Fraser's dolphin or the Sarawak dolphin (''Lagenodelphis hosei'') is a

cetacean Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel th ...

in the family

Delphinidae Oceanic dolphins or Delphinidae are a widely distributed family of dolphins that live in the sea. Close to forty extant species are recognised. They include several big species whose common names contain "whale" rather than "dolphin", such as the ...

found in deep waters in the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the conti ...

and to a lesser extent in the

Indian Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asia ...

and

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

Taxonomy

''Lagenodelphis hosei'' is species of the delphinid family, distinguished from other dolphins as a monotypic genus, ''Lagenodelphis''. In 1895, Charles E. Hose found a skull on a beach in

Sarawak Sarawak (; ) is a state of Malaysia. The largest among the 13 states, with an area almost equal to that of Peninsular Malaysia, Sarawak is located in northwest Borneo Island, and is bordered by the Malaysian state of Sabah to the northeast, ...

Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and e ...

. He donated it to the

British Museum The British Museum is a public museum dedicated to human history, art and culture located in the Bloomsbury area of London. Its permanent collection of eight million works is among the largest and most comprehensive in existence. It docum ...

. The skull remained unstudied until 1956 when

Francis Fraser Francis Fraser may refer to: *Francis Charles Fraser (1903–1978), cetologist *Frankie Fraser (1923–2014), English criminal *Francis Humphris Fraser (1833–1911), New Zealand politician *Francis Richard Fraser Sir Francis Richard Fraser (14 F ...

examined it and concluded that it was similar to species in both the genera '' Lagenorhynchus'' and ''

Delphinus Delphinus (Pronounced or ) is a small constellation in the Northern Celestial Hemisphere, close to the celestial equator. Its name is the Latin version for the Greek word for dolphin (). It is one of the 48 constellations listed by the 2n ...

'' but not the same as either. A new genus was created by simply merging these two names together. The specific name is given in Hose's honour. It wasn't until 1971 that the whole body of a Fraser's dolphin, as it was by then becoming known, was discovered. At that time washed-up specimens were found on

Cocos Island Cocos Island ( es, Isla del Coco) is an island in the Pacific Ocean administered by Costa Rica, approximately southwest of the Costa Rican mainland. It constitutes the 11th of the 13 districts of Puntarenas Canton of the Province of Puntare ...

in the eastern Pacific, in

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest o ...

and in

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring coun ...

Description

Fraser's dolphins are about long and weight at birth, growing to and by adulthood. They have a stocky build, a small fin in relation to the size of the body, as well as conspicuously small flippers. The

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

and beak are also shorter than other species of dolphin. The upper side is a gray-blue to gray-brown. A dirty cream-colored line runs along the flanks from the beak, above the eye, to the anus. There is a dark stripe under this line. The belly and throat are usually white, sometimes tinged pink. The lack of a prominent beak is a distinguishing characteristic of this dolphin. From a distance, however, it may be confused with the striped dolphin, which has a similar coloration and is found in the same regions. Fraser's dolphins swim quickly in large, tightly-packed groups, numbering anywhere from 100 to 1,000 in number. Often porpoising, the groups chop up the water tremendously. The sight of seeing a large group fleeing from a fishing vessel has been reported as "very dramatic". It is also unique in having the smallest genitalia of any open sea dolphin. The species feeds on

pelagic fish Pelagic fish live in the pelagic zone of ocean or lake waters—being neither close to the bottom nor near the shore—in contrast with demersal fish that do live on or near the bottom, and reef fish that are associated with coral re ...

squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fittin ...

and

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are ref ...

found some distance below the surface of the water ( to ). Virtually no sunlight penetrates this depth, so feeding is carried out using echolocation alone.

Population and distribution

Though only accounted for relatively recently, the number of reported sightings has become substantial — indicating that the species may not be as rare as thought as recently as the 1980s. However the species is still not nearly as well understood as its more coastal cousins. No global population estimates exist. The dolphin is normally sighted in deep tropical waters; between 30°S and 20°N. The Eastern Pacific is the most reliable site for viewings. Groups of stranded dolphins have been found as far afield as

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

and

Uruguay Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...

. However these are regarded as anomalous and possibly due to unusual

oceanographic Oceanography (), also known as oceanology and ocean science, is the scientific study of the oceans. It is an Earth science, which covers a wide range of topics, including ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamic ...

conditions, such as

El Niño El Niño (; ; ) is the warm phase of the El Niño–Southern Oscillation (ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (approximately between the International Date ...

. The species is also relatively common in the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...

but less so in the rest of the Atlantic Ocean. The

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

is particularly known area for dolphin sightings, and is home to one of the larger populations of the Fraser's dolphin in the world.

Conservation

The Southeast Asian populations of Fraser's dolphins are listed on Appendix II 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: 5 March 2009. of the Convention on the Conservation of Migratory Species of Wild Animals (

CMS CMS may refer to: Computing * Call management system * CMS-2 (programming language), used by the United States Navy * Code Morphing Software, a technology used by Transmeta * Collection management system for a museum collection * Color manage ...

), since they have an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements. In addition, Fraser's dolphin is covered by Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region ( Pacific Cetaceans MoU) and the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia ( Western African Aquatic Mammals MoU).Western African Aquatic Mammals MoU
/ref>

Footnotes

References

External links

Voices in the Sea - Sounds of the Fraser's dolphin
{{Authority control

Fraser's dolphin Fraser's dolphin or the Sarawak dolphin (''Lagenodelphis hosei'') is a cetacean in the family Delphinidae found in deep waters in the Pacific Ocean and to a lesser extent in the Indian and Atlantic Oceans. Taxonomy ''Lagenodelphis hosei'' is sp ...

Cosmopolitan mammals Pantropical fauna