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False Killer Whale Pseudorca crassidens

The false killer whale is a mid-sized toothed whale (Odontocetes) that measures about 5.3 m long for males and 4.5 m for females. It is the second largest dolphin next to the killer whale (Boyd et al. 1998). It weighs up to 1360 kg. The false killer whale is a uniform charcoal grey almost black with slightly paler areas around the throat and chest and the ventral line (see Reeves et al. 2002 for an excellent description) and rounded dorsal fin. Not much is known about this species. False killer whales range widely in the ocean in all tropical and warm temperate waters (Reeves et al. 2002). In the Pacific Ocean, the false killer whale ranges from British Columbia to Chile east to Australia and the Sea of Japan. It is not known if it occurs in the central north Pacific or the temperate South Pacific Ocean. The false killer whale is highly social and gregarious - observations of stranded marine mammals are often this species. The accompanying photo is of a lone individual that likely lost its way and spent several years about the southern Strait of Georgia near Vancouver, Canada. It showed interest in boats and often accompanied them as they motored about Point Roberts and Horseshoe Bay (Baird et al. 1989).

False killer whales travel and forage in groups of 10 to 20 animals (Reeves et al. 2002). Large assemblages numbering the hundreds also occur. The whales sometimes form wide bands of individuals across the ocean presumably searching for schools of fish likely reflecting well developed cooperative hunting skills. These small whales will kill dolphins (Perryman and Foster 1980, Brown et al. 1966) and have attacked sperm whales (Palacios and Mate 1996) but they mostly eat fish and squid. False killer whales often occur with other species of marine mammal.

False killer whales have exceptional hearing and have performed best in echolocation discrimination (Thomas et al. 1990, Nachtigall et al. 1996). False killer whales utter ‘whistles’ in the 1.5-18 kHz frequency range and ‘clicks’ in the 25-130 kHz range (Kamminga and van Velden 1987, Thomas and Turl 1990).

False killer whales give birth infrequently and live many years. Gestation is 15 months and calves measure 1.75 m at birth. Females nurse their calves for up to two years. The sex ratio of stranded individuals is about equal (Wilson and Ruff 1999). This reproductive strategy is unusual among marine mammals most of which breed every few years and wean their calves after one year.
The false killer whale is an abundant widespread species. A few are taken for human consumption in the Caribbean and also as incidental catch by gillnet and long line fisheries, and purse seine fishery (Wilson and Ruff 1999).

False Killer Whale facts:

False Killer Whale Distribution & Migration

References

Baird, R.W., K.M. Langelier and P.J. Stacey. 1989. First records of false killer whales, Pseudorca crassidens, in Canada. Canadian Field-Naturalist 103:368-371.

Brown, D.H., D.K. Caldwell and M.C. Caldwell 1966. Observations on the behavior of wild and captive false killer whales, with notes on associated behavior of other genera of captive delphinids. Los Angeles County Museum of Natural History Contributions in Science 95:1-32.

Kamminga, C. and J. G. Van Velden. 1987. Investigations on cetacean sonar II. Acoustical similarities and differences in odontocete signals. Aquatic Mammals 82:41-62.

Nachtigall, P. E., W.W.L. Au, and J. Pawloski. 1996. Low-frequency hearing in three species of odontocetes. Journal of Acoustical Society of America 100:2611.

Palacios, D.M. and B.R. Mate. 1996. Attack by false killer whales (Pseudorca crassidnes) on sperm whales (Physeter macrocephalus) in the Galápagos Islands. Marine Mammal Science 12:582-587.

Perryman, W.L. and T. C. Foster. 1980. Preliminary report of predation by small whales, mainly the false killer whale, Pseudorca crassidens, on dolphins (Stenella spp. and Delphinus delphis) in the eastern tropical Pacific. NOAA Report LJ-80-05, La Jolla, California.

Thomas, J. A. and C. W. Turl. 1990. Echolocation characteristics and range detection threshold of a false killer whale Pseudorca crassidens. Pp. 321-334 in J. A. Thomas and R. A. Kastelein (eds.). Sensory abilities of cetaceans: Laboratory and field evidence. Plenum, New York.

Thomas, J. A., J. L. Pawloski and W. W.L. Au. 1990. Masked hearing abilities in a false killer whale Pseudorca crassidens. Pp. 395-404 in J. A. Thomas and R. A. Kastelein (eds.). Sensory abilities of cetaceans: Laboratory and field evidence. Plenum, New York.

Wilson, D. E. and S. Ruff 1999. Smithsonian book of North American mammals. UBC press, Vancouver.