musculus [bah lE nop' teh ruh muhs ku'
luhs]; the largest animal to have ever lived
Dwarfing even the largest
dinosaurs, adult blue whales average 80 to 105
feet in length and weigh up to 200 tons. The
tongue is as heavy as an elephant, and the heart
the size of an automobile. Females are larger
than males in both length and weight.
The blue whale's head is broad,
flat, and almost U-shaped, with a single ridge
that extends from just forward of the blowholes
to the tip of the snout. The body is long and
tapered, and ends in wide, broad, triangular
flukes. The dorsal fin, which is located about
three-fourths of the way back on the body, is
small and either triangular or curved in shape.
Although it looks truly blue
underwater, the blue whale is actually more of a
mottled blue-gray in color. Its underbelly often
takes on a yellowish hue due to the presence of
microorganisms in its skin.
Distribution and Habitat
Blue whales can be found in all the oceans,
except for the extreme polar regions. It is
common for them to summer in sub-arctic and
arctic waters and migrate towards equatorial
waters as their food supply moves.
Blue whales feed almost exclusively on krill,
a variety of shrimp that is only about an inch or
two long, but can eat 4 to 8 tons of it per day.
Lacking teeth, they feed by taking in enormous
mouthfuls of water then forcing the water out
through baleen plates that line the inside the
mouth; they then use their enormous tongues to
sweep the krill off the plates and down into the
Mating usually occurs while the blue whales
are in warmer waters, and a single calf is born
about one year later, when the mother is again in
warmer water. The calf is about 25 feet long at
birth and can weigh as much as three tons. It
also grows rapidly, gaining about 200 pounds a
day in its first year, and is weaned at about
eight months (or when it is about 52 feet long).
The mother will not breed again until her calf is
It takes six to ten years for a blue whale to
reach sexual maturity, and it is not uncommon for
a blue whale to live 80 to 90 years (or more) in
Other Habits and Behaviors
A blue whale's spray (when it exhales) is tall
and straight, and can reach almost 30 feet into
Blue whales are typically seen either alone or
in pairs, but will on occasion come together in
small groups (pods). When food is plentiful there
may be as many as 50 or 60 blue whales in one
group, although such groups are temporary and
there is generally no relationship between most
individual pod members.
Blue whales produce a variety of sounds,
including pulses, groans and moans. Scientific
investigation has shown that blue whales may be
capable of hearing each other up to 1,000 miles
away. Whether the whales are actively
communicating with each other is not known,
A blue whale can swim at more than five miles
per hour, and accelerate to more than 20 miles
per hour when agitated.
The blue whale is an endangered species, with
only about 25,000 remaining in the wild. It is
protected by treaties signed at the 1966
International Whaling Commission.
genus & species Balaenoptera musculus
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