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

cetacean Cetacea (; , ) is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively c ...

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 Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

and to a lesser extent in the Indian and

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

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 States and federal territories of Malaysia, state of Malaysia. It is the largest among the 13 states, with an area almost equal to that of Peninsular Malaysia. Sarawak is located in East Malaysia in northwest Borneo, and is ...

Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda ...

. He donated it to the

British Museum The British Museum is a Museum, public museum dedicated to human history, art and culture located in the Bloomsbury area of London. Its permanent collection of eight million works is the largest in the world. It documents the story of human cu ...

. The skull remained unstudied until 1956 when Francis Fraser examined it and concluded that it was similar to species in both the genera '' Lagenorhynchus'' and '' Delphinus'' 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 () is a volcanic island in the Pacific Ocean administered by Costa Rica, approximately southwest of the Costa Rican mainland. It constitutes the 11th of the 15 districts of Puntarenas Canton of the Puntarenas Province, Province of ...

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. With a total land area of , it is the fourth-largest of Australia's states and territories by area, which in ...

and in

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

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 on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

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 The striped dolphin (''Stenella coeruleoalba'') is a dolphin found in temperate and tropical waters of all the world's oceans. It is a member of the oceanic dolphin family, Delphinidae. Taxonomy The striped dolphin, also known as the euphrosy ...

, 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 live on or near the bottom, and reef fish that are associated with coral reefs. ...

squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...

and

shrimp A shrimp (: shrimp (American English, US) or shrimps (British English, UK)) is a crustacean with an elongated body and a primarily Aquatic locomotion, swimming mode of locomotion – typically Decapods belonging to the Caridea or Dendrobranchi ...

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 located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

and

Uruguay Uruguay, officially the Oriental Republic of 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 the Río de la Plata to the south and the A ...

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

oceanographic Oceanography (), also known as oceanology, sea science, ocean science, and marine science, is the scientific study of the ocean, including its physics, chemistry, biology, and geology. It is an Earth science, which covers a wide range of top ...

conditions, such as

El Niño EL, El or el may refer to: Arts and entertainment Fictional entities * El, a character from the manga series ''Shugo Chara!'' by Peach-Pit * Eleven (''Stranger Things'') (El), a fictional character in the TV series ''Stranger Things'' * El, fami ...

. The species is also relatively common in the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

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

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

is a 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), 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 Cosmopolitan mammals Fauna of the Pantropical realm Fraser's dolphin Fraser's dolphin