A Blue whale's tongue weighs around 2.7 metric tons (3.0 short tons) and, when fully expanded, its mouth is large enough to hold up to 90 metric tons (99 short tons) of food and water.
Despite the size of its mouth, the dimensions of its throat are such that a blue whale cannot swallow an object wider than a beach ball.
Its heart weighs 600 kilograms (1,300 lb) and is the largest known in any animal.
A blue whale's aorta is about 23 centimetres (9.1 in) in diameter.
During the first seven months of its life, a blue whale calf drinks approximately 400 litres (100 U.S. gallons) of milk every day.
Blue whale calves gain weight quickly, as much as 90 kilograms (200 lb) every 24 hours. Even at birth, they weigh up to 2,700 kilograms (6,000 lb)—the same as a fully grown hippopotamus.
Feeding
Blue whales feed almost exclusively on krill, though they also take small numbers of copepods.[28] The species of this zooplankton eaten by blue whales varies from ocean to ocean. In the North Atlantic, Meganyctiphanes norvegica, Thysanoessa raschii, Thysanoessa inermis and Thysanoessa longicaudata are the usual food;in the North Pacific, Euphausia pacifica, Thysanoessa inermis, Thysanoessa longipes, Thysanoessa spinifera, Nyctiphanes symplex and Nematoscelis megalops; and in the Antarctic, Euphausia superba, Euphausia crystallorophias and Euphausia valentin.
An adult blue whale can eat up to 40 million krill in a day.[35] The whales always feed in the areas with the highest concentration of krill, sometimes eating up to 3,600 kilograms (7,900 lb) of krill in a single day.[28] This daily calorie requirement of an adult blue whale is in the region of 1.5 million.[36]
Because krill move, blue whales typically feed at depths of more than 100 metres (330 ft) during the day and only surface-feed at night. Dive times are typically 10 minutes when feeding, though dives of up to 20 minutes are common. The longest recorded dive is 36 minutes[37]. The whale feeds by lunging forward at groups of krill, taking the animals and a large quantity of water into its mouth. The water is then squeezed out through the baleen plates by pressure from the ventral pouch and tongue. Once the mouth is clear of water, the remaining krill, unable to pass through the plates, are swallowed. The blue whale also incidentally consumes small fish, crustaceans and squid caught up with krill.[38][39]
Life history
A juvenile blue whale with its motherMating starts in late autumn and continues to the end of winter.[40] Little is known about mating behaviour or breeding grounds. Females typically give birth once every two to three years at the start of the winter after a gestation period of ten to twelve months.[40] The calf weighs about 2.5 metric tons (2.8 short tons) and is around 7 metres (23 ft) in length. Blue whale calves drink 380–570 litres (100–150 U.S. gallons) of milk a day. Weaning takes place for about six months, by which time the calf has doubled in length. Sexual maturity is typically reached at eight to ten years, by which time males are at least 20 metres (66 ft) long (or more in the Southern Hemisphere). Females are larger still, reaching sexual maturity at around the age of five, by which they are about 21 metres (69 ft) long.
Scientists estimate that blue whales can live for at least 80 years;[24][40][41] however, since individual records do not date back into the whaling era, this will not be known with certainty for many years. The longest recorded study of a single individual is 34 years, in the north-east Pacific.[37] The whales' only natural predator is the Orca.[42] Studies report that as many as 25% of mature blue whales have scars resulting from Orca attacks.[24] The mortality rate of such attacks is unknown.
Blue whale strandings are extremely uncommon, and, because of the species' social structure, mass strandings are unheard of.[43] However, when strandings do occur, they can become the focus of public interest. In 1920, a blue whale washed up near Bragar on the Isle of Lewis in the Outer Hebrides of Scotland. It had been shot in the head by whalers, but the harpoon had failed to explode. As with other mammals, the fundamental instinct of the whale was to try to carry on breathing at all costs, even though this meant beaching to prevent itself from drowning. Two of the whale's bones were erected just off a main road on Lewis and remain a tourist attraction.[44]
Estimates made by Cummings and Thompson (1971) suggest that source level of sounds made by blue whales are between 155 and 188 decibels when measured relative to a reference pressure of one micropascal at one metre.[45][46] All blue whale groups make calls at a fundamental frequency of between 10 and 40 Hz; the lowest frequency sound a human can typically perceive is 20 Hz. Blue whale calls last between ten and thirty seconds. Blue whales off the coast of Sri Lanka have been repeatedly recorded making "songs" of four notes duration lasting about two minutes each, reminiscent of the well-known humpback whale songs. Researchers believe that as this phenomenon has not been seen in any other populations, it may be unique to the B. m. brevicauda (Pygmy) subspecies
The blue whale (Balaenoptera musculus) is a marine mammal belonging to the suborder of baleen whales (called Mysticeti).[3] At up to 33 metres (108 ft) in length and 180 metric tons (200 short tons)[4] or more in weight, it is the largest animal ever known to have existed.[5]
Long and slender, the blue whale's body can be various shades of bluish-grey dorsally and somewhat lighter underneath.[6] There are at least three distinct subspecies: B. m. musculus of the North Atlantic and North Pacific, B. m. intermedia of the Southern Ocean and B. m. brevicauda (also known as the pygmy blue whale) found in the Indian Ocean and South Pacific Ocean. B. m. indica, found in the Indian Ocean, may be another subspecies. As with other baleen whales, its diet consists almost exclusively of small crustaceans known as krill.[7]
Blue whales were abundant in nearly all the oceans until the beginning of the twentieth century. For over 40 years, they were hunted almost to extinction by whalers until protected by the international community in 1966. A 2002 report estimated there were 5,000 to 12,000 blue whales worldwide[8], located in at least five groups. More recent research into the Pygmy subspecies suggests this may be an underestimate.[9] Before whaling, the largest population was in the Antarctic, numbering approximately 239,000 (range 202,000 to 311,000).[10] There remain only much smaller (around 2,000) concentrations in each of the North-East Pacific, Antarctic, and Indian Ocean groups. There are two more groups in the North Atlantic, and at least two in the Southern Hemisphere.
LS's Tip of the weekESSENTIAL OILS aren't essential unless you're an engine, a gearbox or a twatEdited 1 time(s). Last edit at 04/01/2010 09:41AM by LS..