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False killer whale

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False killer whale[1]
Size compared to an average human
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Mammalia
Order:
Cetacea
Family:
Delphinidae
Genus:
Pseudorca

Reinhardt, 1862
Species:
P. crassidens
Binomial name
Pseudorca crassidens
(Owen, 1846)
False killer whale range

The false killer whale (Pseudorca crassidens) is a cetacean, and the third largest member of the oceanic dolphin family (Delphinidae). 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 (killer whale). Like the orca, the false killer whale attacks and kills other cetaceans. However, the two dolphin species are not closely related.

The false killer whale has not been extensively studied in the wild; much of the data about it has been derived by examining stranded animals.

The species is the only member of the Pseudorca genus.

Population and distribution

The false killer whale appears to have a widespread, if small, presence in temperate and tropical oceanic waters. They have been sighted in fairly shallow waters such as the Mediterranean Sea and Red Sea as well as the Atlantic Ocean (from Scotland to Argentina), the Indian Ocean (in coastal regions and around the Lakshwadweep islands) and the Pacific Ocean (from the Sea of Japan to New Zealand and the tropical area of the eastern side), and also in Hawaii. The eastern tropical Pacific is estimated to have in excess of 40,000 individuals and is probably the largest population.[citation needed]

A false killer whale and a bottlenose dolphin mated in captivity and produced a fertile calf.[3] The hybrid offspring has been called a "wholphin".

Description

The skull of a false killer whale.
Photo of one large and one small animal soaring into the air
False killer whale and bottlenose dolphin at the Enoshima Aquarium, Japan

The false killer whale is black with a grey throat and neck. It has a slender body with an elongated tapered head and 44 teeth. The dorsal fin is sickle-shaped and its flippers are narrow, short and pointed. The average size is around 4.9 m (16 ft). Females can reach a maximum known size 5.1 m (17 ft) in length and weigh 1,200 kg (2,600 lb), while the largest males can reach 6.1 m (20 ft) and weigh as much as 2,200 kg (4,900 lb).[4][5][6]

Human interaction

The false killer whale has not been hunted extensively, for example in the West Indies and Indonesia. In Japan, a large number are killed every year during the annual slaughter in Taiji.

Several public aquaria display false killer whales. For example, Okinawa Churaumi Aquarium in Japan displays false killer whales in the Okichan Theater.[7]

Recent evidence indicates that the local population of false killer whales in Hawaii has declined dramatically over the last 20 years. Five years of aerial surveys undertaken from 1993 through 2004 showed a steep decline in sighting rates. Group sizes of the largest groups documented in surveys were almost four times larger than the entire current population estimate.[8]

Beachings

The Flinders Bay beaching, 1986.

On 30 July 1986, a pod of 114 false killer whales became stranded at Town Beach, Augusta, in Flinders Bay, Western Australia. In a three day operation, co-ordinated by the Department of Conservation and Land Management, 96 of the whales were carried by volunteers on trucks to more sheltered waters, and then successfully guided out into the bay.[9][10]

On 2 June 2005, up to 140 (estimates vary) false killer whales were beached at Geographe Bay, Western Australia.[11] The main pod, which had been split into four separate strandings along the length of the coast, was successfully moved back to sea with only one death after the intervention of 1,500 volunteers, coordinated once again by the Department of Conservation and Land Management.

Just prior to sunrise on 30 May 2009, a pod of 55 false killer whales was discovered beached on a sandy beach at Kommetjie in South Africa (latitude 34° 8'3.98"S, longitude 18°19'58.22"E).[12] By 9 a.m. 50 or more volunteers had already arrived to help move the whales into the ocean. Many more volunteers came throughout the day to offer their services. Late morning a decision by the authorities asked all volunteers to stabilize the false killers whales on the beach. No further attempt was made to take the whales into the open sea. At approximately 4 p.m. after considerable debate by all the authorities present, the decision was made to initiate euthanasia by shooting the whales; approximately 44 whales were killed.

Conservation

The false killer whale is covered by the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas (ASCOBANS) and the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS). The species is further included in the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia (Western African Aquatic Mammals MoU) and the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MoU)

See also

References

  1. ^ Mead, J. G.; Brownell, R. L. Jr. (2005). "Order Cetacea". In Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 723–743. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. ^ Template:IUCN2008
  3. ^ "Whale-dolphin hybrid has baby wholphin". MSNBC. April 15, 2005. Retrieved 2009-11-12.
  4. ^ [1] (2011).
  5. ^ [2] (2011).
  6. ^ [3] (2011).
  7. ^ {http://oki-churaumi.jp/en/area/okityan-theater.html"
  8. ^ "Hawai‘i's false killer whales". Cascadia Research.
  9. ^ "Whale rescue in 1986 changed not just the people who were there". ABC. South West WA. 2011-06-07. Retrieved 2012-07-08.
  10. ^ "World watched as WA town saved the whales". The West Australian. Perth, WA. 2011-07-19. Retrieved 2012-07-08.
  11. ^ "Scores of whales stranded in western Australia A pod of up to 80 whales has become stranded on a beach in Western Australia, the second mass beaching in the country in three weeks". The Daily Telegraph. London. 2009-03-23. Retrieved 2010-05-02. {{cite news}}: horizontal tab character in |title= at position 48 (help)
  12. ^ Pitney, Nico (2009-05-30). "Whales Killed At Kommetjie In South Africa (VIDEO)". Huffingtonpost.com. Retrieved 2011-12-07.

Further reading

  • Heptner, V. G.; Nasimovich, A. A; Bannikov, Andrei Grigorevich; Hoffmann, Robert S, Mammals of the Soviet Union, Volume II, part 3 (1996). Washington, D.C. : Smithsonian Institution Libraries and National Science Foundation


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