Blue Whales Essay, Research Paper
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; th
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.
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