Blue Whales Essay

This essay has a total of 1731 words and 12 pages.

Blue Whales



Abstract
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.

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