Melon-headed Whale
Encyclopedia
The melon-headed whale is a cetacea
n of the oceanic dolphin
family
(Delphinidae). It is closely related to the pygmy killer whale
and pilot whale
, and collectively these dolphin
species are known by the common name blackfish. It is also related to the false killer whale
. The melon-headed whale is widespread throughout the world's tropical waters, although not often seen by humans because it prefers deep water
.
. Until 1966 it was classified in the genus Lagenorhynchus
. Scientists then gave it a unique genus
, 'Peponocephala'.
. Its head is a rounded cone giving the animal its common name. The body is more or less uniformly light grey except for a dark grey face – sometimes called the "mask". The flippers are long and pointed. The dorsal fin
is tall with a pointed tip – reminiscent of its cousin the Orca
. When viewed in profile its head is not as rounded as the Pygmy Killer
and this may aid identification.
This whale is capable of very fast swimming, particularly when startled. In flight, it often makes short low jumps clear of the sea surface, splashing lots water. Melon-heads usually gather in large numbers (at least 100 and possibly as many as 1,000 on rare occasions) and sometimes strand together.
The Melon-head weighs 10–15 kg (22–33.1 ) at birth and is 1 metres (3.3 ft) long. An adult grows up to 3 metres (9.8 ft) long and weighs over 200 kilograms (440.9 lb). The whales' lifespan is at least 20 years and probably more than 30 years for females.
Their primary diet is squid
.
Hawaiian melon-heads spend much of their daytime at the surface resting.
waters. Individuals have been sighted off the southern coast of Ireland
. Ordinarily, however, the Melon-head is found beyond the continental shelf
between 20° S and 20° N. Hawaii
and Cebu
, in the Philippines
, are good sites for seeing the whale because the continental shelf
there is narrow. Although no specific data exists, the species is unlikely to be migratory, in common with animals in its subfamily.
On February 10,2009, over 300 melon-headed whales were spotted off the shallow waters of Bataan
, in the Philippines
. Local residents and volunteers guided the dolphins back to deeper waters. Although no definite explanation has been provided for the dolphins' behaviour, it's been noted that two of the three dead dolphins had damaged ear drums.
In Hawaii
, group sizes are variable, ranging from a single animal to pods of 800, but typically they are found in relatively large groups (median = 287 individuals).There appear to be two Hawaiian populations a large, deep water group that moves frequently among the islands and a small, shallow water population that stays near the island of Hawaii. Melon-headed whales whales are closely related to false killer whales, short-finned pilot whales and pygmy killer whales. Hawaiian melon-heads spend much of their daytime at the surface resting.
Cetacea
The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea...
n of the oceanic dolphin
Oceanic dolphin
Oceanic dolphins are the members of the Delphinidae family of cetaceans. These marine mammals are related to whales and porpoises. They are found worldwide, mostly in the shallower seas of the continental shelves...
family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
(Delphinidae). It is closely related to the pygmy killer whale
Pygmy Killer Whale
The pygmy killer whale is a small, rarely seen cetacean of the oceanic dolphin family . It derives its common name from sharing some physical characteristics with the orca It is the smallest species that has "whale" in its common name. In fact, "killer" may be more apt in the case of the pygmy...
and pilot whale
Pilot whale
Pilot whales are cetaceans belonging to the genus Globicephala. There are two extant species, the long-finned pilot whale and the short-finned pilot whale . The two are not readily distinguished at sea and analysis of the skulls is the best way to tell the difference between them...
, and collectively these dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...
species are known by the common name blackfish. It is also related to the false killer whale
False Killer Whale
The False Killer Whale is a cetacean, and the third largest member of the oceanic dolphin family . It lives in temperate and tropical waters throughout the world. As its name implies, the False Killer Whale shares characteristics, such as appearance, with the more widely known Orca...
. The melon-headed whale is widespread throughout the world's tropical waters, although not often seen by humans because it prefers deep water
Bathyal zone
The bathyal zone or bathypelagic – from Greek βαθύς , deep – is that part of the pelagic zone that extends from a depth of 1000 to 4000 metres below the ocean surface. It lies between the mesopelagic above, and the abyssopelagic below. The average temperature hovers at about 39°F...
.
Taxonomy
Its inaccessibility limits scientiific understanding of this species. Most scientific data has come from mass strandingsWhale fall
Whale fall is the term used for a whale carcass that has fallen to the ocean floor. Whale falls were first observed in the 1980s, with the advent of deep-sea robotic exploration....
. Until 1966 it was classified in the genus Lagenorhynchus
Lagenorhynchus
Lagenorhynchus is a genus in the order Cetacea, traditionally containing six species:* white-beaked dolphin, Lagenorhynchus albirostris* Atlantic white-sided dolphin, Lagenorhynchus acutus...
. Scientists then gave it a unique genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
, 'Peponocephala'.
Description
The Melon-head has a body shape rather like a torpedoTorpedo
The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...
. Its head is a rounded cone giving the animal its common name. The body is more or less uniformly light grey except for a dark grey face – sometimes called the "mask". The flippers are long and pointed. The dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
is tall with a pointed tip – reminiscent of its cousin the Orca
Orca
The killer whale , commonly referred to as the orca, and less commonly as the blackfish, is a toothed whale belonging to the oceanic dolphin family. Killer whales are found in all oceans, from the frigid Arctic and Antarctic regions to tropical seas...
. When viewed in profile its head is not as rounded as the Pygmy Killer
Pygmy Killer Whale
The pygmy killer whale is a small, rarely seen cetacean of the oceanic dolphin family . It derives its common name from sharing some physical characteristics with the orca It is the smallest species that has "whale" in its common name. In fact, "killer" may be more apt in the case of the pygmy...
and this may aid identification.
This whale is capable of very fast swimming, particularly when startled. In flight, it often makes short low jumps clear of the sea surface, splashing lots water. Melon-heads usually gather in large numbers (at least 100 and possibly as many as 1,000 on rare occasions) and sometimes strand together.
The Melon-head weighs 10–15 kg (22–33.1 ) at birth and is 1 metres (3.3 ft) long. An adult grows up to 3 metres (9.8 ft) long and weighs over 200 kilograms (440.9 lb). The whales' lifespan is at least 20 years and probably more than 30 years for females.
Their primary diet is squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
.
Hawaiian melon-heads spend much of their daytime at the surface resting.
Population and distribution
The melon-headed whale lives far from shore in all the world's tropical and sub-tropical oceans. At the northern fringes of its range it may also be found in temperateTemperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
waters. Individuals have been sighted off the southern coast of Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
. Ordinarily, however, the Melon-head is found beyond the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
between 20° S and 20° N. Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
and Cebu
Cebu Island
Cebu is an island of the Philippines. It is the main island of Cebu Province at the center of the Visayan Islands, south of Manila.It lies to the east of Negros Island; to the east is Leyte and to the southeast is Bohol Island. It is flanked on both sides by the Cebu Strait and Tañon Strait...
, in the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, are good sites for seeing the whale because the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
there is narrow. Although no specific data exists, the species is unlikely to be migratory, in common with animals in its subfamily.
On February 10,2009, over 300 melon-headed whales were spotted off the shallow waters of Bataan
Bataan
Bataan is a province of the Philippines occupying the whole of the Bataan Peninsula on Luzon. The province is part of the Central Luzon region. The capital of Bataan is Balanga City and it is bordered by the provinces of Zambales and Pampanga to the north...
, in the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
. Local residents and volunteers guided the dolphins back to deeper waters. Although no definite explanation has been provided for the dolphins' behaviour, it's been noted that two of the three dead dolphins had damaged ear drums.
In Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, group sizes are variable, ranging from a single animal to pods of 800, but typically they are found in relatively large groups (median = 287 individuals).There appear to be two Hawaiian populations a large, deep water group that moves frequently among the islands and a small, shallow water population that stays near the island of Hawaii. Melon-headed whales whales are closely related to false killer whales, short-finned pilot whales and pygmy killer whales. Hawaiian melon-heads spend much of their daytime at the surface resting.
External links
- BBC: Hundreds of whales rescued in Philippines
- Aschettino, J.M. 2010. Population size and structure of melon-headed whales (Peponocephala electra) around the main Hawaiian Islands: evidence of multiple populations based on photographic data.] M.Sc. Thesis, Hawai‘i Pacific University. 117 pp.
- Baird, R.W., J.M. Aschettino, D.J. McSweeney, D.L. Webster, G.S. Schorr, S. Baumann-Pickering and S.D. Mahaffy. 2010. Melon-headed whales in the Hawaiian archipelago: an assessment of population structure and long-term site fidelity based on photo-identification.
- Southall, B.L., R. Braun, F.M.D. Gulland, A.D. Heard, R.W. Baird, S.M. Wilkin, and T.K. Rowles. 2006. Hawaiian melon-headed whale (Peponocephala electra) mass stranding event of July 3–4, 2004. NOAA Technical Memorandum NMFS-OPR-31.