Long-finned pilot whale
|Long-finned pilot whale|
|Size compared to an average human|
The long-finned pilot whale (Globicephala melas), recently erroneously dubbed the "Calderon dolphin", is one of the two species of cetacean in the genus Globicephala. It belongs to the oceanic dolphin family (Delphinidae), though its behavior is closer to that of the larger whales.
Like the orca, the long-finned pilot whale is really a dolphin. It has a bulbous forehead and is jet black or dark grey with grey or white markings on throat and belly and sometimes behind dorsal fin and eye. The dorsal fin is sickle shaped. The long flippers are about 15 to 20 percent of total body length. It is sometimes known as the pothead whale because the shape of its head reminded early whalers of black cooking pots. Females reach sexual maturity at about 3.7 m (12 ft) and 6 to 7 years of age. Males need about twice as long to reach sexual maturity at about 4.6 m (15 ft) and 12 years of age. An adult whale weighs 1.8 to 3.5 short tons (3,600 to 7,000 lb).
They are very social, family animals and may travel in groups of up to a hundred with a dominant female is mostly acting as a leader. These groups socialize with common bottlenose dolphins, Atlantic white-sided dolphins and Risso's dolphins. An adult whale needs about 50 kg (110 lb) of food a day, which consists mostly of cephalopods and to a lesser amount of fish. Pilot whales generally take several breaths before diving for a few minutes. Feeding dives may last over ten minutes. They are capable of diving to depths of 600 m (2,000 ft), but most dives are to a depth of 30–60 m (98–197 ft).
Gestation lasts approximately 12 to 15 months and calving occurs once every 3 to 5 years. Calves are generally 1.8 m (5 ft 11 in) at birth, and weigh about 102 kg (225 lb). The calf nurses for up to 27 months, with some evidence for longer lactation and extensive mother calf bonds. Most calves are born in the summer, though some calving occurs throughout the year. The males may compete for mates with fights involving butting, biting, and ramming. Mating also involves these activities, and some females carry scars from bites inflicted by males during the breeding season. Females have been observed to have calves as late as 55 years old, and lactate as late as 61. This evidence indicates that females may nurse their last calf until puberty (up to 10 years in males).
Communication and echolocation consist of a wide sound range from three to 18 kHz. These sounds are produced 14 to 40 times a minute.
Long-finned pilot whales are very active and can often be seen lobtailing and spyhopping. The younger ones also breach. Full grown females have been observed breaching, but this is very rare in adult males. Long-finned pilot whales often strand themselves on beaches – because they have strong family bonds, when one animal strands, the rest of the pod tends to follow. These whales have also been observed babysitting calves in the pod while the mother goes deep to feed. It has been observed in the Gulf of Saint Laurence where one female was babysitting up to three calves at a time.
Songs of long-finned pilot whales. The cracking noise is caused by echolocation.
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Range and distribution
They were once seen in the North Pacific, but became extinct possibly due to hunting. This was confirmed based on discovery of fossils in several locations of Japan, such as on Rebun Island and in Chiba Prefecture. Their biological niche after extinction has possibly been refilled by some of Short-finned pilot whales and became the population on today, known as the larger northern form. It is unknown whether this northern form will keep expand its range to colonize on the extinct species' historical ranges in the future.
The North Sea and Baltic Sea populations of the long-finned pilot whale are listed on Appendix II 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.
The long-finned pilot whale is also covered by the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas (ASCOBANS), the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS), the 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).
Whaling in the Faroe Islands in the North Atlantic has been practiced since about the time of the first Norse settlements on the islands. Around 950 Long-finned Pilot Whales (Globicephala melaena) are killed annually, mainly during the summer. The hunts, called grindadráp in Faroese, are non-commercial and are organized on a community level; anyone can participate. The hunters first surround the pilot whales with a wide semicircle of boats. The boats then drive the pilot whales slowly into a bay or to the bottom of a fjord. It is regulated by Faroese authorities but not by the International Whaling Commission as there are disagreements about the Commission's legal competency for small cetaceans. As of the end of November 2008 the chief medical officers of the Faroe Islands have recommended that pilot whales no longer be considered fit for human consumption because of the level of mercury in the whales.
Killed pilot wales in Hvalba.
- Mead, J. G.; Brownell, R. L., Jr. (2005). "Order Cetacea". In Wilson, D. E.; Reeder, D. M. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. pp. 723–743. ISBN 978-0-8018-8221-0. OCLC 62265494.
- 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). Globicephala melas. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 26 February 2009.
- "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.
- Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas. Ascobans.org. Retrieved on 2014-01-04.
- Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area. Accobams.org. Retrieved on 2014-01-04.
- Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region. Pacificcetaceans.org. Retrieved on 2014-01-04.
- Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia, Convention on Migratory Species page on the Long-finned pilot whale. UNEP/Convention on Migratory Species
- "Small Cetaceans". International Whaling Commission. 5 May 2004. Retrieved 21 July 2009.
- "Catch limits". International Whaling Commission. 1 September 2009. Retrieved 21 July 2009.
- MacKenzie, Debora (28 November 2008). "Faroe islanders told to stop eating 'toxic' whales". New Scientist. Retrieved 21 July 2009.
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