Biggest
Mammal ....
BLUE WHALE
Balaenoptera
musculus
Blue
Whales are True Giants
Imagine if you were sailing the ocean for the
first time, venturing into a place you'd never seen before, and you
look over the side of your boat into the water and see the creature
in the photo at left. Imagine that you know almost nothing about what
lives in the sea, or what to expect from any creatures you might see.
This strange creature swimming near the surface is longer than the ship
you are sailing on. You might be a little scared, especially having
never seen it before and not knowing what it is capable of. You might
even be worrying about whether this creature eats humans. The
sheer size of it makes you wonder if it can capsize your ship in pursuit
of a meal. But you have nothing to fear for this enormous animal is
merely a whale.
For many, many years ancient
sailors had rare encounters with these gigantic ocean mammals and were
terrified by their overwhelming size and powerful tails. You can understand
a little of the fear and trepidation they might have felt upon seeing
these huge, mysterious creatures for the first time. Today we know them
to be virtually harmless to humans and that they have quite a bit in
common with us – they, too are warm-blooded mammals that must
breathe air. They are highly social animals with complex languages and
intelligence. Most importantly, they are not monsters at all, but gentle
giants we’ve come to respect, admire and protect.
Gentle Giants
In scary
movies the gigantic creature that swims in the ocean, or the huge beast
that roams the streets, are evil monsters bent on harm and destruction.
But in nature (in real life), the very largest of the large creatures
have been virtually harmless to humans. In fact, magnificent creatures
such as the great blue whale have suffered most at the hands of humans
bent on destruction. Blue whales, as well as many other whale species,
have been hunted to the brink of extinction by people from all over
the world for centuries. It's only recently, in this century, that we
as a species have begun to appreciate the value of all living creatures.
We have come to feel that wiping any species of animal off the face
of the earth forever is an evil thing for humans to do. Blue whales
have been put on the United States' endangered species list. Whalers
in the 19th and 20th centuries hunted this giant nearly to extinction,
killing as many
as 29,000
in 1931, probably the peak year.
Big
in Every Way
Blue
whales diet consists mainly of krill, a tiny shrimp that lives in tremendously
large schools in almost every ocean of the world. Krill is probably
one of the most plentiful food species (outside of insects) anywhere
on earth. It's gotta be to keep up with the blue whales' big appetite.
A big blue can eat over a thousand krill at one time swallowing them
with a tongue that weighs as much as an elephant! Blue whales eat the
krill using a special type of filter on their mouths called a baleen.
By gulping enormous amounts of sea water containing the live krill the
blue whale closes its mouth and flushes the sea water back out through
the filter leaving the krill behind for it to swallow. Small fish and
plankton are also favorite food items of the whale. It takes about 8,000
lbs/3600kg of fresh seafood a day to keep the blue whale well fed.
Probably
the most spectacular thing about blue whales that's bigger than big
is the sounds they make. If you have speakers on your computer you
should hear a recording of "blue whale speech" playing in
the background. Scientists have measured the low-frequency (deep rumbling)
sounds they make when they communicate with each other by using a
decibel meter.
Some of their vocalizations have been recorded as loud as 188 decibels
and can be heard as far as 530 mi/848km away. To give you an idea
of just how loud 188 decibels is a commercial jet taking off makes
a sound of 120 decibels. That makes whales, by far, the loudest living
thing anywhere on earth!
Why is the Blue
Whale So Big?
Scientist don't really
know for sure, but they are sure of one thing - as big as the ancient
dinosaurs were they were NEVER as big as the blue whale is. The
blue whale is the largest creature to have ever lived on earth!
One of the most important reasons that whales have become so large
is they have more SPACE - more room to roam. Remember: over 70%
of the earth is covered in ocean water.
Another nice thing
about living in the oceans, besides all the real estate, is the
weightlessness effect of water. If you like to swim or SCUBA dive
you know how it feels to be in the water - almost like floating
in
space. (In fact,
NASA sometimes trains their astronauts inside huge tanks of water
to get familiar with working in a zero-gravity environment.) It's
the weightlessness of the ocean environment that allows a whale
to maintain such huge proportions. Instead of relying on a skeleton
to support the weight of its massive bulk the buoyancy of the surrounding
ocean water supports the weight of the whale's body tissues. If
a blue whale were to be removed from the ocean it would smother
under its own weight - a result of the effects of gravity.
