The
blue whale (
Balaenoptera musculus) is a
marine mammal belonging to the
baleen whales (
Mysticeti).
[3] At 30 metres (98 ft)
[4] in length and 170
tonnes (190
short tons)
[5] or more in weight, it is the
largest existing animal and the heaviest that ever existed.
[6]
Long and slender, the blue whale's body can be various shades of bluish-grey dorsally and somewhat lighter underneath.
[7] 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.
[8]
Blue whales were abundant in nearly all the oceans on
Earth until the beginning of the twentieth century. For over a century, 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,
[9]located in at least five groups. More recent research into the Pygmy subspecies suggests this may be an underestimate.
[10] Before whaling, the largest population was in the Antarctic, numbering approximately 239,000 (range 202,000 to 311,000).
[11] There remain only much smaller (around 2,000) concentrations in each of the eastern North
Pacific,
Antarctic, and Indian Ocean groups. There are two more groups in the North
Atlantic, and at least two in the
Southern Hemisphere.
ref:
http://en.wikipedia.org/wiki/Blue_whale
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