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Description

The blue whale (Balaenoptera musculus) is a marine mammal belonging to the baleen whales (Mysticeti ).[3] At up to 29.9 metres (98 ft)[4] in length and with a maximum recorded weight of 173 tonnes (190 short tons )[4] and probably reaching over 181 tonnes (200 short tons), it is the largest animal known to have ever existed.[5] [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,[4] in at least five groups. The IUCN estimates that there are probably between 10,000 and 25,000 blue whales worldwide today.[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 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 . As of 2014, the Eastern North Pacific blue whale population had rebounded to nearly its pre-hunting population.[11]

Description

The blue whale (Balaenoptera musculus) is a marine mammal belonging to the baleen whales (Mysticeti ).[3] At up to 29.9 metres (98 ft)[4] in length and with a maximum recorded weight of 173 tonnes (190 short tons )[4] and probably reaching over 181 tonnes (200 short tons), it is the largest animal known to have ever existed.[5] [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,[4] in at least five groups. The IUCN estimates that there are probably between 10,000 and 25,000 blue whales worldwide today.[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 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 . As of 2014, the Eastern North Pacific blue whale population had rebounded to nearly its pre-hunting population.[11]