Sowerby's Beaked Whale - Mesoplodon bidens

Taxonomy & Nomenclature

Scientific Name Mesoplodon bidens
Author (Sowerby, 1804)
Taxonomic Rank Species
Taxonomic # 180515
Common Names English: North Atlantic beaked whale
English: Sowerby's Beaked Whale
Current Standing valid
Taxonomic Parents Kingdom: Animalia
  Phylum: Chordata
    Subphylum: Vertebrata
      Class: Mammalia
        Subclass: Theria
          Infraclass: Eutheria
            Order: Cetacea
              Suborder: Odontoceti
                Family: Hyperoodontidae
                  Genus: Mesoplodon
Taxonomic Children
Synonyms (since 1950)
Taxonomic data is courtesy of the Integrated Taxonomic Information System (ITIS)
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Physical Description / Field Identification

Sowerby’s beaked whales have the typical Mesoplodon body shape, but tend to have a very long (for mesoplodonts) beak and a bulge on the forehead. The two teeth of adult males erupt from the middle of the lower jaw, and are visible outside the closed mouth, although they are not particularly large.

Coloration is not well known, but generally appears charcoal gray, with a lighter belly. White or light gray spots are common on the body of adults; however, young animals have less spotting. Males reach lengths of at least 5.5 m and females, 5.1 m. Newborns average 2.4 m.

Can be Confused With

Sowerby’s beaked whales can be easily confused with other species of Mesoplodon; even bulls would be difficult to distinguish from related species at sea. The limited distribution will help narrow the choices.

Distribution

These beaked whales are known only from the colder waters of the North Atlantic, from at least Massachusetts to Labrador in the west, and from Iceland to Norway in the east. The range is known to include the Baltic Sea, but not the Mediterranean. The North Sea appears to be the center of abundance. There is a single record from the Gulf of Mexico, but this may represent an extralimital wandering.

Ecology and Behavior

Almost nothing is known of the natural history of this species beyond what has been learned from strandings, which have involved singles and pairs. However, in several groups observed at sea off Nova Scotia, groups ranged in size from 3-10, and dives lasted 12-28 minutes. The breeding season appears to be late winter to spring.

Feeding and Prey

Sowerby’s beaked whales feed on squid and small fish.

Threats and Status

There is little specific information on the status or threats of this species; however, some are known to have been killed by hunters in Newfoundland. Sowerby’s beaked whales are currently ‘Data Deficient’ (IUCN) and ‘Not Listed’ (ESA).

Links

References

Dalebout, M. L. 2002. Species identity, genetic diversity, and molecular systematic relationships among the Ziphiidae (beaked whales). Ph.D. dissertation, University of Auckland, New Zealand.

Hooker, S.K. and R.W. Baird. 1999. Observations of Sowerby’s beaked whales, Mesoplodon bidens, in the Gully, Nova Scotia. Canadian Field-Naturalist 113:273-277.

Mead, J.G. 1989. Beaked whales of the genus Mesoplodon. pp. 349-430 in S.H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Vol. 4: River dolphins and the larger toothed whales. Academic Press.

Pitman, R.L. 2002. Mesoplodont whales Mesoplodon spp. pp. 738-742 in W.F. Perrin, B. Würsig and J.G.M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.

ITIS TSN180515
Status - ESA, U.S. FWS -
    -
Status - Red List, IUCN -
    DD (Global or one of the sub regions)
    DD (Global or one of the sub regions)
#records (spatial)191
#records (non-spatial)0
#datasets19
Year1914 - 2015
Latitude27.98 - 61.06
Longitude-74.26 - 3.14
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