Taxonomy & Nomenclature
Physical Description / Field Identification
Pygmy killer whales reach maximum proportions of 2.6 m and 225 kg, males being larger than females. Newborns are about 80 cm long. The body of the pygmy killer whale is slender; the head is rounded and has no beak. The color of the body is dark gray to black, with a prominent narrow cape that dips slightly below the dorsal fin, and a white to light gray ventral band that widens around the genitals. Also, the lips and snout tip are sometimes white. The upper jaw contains 8-11 pairs of teeth, and the lower jaw has 11-13 pairs.
Can be Confused With
Pygmy killer whales are most easily confused with melon-headed whales, and less commonly with false killer whales. Flipper shape and the contour of the cape are the best features to use in distinguishing pygmy killer and melon-headed whales (rounded tips in the pygmy killer whale, pointed tips in the melon-headed whale, and humps on the leading edge in the false killer whale). Additionally, its movements tend to be slow and lethargic compared to the melon-headed whale.
Distribution
This is a tropical/subtropical species that inhabits oceanic waters around the globe, generally not ranging north of 40°N or south of 35°S. They are rarely seen in shallow waters. The range of pygmy killer whales is poorly known.
Atlantic Ocean – Pygmy killer whales have been reported in the Bay of Biscay; in the waters off Senegal; off the coast of the southeast U.S.; in the Gulf of Mexico and the Caribbean; on the coasts of Veracruz, Mexico and Brazil; and in the southwest Atlantic.
Pacific Ocean – The pygmy killer whale has been sighted in the eastern tropical Pacific and along the coast of South America in Peruvian and Ecuadorian waters; in Hawaiian waters; and in the western Pacific including Sagami Bay, Japan and Thailand.
Indian Ocean – Pygmy killer whales have been seen in the Indian Ocean, including the Arabian Sea and in the waters near the Maldives and Sri Lanka.
Ecology and Behavior
Pygmy killer whales inhabit oceanic waters and there is little known of the biology of the pygmy killer whale. Groups generally contain 50 or fewer individuals, although herds of several hundred have been seen. Not much is known of the reproductive biology of this species.
Feeding and Prey
Little is known regarding the diet of pygmy killer whales, but they eat mostly fish and squid. They occasionally attack other dolphins, at least when the dolphins are involved in tuna fishery interactions in the eastern tropical Pacific.
Threats and Status
Main threats include:
• Fisheries bycatch
• Entanglement in debris/fishing gear
Pygmy killer whales have been killed both directly in harpoon and driftnet fisheries (Caribbean Islands, Sri Lanka, Indonesia) and incidentally in various types of fishing gear. This species does not appear to be particularly abundant anywhere that it has been sighted – it may be naturally rare.
The IUCN lists this species as ‘data deficient’, in that there is not enough data to evaluate its conservation status. In the United States, this species is not listed as an endangered species.
Links
References
Donohue, M.A. and W.L. Perryman. 2002. Pygmy killer whale Feresa attenuata. pp. 1009-1010 in W.F. Perrin, B. Würsig and J.G.M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.
Leatherwood, S., D. McDonald, W.P. Prematunga, P. Girton, A. Ilangaakoon and D. McBrearty. 1991. Records of the "blackfish" (killer, false killer, pygmy killer, and melon-headed whales) in the Indian Ocean. UNEP Marine Mammal Technical Report 3:33-65.
Ross, G.J.B. and S. Leatherwood. 1994. Pygmy killer whale Feresa attenuata Gray, 1874. pp. 387-404 in S.H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Volume 5: The first book of dolphins. Academic Press.
Van Waerebeek, K. and J.C. Reyes. 1988. First record of the pygmy killer whale, Feresa attenuata Gray, 1875 from Peru, with a summary of distribution in the eastern Pacific. Zeitschrift fur Saugetierkunde 53:253-255.
Williams, A.D., R. Williams and T. Brereton. 2002. The sighting of pygmy killer whales (Feresa attenuata) in the southern Bay of Biscay and their association with cetacean calves. Journal of the Marine Biological Association of the United Kingdom 82:509-511.
