The Blue whale is the largest creature of the sea; in fact, it’s 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. 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. 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). They average about 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 also large, the size of a small car and can pump almost 10 tons of
blood throughout the body. They also 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). 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, it takes a large breath of
air. Then it 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. They are
also 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. The
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 that 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 sub-species found in the Southern

Hemisphere are the balaenoptera musculus.