Blue Whales


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
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
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
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
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.


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