Chilean dolphin

Chilean Dolphin
Size comparison against an average human
Conservation status
Near Threatened (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Subclass:	Eutheria
Order:	Cetacea
Suborder:	Odontoceti
Genus:	Cephalorhynchus
Species:	C. eutropia
Binomial name
Cephalorhynchus eutropia Gray, 1846
Chilean Dolphin range

The Chilean Dolphin (Cephalorhynchus eutropia), also known as the Black Dolphin, is one of four dolphins in the Cephalorhynchus genus. The dolphin is only found off the coast of Chile, it is commonly referred to in the country as Tunina.^[1]

Physical description

The Chilean Dolphin is a small dolphin at around 170 cm in length, with a blunt head. These characteristics often make for incorrect identification as a porpoise. The Dolphin is thickly-shaped with its girth up to two-thirds its length. The dorsal fin and flippers are small in proportion to body size in comparison with other dolphins. The throat, underside and the closest part of the flippers to the body are white. The remainder of the body is a mix of greys. The Dolphin has 28-34 pairs of teeth in the upper jaw and 29-33 in the lower.

The Dolphin is normally sighted in small groups of around two to ten individuals, with some larger gatherings occasionally sighted.

Longevity, gestation and lactation periods are not known, but are believed to be similar in length to the more studied, and similar, Hector's and Commerson's Dolphins which have a gestation period of about ten months to one year and maximum longevity of twenty years.

Population and distribution

The population of the Chilean Dolphin, perhaps one of the least studied of all cetaceans, is not known with certainty. There may be as many as a few thousand individuals, although at least one researcher, Steve Leatherwood, has suggested that the population may be much lower (see also [1] for a survey of South American cetacean population with data on the Chilean Dolphin). Whatever its number, the Chilean Dolphin is endemic to the coast of Chile and thought not to migrate. The dolphin is seen over a wider interval of latitudes than other Cephalorhynchus species - from Valparaíso at 33° S to Cape Horn at 55° S. The species appears to prefer areas of shallow water (less than 200 m depth) and in particular enjoys fast-flowing tidal areas and mouths of rivers.

Conservation

The Chilean dolphin is listed on Appendix II^[2] Convention on the Conservation of Migratory Species of Wild Animals (CMS). It is listed on Appendix II^[2] as it has an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements.

Name

In the early part of the twentieth century the Chilean Dolphin was commonly known as the Black Dolphin. This was later agreed to be a poor choice of name. Most of the few individual specimens studied by scientists were either washed-up individuals whose skin had darkened due to exposure to air or live specimens seen at sea but only at a distance (and so appeared darker than they were). As more specimens were studied it became clear that the back of the dolphin was in fact a mixture of grey colours and that its underside was white. The scientific community are now universally agreed in naming the dolphin Chilean on account of its distribution along the coast of the country.

Pictures

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References

• Reeves, R.R., Crespo, E.A., Dans, Jefferson, T.A., Karczmarski, L., Laidre, K., O’Corry-Crowe, G., Pedraza, S., Rojas-Bracho, L., Secchi, E.R., Slooten, E., Smith, B.D., Wang, JY. & Zhou, K. (2008). Cephalorhynchus eutropia. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 06 March 2009.

• National Audubon Society: Guide to Marine Mammals of the World ISBN 0-375-41141-0
• Encyclopedia of Marine Mammals ISBN 0-12-551340-2

1. ^ Chilean Dolphin Spanish site promoting conservation and awareness of this species.^{[dead link]}
2. ^ ^{a b} "Appendix II" of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). As amended by the Conference of the Parties in 1985, 1988, 1991, 1994, 1997, 1999, 2002, 2005 and 2008. Effective: 5th March 2009.

External links

• Whale and Dolphin Conservation Society
• Whales & Dolphins web page
• yaqu pacha - Organization for the Conservation of South American Aquatic Mammals
• Convention on Migratory Species page on the Chilean dolphin