To see photographs of the Blue Whale (Balaenoptera musculus) click here.
Blue Whale (Balaenoptera musculus)
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© 2002 Kelvin Aitken. Image © 2002 marinethemes.com/Mark Conlin.
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Blue Whales belong to
the Balaenopteridae or Rorqual family of whales.This is the largest living creature ever to inhabit this planet. While some salps (a jellyfish-like invertebrate) grow longer, nothing can compare to the length and bulk of the mighty Blue Whale. This animal grows to at least 33.5 meters and 190 tonnes. An human infant could crawl through its largest arteries while its heart, the size of a small car, can cope with the tremendous pressure differences exerted on its circulatory system as it dives, withstanding a potential 3 atmosphere variation between its snout at 30 meters and its tail at or near the surface. Three elephants could fit on its tongue. Newborn calves are 7 meters long and gain 90 kilograms per day off the 190 litres of rich milk supplied by its mother.
Blue Whales are found in all oceans from the tropics to polar waters. They are more common in feeding areas close to ice floes but can be found in any oceanic region and even close to land in some areas. Their numbers have been seriously depleted due to whaling activity and are now completely protected.
Blue Whales in the northern hemisphere are generally smaller than their southern kin but some southern groups have differences in baleen, body shape and size so that they have been split into a sub species called the Pygmy Blue Whale (Balaenoptera musculus brevicaudata).
Their common name comes from the blue-grey colouration which is speckled with lighter grey spots with the undersides of the fins are pale grey to white. They have also been called the Sulphur Bottom Whale due to the yellow colour of the belly of some whales that have a coating of yellowish diatoms accumulated from their polar feeding grounds.
Blue Whales have a long slender body, slender but wide flukes able to propel them at 30 km/hr, a minute dorsal fin set well back near the tail, a flat rounded U shaped rostrum with a single ridge running from near the twin blowholes almost to the tip of the snout and a mass of throat pleats running from the tip of the lower jaw to the navel.
Like all Rorqual whales the Blue Whale (Balaenoptera musculus) uses its baleen to sieve food from the mass of water and prey caught in its ballooning throat. It feeds on up to 8 tons of krill per day, supplementing this diet with other schooling crustaceans and squid, travelling enormous distances in search of its prey. The blow of a blue whale is awesome in size, height and sound. The massive but slender blow can reach 10 meters high and can be heard from far away.
Blue Whales vocalise to communicate with other pod members which may be many kilometres away and it is suspected that the calls can be used to map the sea bed for navigation purposes. Please read the details regarding Fin Whales and their use of sound which is very similar to the Blue Whale.