The blue whale
) is a marine mammal
belonging to thebaleen whales
At 30 metres (98 ft)
in length and 170 tonnes
or more in weight, it is the largest existing animal
and the heaviest that ever existed.
Long and slender, the blue whale's body can be various shades of bluish-grey dorsally and somewhat lighter underneath.
There are at least three distinctsubspecies
: B. m. musculus
of the North Atlantic and North Pacific, B. m. intermedia
of the Southern Ocean
and B. m. brevicauda
(also known as thepygmy 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
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 toextinction
until protected by the international community in 1966. A 2002 report estimated there were 5,000 to 12,000 blue whales worldwide,
located in at least five groups. More recent research into the Pygmy subspecies suggests this may be an underestimate.
Before whaling, the largest population was in the Antarctic, numbering approximately 239,000 (range 202,000 to 311,000).
There remain only much smaller (around 2,000) concentrations in each of the eastern North Pacific
, and Indian Ocean groups. There are two more groups in the North Atlantic
, and at least two in theSouthern Hemisphere