Pygmy killer whale
Group of Pygmy killer whales. Source: Alison Cohan/NOAA
Contrary to its common name, the little-known Pygmy killer whale (scientific name: Feresa attenuata), is actually a member of the dolphin family. Until 1952, the Pygmy killer whale was only known from two skulls collected in the 19th century.While more specimens have been collected since, it remains one of the least known of the small cetaceans. It is also known as the Slender blackfish.
Like its name, the Pygmy killer whale has been known to be quite aggressive. Both in captivity and in nature, this species has been seen attacking, killing, and eating other dolphins. In fact, in captivity, this dolphin has been known to attack its trainers, and even kill all other cetaceans that share the same tank. However, this dolphin is known to be shy around ships in their natural environment.
 Pygmy killer whale.Source: Pieter A. Folkens/Mammals of Texas-Online Edition |
 Comparison of an average size adult human to an adult Pygmy killer whale. Source: Chris Huh
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Scientific Classification Kingdom: Anamalia (Animals) |
Contents
Physical description
ThePygmy killer whalehas a slender, cigar-shaped body that tapers to the tail fin, with a round, blunt head that lacks the beak of many dolphin species. The pygmy killer whale is dark grey to black, with lighter sides and a dark cape that extends down the back.
This dolphin is very similar in appearance to the melon-headed whale and tothejuvenilefalse killer whale. From a distance, it is very difficult to tell these three apart. The shape of the head, the dorsal fin, and the flippers of pygmy killer whales, however,are different from the other two. The head of Feresa attenuata is rounded and lacks a beak. They have an underslung jaw and white lips, and usually a white patch on the tip of the lower jaw. The skull is asymmetrical and the right jaw is smaller and usually has one less tooth than the left jaw. The teeth are large and cone-shaped.
Pygmy killer whales have a sub-triangular, long based, high dorsal fin with a tip that points backward. The dorsal fin is located near the center of the body and lacks rigidity. The flippers of pygmy killer whales are moderate in length and have rounded tips.
Pygmy killer whales are not whale sized at all; rather, they are average sized dolphins and part of the family Delphinidae . An adult ranges in length from 2.1 to 2.6 meters and weighs between 110 and 170 kg.
Reproduction
Little is known about the reproduction of Feresa attenuata. It is believed that males are sexually mature when they are greater than 2.16 m in length, and females when they are greater than 2.21 m in length. The summer months are thought to be when most of the calves are born. Generally only one calf at a time is born to each adult female. The mother cares for and nurses her young until the calf reaches independence.
Behavior
The quick and lively pygmy killer whale is most commonly found in herds of 12 to 50 individuals, although great herds of 100 or more have also been encountered. They are known to be playful, having been observed riding the waves around the bow of a boat, tail slapping, leaping high out the water and spyhopping (raising the head and sometimes the upper body vertically out of the water). Pygmy killer whales can also be wary of boats and will cluster together when fleeing a disturbance. Their feeding habits are not well known, but the remains of small fish and cephalopods have been found in the stomachs of stranded pygmy killer whales and, in behaviour that lends a little truth to their name, they are suspected to occasionally chase, attack and even eat dolphins.
Pygmy killer whales are described as aggressive animals that have been seen snapping their jaws, beating their flippers and flukes on the surface of the water, and growling. In captivity, they elicit fear reactions from other cetaceans. They will charge, bite, and snap their jaws at other cetaceans as well as their trainers. They will often kill all other cetaceans that are in the tank with them. Though aggressive toward other animals, pygmy killer whales are shy of vessels.
Pygmy killer whales are believed to be non-migratory,however, little is known about their migratory habits.
Distribution
Worldwide range of the Pygmy killer whale. Source: IUCN Occurs in tropical and subtropical waters worldwide, generally not ranging north of 40 °N or south of 35 °S. Some countries they occur in include Comores, Kenya, Madagascar, Mauritius, Mediterranean Sea, Mozambique, North West Atlantic, Reunion, Seychelles, Somalia, Tanzania.
Habitat
Feresa attenuata is primarily a species of tropical waters, though it has been spotted in cooler waters off the west coast of Southern Africa andPeru. It prefers sub-tropical and tropical waters usually in deep water in the open oceans and is rarely found in closed water.
Predation and feeding habits
Pygmy killer whales are importantmembers of pelagic ecosystems. Specifically, they are significant predators of fish and cephalopods. Their feeding habits are not well known, but the remains of small fish and cephalopods have been found in the stomachs of stranded Pygmy killer whales. This diet includes squid, octopus, and large fish, e.g., tuna and dolphin fish. Also, in behavior that lends a little truth to their name, the Pygmy whale issuspected to occasionally chase, attack and even eat dolphins. Little is known about predators of pygmy killer whales, whose large size and aggressiveness makes them invulnerable to many predators, but not to large sharks or larger cetaceans, such as the Orca.
Conservation status
This species is naturally uncommon, and while the pygmy killer whale is not believed to be seriously threatened at present, its naturally low abundance means that even small takes could have a significant impact on local populations. This dolphin is listed on the IUCN Red List as Data Deficient.
Threats
While the pygmy killer whale is not believed to be seriously threatened at present, its naturally low abundance means that even small takes could have a significant impact on local populations. Pygmy killer whales are captured intentionally in fisheries in St Vincent and Indonesia, where the whale meat may be consumed, and the oil used for cooking and medicinal purposes. In Sri Lanka, pygmy killer whales are harpooned and used as bait in long-line fisheries for sharks, billfish and other oceanic fishes. Pygmy killer whales are also caught incidentally in many areas.
Also, this species, like beaked whales, is likely to be vulnerable to loud anthropogenic sounds, such as those generated by navy sonar and seismic exploration, and have been a part of multi-species unusual stranding events in Taiwan.
References and Further reading
- Feresa attenuata (Gray 1874) Pygmy killer whale, Encyclopedia of Life
- IUCN Red List (December, 2007)
- Donahue, M.A. and Perryman, W.L. (2002) Pygmy Killer Whale. In: Perrin, W.F., Würsug, B. and Thewissen, J.G.M. (Eds) Encyclopedia of Marine Mammals. Academic Press, San Diego, California and London, UK.
- CITES (December, 2007)
- Mills, G. and Hes, L. (1997) The Complete Book of Southern African Mammals. Struik Publishers, Cape Town.
- Jefferson, T.A., Leatherwood, S. and Webber, M.A. (1993) FAO Species Identification Guide: Marine Mammals of the World. FAO, Rome.
- CMS Species Factsheet (January, 2008)
- Reeves, R.R., Smith, B.D., Crespo, E.A. and Notarbartolo di Sciara, G. (2003) Dolphins, Whales and Porpoises: 2002–2010 Conservation Action Plan for the World’s Cetaceans. IUCN/SSC Cetacean Specialist Group, IUCN, Gland, Switzerland and Cambridge, UK.
- NatureServe (January, 2008)
- "CETACEA: Feresa attenuata (Pygmy Killer Whale)" (On-line). Accessed December, 1999
- "Plan-Endangered Species Program - Pygmy Killer Whale" (On-line). Accessed December, 1999
- "Pygmy Killer Whale" (On-line). Accessed December, 1999.
- Pygmy Killer Whale, Feresa attenuata" (On-line). Accessed December, 1999.
- "The Majestic Presence of the Whale- The Pygmy Killer Whale" (On-line). Accessed December, 1999
- Balcomb, K. 1987. The Whales of Hawaii. San Francisco, CA: The Marine Mammal Fund.
- Banks, R. C., R. W. McDiarmid, A. L. Gardner, and W. C. Starnes. 2003. Checklist of Vertebrates of the United States, the U.S. Territories, and Canada
- Banks, R. C., R. W. McDiarmid, and A. L. Gardner. 1987. Checklist of Vertebrates of the United States, the U.S. Territories, and Canada. Resource Publication, no. 166. 79
- Felder, D.L. and D.K. Camp (eds.), Gulf of Mexico–Origins, Waters, and Biota. Biodiversity. Texas A&M Press, College Station, Texas.
- Gray, 1875. J. Mus. Godeffroy. Hamburg, 8:184.
- IUCN (2008) Cetacean update of the 2008 IUCN Red List of Threatened Species.
- Jefferson, T.A., S. Leatherwood and M.A. Webber. 1993. Marine mammals of the world. FAO Species Identification Guide. Rome. 312 p.
- Keller, R.W., S. Leatherwood & S.J. Holt (1982). Indian Ocean Cetacean Survey, Seychelle Islands, April to June 1980. Rep. Int. Whal. Commn 32, 503-513.
- Mead, James G., and Robert L. Brownell, Jr. / Wilson, Don E., and DeeAnn M. Reeder, eds. 2005. Order Cetacea. Mammal Species of the World: A Taxonomic and Geographic Reference, 3rd ed., vol. 1. 723-743
- Perrin, W. (2010). Feresa attenuata Gray, 1874. In: Perrin, W.F. World Cetacea Database. Accessed through: Perrin, W.F. World Cetacea Database on 2011-02-05
- Rice, Dale W. 1998. Marine Mammals of the World: Systematics and Distribution. Special Publications of the Society for Marine Mammals, no. 4. ix + 231
- Ridgway, S., R. Harrison. 1994. Handbook of Marine Mammals. San Diego, CA: Academic Press Inc..
- Tinker, S. 1988. Whales of the World. Honolulu, Hawaii: Bess Press, Inc..
- UNESCO-IOC Register of Marine Organisms
- Wilson, Don E., and DeeAnn M. Reeder, eds. 1993. Mammal Species of the World: A Taxonomic and Geographic Reference, 2nd ed., 3rd printing. xviii + 1207
- Wilson, Don E., and F. Russell Cole. 2000. Common Names of Mammals of the World. xiv + 204
- Wilson, Don E., and Sue Ruff, eds. 1999. The Smithsonian Book of North American Mammals. xxv + 750
- van der Land, J. (2001). Tetrapoda, in: Costello, M.J. et al. (Ed.) (2001). European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification. Collection Patrimoines Naturels, 50: pp. 375-376
Elements of this article were researched by a student at Texas Tech University participating in the Encyclopedia of Earth's (EoE) Student Science Communication Project. The project encourages students in undergraduate and graduate programs to write about timely scientific issues under close faculty guidance. All articles have been reviewed by internal EoE editors, and by independent experts on each topic.
