Stejneger's beaked whale

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Stejneger's beaked whale
Size comparison against an average human
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Family: Ziphiidae
Genus: Mesoplodon
Species: Mesoplodon stejnegeri
Binomial name
Mesoplodon stejnegeri
True, 1885
Stejneger's Beaked Whale range

Stejneger's beaked whale (Mesoplodon stejnegeri), sometimes known as the Bering Sea beaked whale or the Saber-toothed whale, is a poorly-known member of the genus Mesoplodon inhabiting the northern North Pacific Ocean. Leonhard Hess Stejneger collected the type specimen (a beach-worn skull) on Bering Island in 1883, which provided the description by Frederick W. True in 1885. In 1904, the first complete skull (from an adult male that had stranded near Newport, Oregon) was collected, which confirmed the species' validity.[2] The most noteworthy characteristic of the males is the very large, saber-like teeth, hence the name.

Description

The body for this species is rather typical for a mesoplodont, long and tapering at both ends. The beak of the whale is of medium length, and the mouthline forms an arch, though much smoother than other species. The teeth of the males are much larger than those of most other mesoplodonts and point forwards and inwards right in front of the apex. Only Strap-toothed whale and the Spade-toothed whale have longer teeth. The coloration is overall dark gray to black on the body with light coloration below, and around the head giving it a "helmeted" appearance. The coloration darkens with age, but females have a light pattern on the bottom of the flukes that becomes more apparent with age. Like most species, scars occur on the males (from other males) and cookiecutter shark bites are present on both sexes. The length is at least 5.25 meters (17 feet 6 inches) for males and 5.5 meters (18 feet) for females. They are likely around 2.1 to 2.3 meters long (7 to 8 feet) when born.

Population and distribution

This is the northernmost species of beaked whale in the Pacific Ocean, ranging up into the Bering Sea. They are distributed along both sides of the Pacific to Miyagi Prefecture, Japan and southern California. They may migrate south in winter. As with most species of beaked whales, no population estimates have been made.

Behavior

The whales are typically found in groups of three to four and sometimes up to 15 animals in a very close group. The groups may have age and sex segregation. Adult males fight each other extensively, and some specimens have been found with healed jaw fractures.

Conservation

This species has been occasionally hunted in Japan in the past, and occasionally been caught in drift nets. It is uncertain how much this affects the population.

References

  1. ↑ Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L. (2008). Mesoplodon stejnegeri. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 24 March 2009. Database entry includes a brief justification of why this species is of data deficient.
  2. ↑ True, F.W. 1910. An account of the beaked whales of the family Ziphiidae in the collection of the United States National Museum, with remarks on some specimens in other American museums. Washington: Government Printing Office.

Sources

  • Encyclopedia of Marine Mammals. Edited by William F. Perrin, Bernd Wursig, and J.G.M Thewissen. Academic Press, 2002. ISBN 0-12-551340-2
  • Sea Mammals of the World. Written by Randall R. Reeves, Brent S. Steward, Phillip J. Clapham, and James A. Owell. A & C Black, London, 2002. ISBN 0-7136-6334-0

External links

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