Home »

Blue whale

The meaning of «blue whale»

The blue whale (Balaenoptera musculus) is a marine mammal belonging to the baleen whale parvorder Mysticeti. Reaching a maximum confirmed length of 29.9 metres (98 ft) and weighing up to 199 tonnes (196 long tons; 219 short tons), it is the largest animal known to have ever existed. The blue whale's long and slender body can be various shades of greyish-blue dorsally and somewhat lighter underneath.

The Society for Marine Mammalogy's Committee on Taxonomy currently recognizes four subspecies: B. m. musculus in the North Atlantic and North Pacific, B. m. intermedia in the Southern Ocean, B. m. brevicauda (the pygmy blue whale) in the Indian Ocean and South Pacific Ocean, B. m. indica in the Northern Indian Ocean. There is also a population in the waters off Chile that may constitute a fifth subspecies.

Blue whales are filter feeders; their diet consists almost exclusively of euphausiids (krill). They are generally solitary or gather in small groups and have no well-defined social structure other than mother-calf bonds. The fundamental frequency for blue whale vocalizations ranges from 8 to 25 Hz and the production of vocalizations may vary by region, season, behavior, and time of day.

The blue whale was once abundant in nearly all the Earth's oceans until the end of the 19th century. It was hunted almost to the point of extinction by whalers until the International Whaling Commission banned all blue whale hunting in 1966. The International Union for Conservation of Nature has listed blue whales as endangered as of 2018. It continues to face numerous threats, both man-made (ship strikes, pollution, ocean noise and climate change), and natural (killer whale predation).

Blue whales have long, slender mottled grayish-blue bodies, although they appear blue underwater.[3][4][5] The mottling pattern is highly variable. Individuals have a unique pigmentation pattern along the back in the region of the dorsal fin which can be used for the purpose of identification.[6][7][8]

Additional distinguishing features of the blue whale include a broad, flat head, which appears U shaped from above; 270–395 entirely black baleen plates on each side of their upper jaw; 60–88 expandable throat pleats; long, slender flippers; a small—up to 33 centimetres (13 in)— falcate dorsal fin positioned far back toward the tail; a thick tail stock; and a massive, slender fluke.[3][4][5][9][10]

Their pale underside can accumulate a yellowish coat of diatoms,[3][4][5] which historically earned them the nickname "sulphur bottom".[11][12] The blue whale's two blowholes create a tall, columnar spray, which can be seen 9.1–12.2 metres (30–40 ft) above the water's surface.[3][5][10]

The blue whale is the largest known animal to have ever existed.[13][3][14][15] The International Whaling Commission (IWC) whaling database reports 88 individuals longer than 30 metres (98 ft), including one of 33 metres (108 ft), but problems with how the measurements were taken suggest that any longer than 30.5 metres (100 ft) are suspect.[16] The Discovery Committee reported lengths up to 31 metres (102 ft);[17] however, the longest scientifically measured individual blue whale was 30 metres (98 ft) from rostrum tip to tail notch.[18] Female blue whales are larger than males.[5][19] Hydrodynamic models suggest a blue whale could not exceed 108 ft (33 m) because of metabolic and energy constraints.[20] The highest recorded weight for the species is 199 tonnes (196 long tons; 219 short tons).[16]

Related Searches

Blue Whale ChallengeBlue whale penisBlue Whale of Catoosa
Blue Whale Clustered file systemBlue Whale (TV series)Blue Whale Harbour
Fire Island Pines, New YorkBlue Whale Jazz ClubBlue Whale Unit
© 2015-2021, Wikiwordbook.info
Copying information without reference to the source is prohibited!
contact us mobile version