Pygmy killer whale  (Feresa attenuata)

Contrary to its name, the little-known pygmy killer whale is actually a member of the dolphin family (2). Until 1952 the pygmy killer whale was only known from two skulls collected in the 19th century, and while more specimens have been collected since it remains one of the least known of the small cetaceans (2). It has a slender, cigar-shaped body that tapers to the tail fin, with a round, blunt head that lacks the beak of many dolphin species (2) (4). The pygmy killer whale is dark grey to black, with lighter sides and a dark ‘cape' that extends down the back. Its lips are edged with white and the moderately long flippers are rounded at the tips (2).

Occurs in tropical and subtropical waters worldwide, generally not ranging north of 40°N or south of 35°S (2) (5). Sightings of the pygmy killer whale have been most frequent in the eastern tropical Pacific, the Hawaiian Archipelago and off the coasts of Japan (2).

The pygmy killer whale inhabits deep, warm waters, and is rarely seen close to shore except around oceanic islands (6).

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 (2). They are known to be playful, having been observed riding the waves around the bow of a boat, leaping high out the water and spyhopping, the act of raising the head and sometimes the upper body vertically out of the water (2). Pygmy killer whales can also be wary of boats and will cluster together when fleeing a disturbance (4). 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 (2).

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 (7). Pygmy killer whales are captured intentionally in fisheries in St Vincent and Indonesia (2), where the whale meat may be consumed and the oil used for cooking and medicinal purposes (8), and 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 (2).

The pygmy killer whale is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that any international trade in this species should be carefully regulated (3). There are not known to be any other measures in place at present to protect this enigmatic and intriguing ocean mammal.

For further information on the pygmy killer whale see:

• 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.
• CMS Species Factsheet:
  www.cms.int/reports/small_cetaceans/data/F_attenuata/f_attenuata.htm

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