The Blue whale is, and always has been, the largest animal ever to exist on earth. This whale can grow to a length of 33m (110ft) and weigh 190 tonnes but on the average it is much smaller. The Blue whale is called a "rorqual" a Norwegian word for "furrow" and refers to the pleated grooves running from its chin to its navel. The throat grooves, in addition to streamlining the shape of the whale, allow the throat area (cavum vent-rale) to expand tremendously during feeding, and can hold 1,000 tons or more of food and water when fully expanded. By taking tonnes of water into its mouth and filtering out the fish or krill with its baleen plates a medium-sized Blue whale can eat over 4 tons of krill a day.
The head of the Blue whale forms up to a quarter of the total body length and compared with other rorquals is very broad. It has twin blowholes with exceptionally large fleshy splashguards to the front and sides. The dorsal fin is small and triangular with a tip which may be rounded or pointed. It is set three-quarters of the way back and can be moderatly falcate. The baleen plates in the mouth of the Blue whale can be 90cm-1m (35-39in) in length the longest of all the rorquals but not the longest of all whales.
The underside of the whale is yellow or mustard-coloured and is not a natural pigmentation but is caused by the presence of algae, called diatoms, which attach themselves to the whale's body. This is most commonly observed in animals living in cold waters near the poles. It has broad flukes with slightly concave or straight trailing edges and a small notch in the middle. The flippers are long and slender and about one seventh of body length.
The blow is spectacular, rising to 9 metres (30ft) high it is a slender, straight column. Breathing sequence usually involves 2-6 minutes at the surface, blowing once every 10-20 seconds, followed by a dive for 5-20 minutes. The fin is visible briefly before the whale arches its back in preparation for the dive. Its tail stock may arch and its flukes may be visible but often they simply sink below the surface.
Blue whales rarely ever breach clear of the water. Juveniles have been observed breaching and landing on their sides or stomaches. Some individuals are easy to approach while others can be difficult. The whale can accelerate to speeds of over 30km/h (19mph) when chased, but usully much slower, and can dive to depths of 150m (490ft) or more.
Subfamily Balaenopterinae.There are 3 different subspecies:
balaenoptera musculus - Northern
Other Names: Sulphur-bottom, Sibbald's Rorqual, Great Northern Rorqual
Most Blue whales live in the Southern Hemisphere while smaller populations inhabit the North Atlantic and North Pacific. They migrate long distances between low latitude winter mating grounds and high latitude summer feeding grounds and are often seen in parts of California, Gulf of California (Sea of Cortez), Gulf of St. Lawrence, Canada and the northern Indian Ocean.
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 against the law. Current figures suggest that a mere 11,700 animals are left. As the population figure suggests, it was ruthlessly and relentlessly slaughtered for every reason imaginable, almost to the point of extinction. Now on the endangered list, the Blue Whale is protected (since 1967) worldwide by international law. It is not to be hunted by anyone for any reason at all. Suggestion are that some populations may never recover.
Lifespan 35-40+ years.
source"Whales in Danger"
Gentle GiantsIn 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. Big Guys in a Big 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 pounds 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. 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 miles 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 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. 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 be crushed to death by its own weight - a result of the effects of gravity.