Balaenidae

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Balaenidae[1]
Right whale size.svg
Size compared to an average human
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Suborder: Mysticeti
Infraorder: Chaeomysticeti
Superfamily: Balaenoidea
Family: Balaenidae
Gray, 1821
Genera

Balaena
Eubalaena
Balaenella
Balaenula
Balaenotus
Idiocetus
Mesoteras
Morenocetus
Protobalaena

Balaenidae range map.png
Range of the Balaenidae species

Balaenidae /bəˈlnɨd/ is a family of whales of the suborder mysticete that contains two living genera. Historically, it is known as the right whale family, as it was thought to contain only species of right whales. Through most of the 20th Century, however, that became a much-debated (and unresolved) topic amongst the scientific community.[2] Finally, in the early 2000s, science reached a definitive conclusion: the bowhead whale, once commonly known as the Greenland right whale, was not in fact a right whale.[3] The family of Balaenids, therefore, comprises the right whales (genus Eubalaena), and in a genus all to its own, the very closely related bowhead whale (genus Balaena).[4][5]

Characteristics[edit]

Balaenids are large whales, with an average adult length of 15 to 17 metres (45–50 feet), and weighing 50-80 tonnes. Their principle distinguishing feature is their narrow, arched, upper jaw, which gives the animals a deeply curved jawline. This shape allows for especially long baleen plates. The animals utilise these by floating at or near the surface, and straining food from the water, which they then scrape off the baleen with their tongues - a feeding method that contrasts with those of the rorquals and the gray whale. Their diet consists of small crustaceans, primarily copepods, although some species also eat a significant amount of krill.[6]

Balaenids are also robustly built by comparison with the rorquals, and lack the grooves along the throat that are distinctive of those animals. They have exceptionally large heads in comparison with their bodies, reaching 40% of the total length in the case of the Bowhead Whale. They have short, broad, flippers, and lack a dorsal fin.

All species are at least somewhat migratory, moving into warmer waters during the winter, during which they both mate and give birth. Gestation lasts 10–11 months, results in the birth of a single young, and typically occurs once every three years.[6]

Taxonomy[edit]

References[edit]

  1. ^ Mead, J. G.; Brownell, R. L., Jr. (2005). "Order Cetacea". In Wilson, D. E.; Reeder, D. M. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. pp. 723–743. ISBN 978-0-8018-8221-0. OCLC 62265494. 
  2. ^ Müller, J. (1954). "Observations of the orbital region of the skull of the Mystacoceti" (PDF). Zoologische Mededelingen 32: 239–90. 
  3. ^ Reilly, S.B., Bannister, J.L., Best, P.B., Brown, M., Brownell Jr., R.L., Butterworth, D.S., Clapham, P.J., Cooke, J., Donovan, G.P., Urbán, J. & Zerbini, A.N. (2008). "'Balaena mysticetus'". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012.  "The taxonomy is not in doubt. ... Concerning common names, the species was once commonly known in the North Atlantic and adjacent Arctic as the Greenland Right Whale. However, the common name Bowhead Whale is now generally used for the species."
  4. ^ Bannister, John L. (2008). "Baleen Whales (Mysticetes)". In Perrin, W. F.; Wursig, B.; Thewissen, J. G. M. Encyclopedia of Marine Mammals. Academic Press. p. 80. ISBN 978-0-12-373553-9. Retrieved 20 May 2012. Although Rice believed that all right whales belong with the bowhead in the genus Balaena, recent genetic analysis have recognized three separate right whale species, in the genus Eubalaena: in the North Atlantic (E. glacialis); in the North Atlantic (E. japonica); and in the Southern Hemisphere (E. australis). 
  5. ^ Kenney, Robert D. (2008). "Box 1: Taxonomic Rules, J.E. Grey, and Right Whale Names". In Perrin, W. F.; Wursig, B.; Thewissen, J. G. M. Right Whales (Eubalaena glacialis, E. japonica, and E. australis). Encyclopedia of Marine Mammals. Academic Press. p. 963. ISBN 978-0-12-373553-9. Retrieved 20 May 2012. The study by Churchill (2007) now has provided the evidence to conclude that the three living right whale species do comprise a phylogenetic lineage distinct from the bowhead and are rightly classified into a separate genus. 
  6. ^ a b Gaskin, David E. (1984). Macdonald, D., ed. The Encyclopedia of Mammals. New York: Facts on File. pp. 230–235. ISBN 0-87196-871-1.