either of a courtship ritual
or stating the whale position in the group. When the female is receptive
there could as many as half a dozen of male swimming around her. The
female can swim on its back to reject the male's approach but the male
tries to roll her over by head-butting.
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BALEEN WHALE BLOWS V-SHAPED |
The toothed whale has only one
blowhole but the baleen whale has twin blowholes. It is a crescent-shaped
slit and protected by a fatty, fibrous pad. It opens by the muscles and
closes by water pressure. Each whale distinguishable blows. The
grey whale has a short, puffy, vertical spout. The blue whale has a spout
of 6-10m high. The right whale has a double spout of 4-5m high.
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