Tarea

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Blue whale
From Wikipedia, the free encyclopedia

Blue whale[1] |
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Adult blue whale from the eastern Pacific Ocean |
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Size compared to an average human |
Conservation status |

Endangered (IUCN 3.1)[2] |
Scientific classification |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Cetacea |Suborder: | Mysticeti |
Family: | Balaenopteridae |
Genus: | Balaenoptera |
Species: | B. musculus |
Binomial name |
Balaenoptera musculus
(Linnaeus, 1758) |
Subspecies |
* B. m. brevicauda Ichihara, 1966 * ?B. m. indica Blyth, 1859 * B. m. intermedia Burmeister, 1871 * B. m. musculus Linnaeus, 1758 |
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Blue whale range (in blue) |
The blue whale (Balaenopteramusculus) is a marine mammal belonging to the suborder of baleen whales (called Mysticeti).[3] At perhaps over 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 threedistinct 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 theIndian 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]
Bluewhales 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 bywhalers 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 maybe 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, andIndian Ocean groups. There are two more groups in the North Atlantic, and at least two in the Southern Hemisphere.
Contents [hide] *1 Taxonomy * 2 Description and behaviour * 2.1 Size * 2.2 Feeding * 2.3 Life history * 2.4 Vocalizations * 3 Population and whaling * 3.1 Hunting era * 3.2 Population and distribution today * 3.3 Threats other than hunting * 4 Museums * 5 Whale-watching * 6 Footnotes * 7 References * 8 External links |
-------------------------------------------------Taxonomy
See also: Evolution of cetaceans
Blue whales are rorquals (family Balaenopteridae), a family that includes the humpback whale, the fin whale, Bryde's whale, the sei whale and the minke whale.[3] The family Balaenopteridae is believed to have diverged from the other families of the suborder Mysticeti as long ago as the middle Oligocene. However, it is not known when the members of thosefamilies diverged from each other.
The blue whale is usually classified as one of eight species in the genus Balaenoptera; one authority places it in a separate monotypic genus, Sibbaldus,[11] but this is not accepted elsewhere.[1] DNA sequencing analysis indicates that the blue whale is phylogenetically closer to the sei whale (Balaenoptera borealis) and Bryde's whale(Balaenoptera brydei) than toother Balaenoptera species, and closer to the humpback whale (Megaptera) and the gray whale (Eschrichtius) than to the minke whales(Balaenoptera acutorostrata and Balaenoptera bonaerensis).[12][13] If further research confirms these relationships, it will be necessary to reclassify the rorquals.
There have been at least 11 documented cases of blue/fin hybrid adults in the wild. Arnason and...