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Bowhead Whale[1]
Size comparison against an average human
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Suborder: Mysticeti
Family: Balaenidae
Genus: Balaena
Species: B. mysticetus
Binomial name
Balaena mysticetus
Linnaeus, 1758
Bowhead whale range
Synonyms
  • Leiobalaena Eschricht, 1849

The Bowhead Whale (Balaena mysticetus), also known as Greenland Right Whale or Arctic Whale, is a baleen whale of the right whale family Balaenidae (some, like Herman Melville in his classic Moby Dick, think they are a sub-species of Right whale). A stocky dark-colored whale without a dorsal fin, it can grow to 20 meters (66 ft) in length. Estimated maximum weight of this thick-bodied species is 136 tonnes (134 LT; 150 ST), second only to the Blue Whale, although the Bowhead's maximum length is less than several other whales. The Bowhead spends its life in fertile Arctic waters, unlike other whales that migrate to feed or reproduce.

The Bowhead was an early whaling target. Its population was severely reduced before a 1966 moratorium. The population is estimated to be over 24,900 worldwide, down from an estimated 50,000 pre-whaling. The Bowhead is perhaps the longest-living mammal and has the largest mouth of any animal. [3]

Contents

Taxonomy

The Bowhead Whale was described by Carl Linnaeus in the 10th edition of his Systema Naturae (1758).[4] Balaena has remained a monotypic genus ever since. Leiobalaena, described by Eschricht in 1849, is a junior synonym.

The Bowhead Whale is an individual species, separate from the other right whales. It has always been recognized as such, and stands alone in its own genus as it has done since the work of Gray in 1821. There is, however, little genetic evidence to support this two-genera view. Indeed, scientists see greater differences between the members of Balaenoptera than between the Bowhead and the right whales. Thus, it is likely that all four species will be placed in one genus in some future review.[5]

It is thought that Balaena prisca, one of the five Balaena fossils from the late Miocene (~10 mya) to early Pleistocene (~1.5 mya), may be the same as the modern Bowhead Whale. Prior to these there is a long gap back to the next related cetacean in the fossil record, Morenocetus, which was found in a South American deposit dating back 23 million years.

Description

The Bowhead Whale is a robust-bodied, dark-colored animal with no dorsal fin and a strongly bowed lower jaw and narrow upper jaw. The baleen plates, exceeding three meters and the longest of the baleen whales, are used to strain tiny prey from the water. This whale has a massive bony skull which it uses to break the ice from beneath to breathe. Some Inuit hunters have reported whales surfacing through 60 cm (24 in) of ice in this method. The Bowhead may reach lengths of up to 20 m (66 ft) and females are larger than males. The blubber layer of whale flesh is thicker than in any other animal, averaging 43–50 cm (17–20 in). The longest reported length for a Bowhead, was 21.2 m (70 ft) for an unweighed giant caught off of Spitsbergen, Norway.[6]

Life history

Stamp showing drawing of mother and calf

The Bowhead is social and nonaggressive, and retreats under the ice when threatened.

Swimming

The Bowhead is a slow swimmer and usually travels alone or in small herds of up to six animals. Although it may stay below the water surface for as long as forty minutes in a single dive, it is not thought to be a deep diver.

The whales' behavior can also include breaching, tail slapping, and spyhopping.

Vocalizations

The Bowhead Whale is highly vocal and uses underwater sounds to communicate while traveling, feeding, and socializing. Some Bowheads make long repetitive songs that may be mating calls.

Reproduction

Sexual activity occurs between pairs and in boisterous groups of several males and one or two females.

Breeding has been observed from March through August; conception is believed to occur primarily in March. Reproduction can begin when a whale is 10 to 15 years old. Females produce a calf once every 3 to 4 years, after a 13-14 month pregnancy. The newborn calf is about 4.5 m (15 ft) long and approximately 1,000 kg (2,200 lb), growing to 9 m (30 ft) by its first birthday.

Because of their long lifespans, females are believed to go through menopause. Observations of very large animals without calves support this hypothesis.[7]

Lifespan

The lifespan of a Bowhead was once thought to be 60 to 70 years, similar to other whales. However, discoveries of antique ivory spear points in living whales in 1993, 1995, 1999, and 2007 triggered research based on structures in the whale's eye, leading to the reliable conclusion that at least some individuals reached 150–200 years old (another report claimed a 90 year old female was still fertile.)[8]

In May 2007, a 50 tonnes (49 LT; 55 ST) specimen caught off the Alaskan coast was discovered with the head of an explosive harpoon embedded deep under its neck blubber. Examination determined the 3.5 inches (89 mm) arrow-shaped projectile was manufactured in New Bedford, Massachusetts, a major whaling center, around 1890. This proof that it survived a similar hunt more than a century ago indicated that the whale's age was between 115 and 130 years old.[9][10][11]

Ecology

Range and habitat

The Bowhead Whale is the only baleen whale that spends its entire life in and around Arctic waters. The Alaskan population spends the winter months in the southwestern Bering Sea. The group migrates northward in the spring, following openings in the pack ice, into the Chukchi and Beaufort seas, hunting zooplankton such as copepods.

Population status

Two whaleboats beached in foreground, 5 rowed and 4 sailing whaleboats chasing/attacking 5 whales, two larger whaling ships nearby, and sun peeking around snow-covered mountain in background
Eighteenth century engraving showing Dutch whalers hunting Bowhead Whales in the Arctic

The Bowhead Whale has been hunted for blubber, meat, oil, bones, and baleen. It shares with right whales the attractive characteristics of slow swimming and floating after death. Before commercial whaling, there were over 50,000 Bowhead Whales in the north polar region (estimated).

Commercial whaling began in the 16th century, when the Basques hunted Bowhead Whales migrating south through the Strait of Belle Isle in the fall and early winter. In 1611, the first whaling expedition was sent to Spitsbergen, and by mid-century the population(s) there had practically been wiped out, forcing whalers to voyage into the "West Ice"—the pack ice off Greenland's east coast. By 1719, they had reached the Davis Strait, and by the first quarter of the 19th century Baffin Bay. In the North Pacific, commercial whaling began in the 1840s, and within two decades wiped out over 60 percent of the Bowheads.

Commercial whaling, the principal cause of the population decline, is over. The population off Alaska has increased since commercial whaling ceased. Alaska Natives continue to kill small numbers in subsistence hunts each year. This level of killing (25–40 animals annually) is not expected to affect the population's recovery. The population off Alaska's coast (also called the Bering-Chukchi-Beaufort stock) appears to be recovering but remained at about 10,500 animals as of 2001. The status of other populations is less well known. There were about 1,200 off West Greenland in 2006, while the Spitsbergen population may only number in the tens.

In March, 2008, Canada's Department of Fisheries and Oceans stated that previous estimates in the Eastern Arctic had undercounted, with a new estimate of 14,400 animals (r. 4,800-43,000).[12] These larger numbers correspond to the pre-whaling estimates, indicating that this population has recovered. However, should climate change break up more sea ice, they could be threatened by increased shipping traffic.[13]

The Bowhead is listed in Appendix I by CITES (that is, "threatened with extinction"). It is listed by the National Marine Fisheries Service as endangered under the auspices of the United States' Endangered Species Act. The IUCN Red List data is as follows:

Drawing of long backbone, 13 ribs (2 vestigial) large, curved upper and lower jawbones that occupy 1/3 of the body, 4 multi-jointed "fingers" inside pectoral fin and connecting bone, enclosed in body outline
Skeleton of a Bowhead Whale

Diet

Unlike most other baleen whales which primarily feed on concentrated shoals of prey species, it feeds in a manner similar to the Basking Shark by swimming forward with its mouths agape and continuously filtering water through its baleen plates. Thus, it specializes in much smaller prey such as copepods. Its mouth has a large upturning lip on the lower jaw that helps to reinforce and contain the baleen plates within its mouth, and prevents buckling or breakage of the plates due to the pressure of the water passing through them as it advances.

This is in contrast to the rorquals which have distendable ventral pleats that they fill with water containing prey, which is then pushed out and filtered through the baleen plates.

Predation

Its only predators are humans and the Orca. On rare occasions, the Bowheads are also attacked by sea lions.

See also

References

  1. ^ Mead, James G. and Robert L. Brownell, Jr (November 16, 2005). Wilson, D. E., and Reeder, D. M. (eds). ed. Mammal Species of the World (3rd edition ed.). Johns Hopkins University Press. pp. 723–743. ISBN 0-801-88221-4. http://www.bucknell.edu/msw3/browse.asp?id=14300005.  
  2. ^ 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. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 7 October 2008.
  3. ^ Guinness World Records (2007-11-14). "Whale of a time!". Guinness World Records. http://www.guinnessworldrecords.com/news/2007/11/071114.aspx. Retrieved 2009-06-04.  
  4. ^ (Latin) Linnaeus, C (1758). Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.. Holmiae. (Laurentii Salvii).. pp. 824. http://dz1.gdz-cms.de/index.php?id=img&no_cache=1&IDDOC=265100.  
  5. ^ Kenney, Robert D. (2002). "North Atlantic, North Pacific and Southern Right Whales". in William F. Perrin, Bernd Wursig and J. G. M. Thewissen. The Encyclopedia of Marine Mammals. Academic Press. pp. 806–813. ISBN 0-12-551340-2.  
  6. ^ Wood (1983). The Guinness Book of Animal Facts and Feats. Sterling Pub Co Inc. ISBN 978-0851122359.  
  7. ^ Rare Whales Can Live to Nearly 200, Eye Tissue Reveals
  8. ^ Bowhead Whales May Be the World's Oldest Mammals
  9. ^ John C. George, Jeffrey Bada, Judith Zeh, Laura Scott, Stephen E. Brown, Todd O'Hara, and Robert Suydam (1999). "Age and growth estimates of bowhead whales (Balaena mysticetus) via aspartic acid racemization". Can. J. Zool. 77 (4): 571–580.  
  10. ^ Netted whale hit by lance a century ago - Science - MSNBC.com
  11. ^ 19th-century weapon found in whale » Propeller
  12. ^ Eastern Arctic bowhead whales not threatened
  13. ^ [Laidre, Kristin. "Foraging Ecology of Bowhead Whales in West Greenland." Monster Jam. Northwest Fisheries Science Center, Seattle. 22 Jan. 2009.]

External links


Wikispecies

Up to date as of January 23, 2010

From Wikispecies

Taxonavigation

Main Page
Cladus: Eukaryota
Supergroup: Unikonta
Cladus: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Classis: Mammalia
Subclassis: Theria
Infraclassis: Placentalia
Superordo: Cetartiodactyla
Ordo: Cetacea
Subordo: Mysticeti
Familia: Balaenidae
Genus: Balaena
Species: B. mysticetus

Name

Balaena Linnaeus, 1758

Type species: B. mysticetus Linnaeus, 1758

Synonyms

  • Leiobalaena Eschricht, 1849

References

  • Balaena on Mammal Species of the World.
    Don E. Wilson & DeeAnn M. Reeder (editors). 2005. Mammal Species of the World. A Taxonomic and Geographic Reference (3rd ed).
  • Linnaeus: Systema Naturae, 10th ed., 1: 75.
  • Mammal Species of the World, A Taxonomic and Geographic Reference, 3rd edition, 2005 ISBN 0801882214

Vernacular names

English: Bowhead Whale, Bowhead, Arctic Whale, Greenland Right Whale

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