Essay/Term paper: Blue whales

Essay, term paper, research paper:  College Papers

The Blue whale is the largest creature of the sea, in fact, it is the
largest creature known to man. Contrary to what most people think,
even though Blue whales live in the sea, they are mammals. They
breathe air, have their babies born alive and can live anywhere from 30
to 70 years. The Blue whale is a baleen whale, and instead of having
teeth, Blue whales have around 300-400 baleen plates in their mouths.
They fall under the category of the rorquals, which are the largest of
the baleen family. The scientific name of the Blue whale is,
Balsenoptera musculus.

Key Words: Balaenoptera musculus, Suborder Mysticeti, balaenoptera
intermedia, balaenoptera brevicauds, baleen whale, rorqual, calf,
sulfur bottom, Sibbald^s Rorqual, Great Northern Rorqual, gulpers,
blowholes, blubber, oil, keratin, krill, copepods, plankton, orcas,
endangered

Introduction Whales are separated into two groups, the baleen and the
toothed whales. The blue whale is the largest baleen whale and the
largest animal that ever lived on Earth, including the largest
dinosaurs. Baleen are rows of coarse, bristle-like fibers used to
strain plankton from the water. Baleen is made of keratin, the same
material as our fingernails. They live in pods, the have two
blowholes. The blue whale has a 2-14 inch (5-30cm) thick layer of
blubber. Blue whales (Balaenoptera musculus) are baleen whales
(Suborder Mysticeti). They are one of 76 species and are marine
mammals.

Background The Blue whale is called a ^rorqual^, a Norwegian word for
^furrow^ referring to the pleated grooves running from its chin to its
naval. The pleated throat grooves allow the Blue whale^s throat to
expand during the huge intake of water during filter feeding; they can
^hold 1,000 tons or more of food and water when fully expanded^ (Small
1971). Blue whales have 50-70 throat grooves.

Blue whales grow up to about 80 feet (25m) long on average, weighing
about 120 tons. The females are generally larger than the males, this
is the case for all baleen whales. ^The largest specimen found was a
female 94 feet (29m) long weighing more than 174 tons^ (Satchell
1998). The head of the Blue whale forms up to a quarter of the total
body length. Compared with other rorquals, the head is very broad.
The blue whale heart is the size of a small car and can pump almost 10
tons of blood throughout the body. They have a very small, falcate
(sickle-shaped) dorsal fin that is located near the fluke, or tail.
Blue whales have long, thin flippers 8 feet (2.4m) long and flukes that
are 25feet (7.6m) wide.

The blue whale^s skin is usually blue-gray with white-gray spots. The
underbelly has brown, yellow, or gray specks. During the winter, in
cold waters, diatoms stick to the underbelly, giving it a yellow to
silver- to sulfur-colored sheen; giving the blue whale its nick-name of
^sulfur bottoms^. Other names include Sibbald^s Rorqual and Great
Northern Rorqual.

Blue whales (like all baleen whales) are seasonal feeders and
carnivores that filter feed tiny crustaceans (krill, copepods, etc),
plankton, and small fish from the water. Krill, or shrimp-like
euphasiids are no longer than 3 inches. It is amazing that the world^s
largest animals feed on the smallest marine life. Blue whales are
gulpers, filter feeders that alternatively swim then gulp a mouthful of
plankton or fish. ^An average-sized blue whale will eat 2,000-9,000
pounds (900-4100kg) of plankton each day during the summer feeding
season in cold, arctic waters (120 days)^ (Hasley 1984).

The blue whale has twin blowholes with exceptionally large fleshy
splashguards to the front and sides. It has about 320 pairs of black
baleen plates with dark gray bristles in the blue whale^s jaws. These
plates can be 35-39 inches (90cm-1m) long, 21 inches (53cm) wide, and
weigh 200 pounds (90kg). This is the largest of all the rorquals, but
not the largest of all the whales. The tongue weighs 4 tons.

Blue whales live individually or in very small pods (groups). They
frequently swim in pairs.

When the whale comes to the surface of the water, he takes a large
breath of air. Then he dives back into the water, going to a depth of
350 feet (105m). Diving is also the way in which whales catch most of
their food. Whales can stay under water for up to two hours without
coming to the surface for more air. Blue whales breath air at the
surface of the water through 2 blowholes located near the top of the
head. ^ They breathe about 1-4 times per minute at rest, and 5-12 times
per minute after a deep dive^ (Hasley 1984). Their blow is a single
stream that rises 40-50 feet (12-15m) above the surface of the water.

Blue whales are very fast swimmers; they normally swim 3-20 mph, but
can go up to 24-30mph in bursts when in danger. Feeding speeds are
slower, usually about 1-4mph.

Blue whales emit very loud, highly structured, repetitive low-frequency
sounds that can travel form many miles underwater. They are probably
the loudest animals alive, louder than a jet engine. These songs may
be used for locating large masses of krill (tiny crustaceans taht they
eat) and for communicating with other blue whales.

Blue whales typically are found in the open ocean and live at the
surface. They are found in all the oceans of the world. The majority
of Blue whales live in the Southern Hemisphere. The subspecies found
in the Southern Hemisphere are the balaenoptera musculus. The smaller
populations inhabit the North Atlantic and North Pacific. These
Northern Hemisphere Blue whales are the balaenoptera brevicauda. They
migrate long distances between low latitude winter mating grounds and
high latitude summer feeding grounds. They are often seen in parts of
California, Gulf of California (Sea of Cortez), Gulf of St. Lawrence,
Canada and the northern Indian Ocean. Blue whale breeding occurs
mostly in the winter to early spring while near the surface and in warm
waters. ^The gestation period is about 11-12 months and the calf is
born tail first (this is normal for cetaceans) and near the surface in
warm, shallow waters^ (Hasley 1984). The newborn instinctively swims
to the surface within 10 seconds for its first breath; it is helped by
its mother, using her flippers. Within 30 minutes of its birth the
baby whale can swim. The newborn calf is about 25 feet (7.6m) long and
weighs 6-8 tons. Twins are extremely rare (about 1% of births); there
is almost always one calf. The baby is nurtured with its mother^s
fat-laden milk (it is about 40-50% fat) and is weaned in about 7-8
months. A calf may drink 50 gallons of mother^s milk and gain up to 9
pounds an hour or 200 pounds a day. The mother and calf may stay
together for a year or longer, when the calf is about 45 feet (13m)
long. Blue whales reach maturity at 10-15 years.

Blue whales have a life expectancy of 35-40 years. However, there are
many factors that limit the life span of the Blue whale. Packs of
killer whales (orcas) have been known to attack and kill young blue
whales or calves. Man also hunted blue whales until the International
Whaling Commission declared them to be a protected species in 1966
because of a huge decrease in their population.

The Blue whale was too swift and powerful for the 19th century whalers
to hunt, but with the arrival of harpoon canons, they became a much
sought after species for their large amounts of blubber. They were
also hunted years ago for their baleen, which was used to make brushes
and corsets. But it was their size and high yield of oil that made
them the target of choice for modern commercial whalers. Before mans
intervention there were 228,000 Blue whales swimming the oceans of the
world. ^Between 1904 and 1978, whalers scoured the seas for this huge
cetacean, most were taken in the Southern Hemisphere, many illegally^
(Satchell 1998). As the population figure suggests, it was
relentlessly slaughtered for every reason imaginable, almost to the
point of extinction.

Another reason why Blue whales are almost extinct is pollution. Mosst
of their illnesses are contracted by pollution.

It is estimated that there are about 10,000-14,000 blue whales
world-wide. Blue whales are an endangered species. They have been
protected worldwide by international law, since 1967. The blue whale
was listed as endangered throughout its range on June 2, 1970 under
Section 7 of the Endangered Species Conservation Act of 1969. They are
not to be hunted by anyone for any reason at all. Suggestions are that
some populations may never recover.


Conclusion Although Blue whales are now protected, we still must not
hunt or kill them in their delicate balance of life. Some people
believe that whales and dolphins are animal of mystery and beauty, and
that a dead whale is an omen, good or bad. Most people say that all
humans must protect all whales. We need to save these great water
giants.



Works Cited/Consulted

Berger, C. 1998 Making Sense of the Songs Whales Sing. Natural Wild Life. Volume 36, Number 8.

Hasley, W. 1984. Collier^Òs Encyclopedia. P.F. Coillier, Inc. New York, NY.

Mulvaney, K. 1998. A Canny Way with Whalers. New Scientist. Volume 157, Number 2118.

Satchell, M. 1998. A Whale of a Protest: Animal-Rights Activists Hope to Keep an Indian Tribe from Bringing Home the Blubber. US News and World Review. Volume 125, Number 13.

Small, G. 1971. The Blue Whale. New York Columbia University Press. New York, NY.

Zimmer, C. 1998. The Equation of a Whale. Discover. Volume 19, Number 4.