Pygmy beaked whale

Pygmy beaked whale
Size compared to an average human
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Ziphiidae
Genus: Mesoplodon
Species: Mesoplodon peruvianus
Binomial name
Mesoplodon peruvianus
Reyes, Mead, and Van Waerebeek, 1991
Pygmy beaked whale range

The pygmy beaked whale (Mesoplodon peruvianus), also known as the bandolero beaked whale, Peruvian beaked whale and lesser beaked whale, is the smallest of the mesoplodonts and one of the newest discoveries. There were at least two dozen sightings of an unknown beaked whale named Mesoplodon sp. A before the initial classification, and those are now believed to be synonymous with the species. The species was formally described in 1991, based on ten specimens obtained from Peru between 1976 and 1989, including a 3.72 m (12.2 ft) adult male as the type specimen. A specimen that stranded at Paracas, Peru in 1955 (first tentatively identified as Andrews' beaked whale) has since been identified as a pygmy beaked whale. Since 1987, there have been an additional 40 sightings of the species, for a total of 65 (as of 2001).[2]

Description

The body of the pygmy beaked whale is the rather typical spindle shape of the genus, although the tail is unusually thick. The melon is somewhat bulbous and slopes down into a rather short beak. The mouthline in males has a very distinct arch with two teeth protruding slightly from the gum line before the apex. The coloration is typically dark gray on the top and lighter below, especially on the lower jaw, throat, and behind the umbililicus. Males may have a distinct pale "chevron" patterns on their backs. The size for this species in only around 4 meters (13 feet) long in mature animals, and around 1.6 meters (5.2 ft) when born.

Population and distribution

This beaked whale has been recorded in the eastern tropical Pacific between Baja California and Peru through sightings and strandings. Further strandings have been recorded in Chile (29°15′S 71°26′W / 29.250°S 71.433°W / -29.250; -71.433) and Monterey Bay (a 3.6 m (11.8 ft) female found at Salinas State Beach), and a fresh specimen in Humboldt County, CA in 1995, 2001, and 2012, respectively,[3] extending the species' range far to the north and south. Another specimen washed up in New Zealand, although this stranding is considered extralimital. No population estimates have been made.

Behavior

Little is known about the group behaviors of this whale, and small groups have been seen. Stomach contents reveal at least one specimen is a fish eater, as opposed to the squid normally eaten by the genus.

Conservation

This species may be quite vulnerable to gillnets in Peru, since scientists found six dead adults in a very small sample. However, there is not enough evidence to determine anything about the species.

Specimens

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 peruvianus. 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. ↑ Pitman RL, Lynn MS (2001). Biological observations of an unidentified mesoplodont whale in the eastern tropical Pacific and probable identity: Mesoplodon peruvianus. Mar. Mamm. Sci. 17: 648-657.
  3. ↑ Mesoplodon peruvianus stranding (STR13453), National Museum of Natural History Collections.

Sources

External links

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