Pseudorca crassidens (Owen,
English: False killer whale
German: Kleiner Schwertwal
Spanish: Orca falsa
Pseudorca crassidens © Wurtz-Artescienza
Despite its world-wide distribution throughout the tropics and
subtropics, the false killer whale (P. crassidens) is one
of the lesser-known large odontocetes. These are large members of
the delphinid family, adult males reaching 6 m, while adult females
reach 5 m in length. The skull is similar to that of Orcinus
orca, but the two species don't seem to be closely related.
The colour is largely black or dark grey, with a white blaze on
the ventral side between the flippers. The head is rounded, without
a beak, the body shape elongate, the dorsal fin falcate and positioned
in the middle of the back. In males, the melon protrudes farther
forward than in females (Baird, 2009). Body mass may reach up to
2,000 kg in males (Jefferson et al. 2008).
Currently, there are no recognized subspecies (Rice, 1998) although
Kitchener et al. (1990) found substantial differences in cranial
characters between false killer whales from Australia, Scotland
and South Africa. While genetic comparison of specimens from the
eastern North Pacific Ocean, the western North Pacific, Indian,
and Atlantic oceans indicates low genetic variability, there seems
to be a demographically isolated population with long-term fidelity
around the main Hawaiian Islands (Chivers et al. 2007; Baird et
Most of the distributional records and many of the data available
for the species are the result of strandings (Odell and McClune,
1999). P. crassidens generally does not range beyond 50°
latitude in either hemisphere (Jefferson et al. 1993) and is found
world-wide in tropical and warm-temperate waters. It ranges north
to Maryland, Scotland, Japan, Hawaii, and Alaska and south to Patagonia
in Argentina, Cape Province, South Australia, Tasmania, South Island
of New Zealand, Chatham Islands, and southern Chile (Taylor et al.
2008). Although there are numerous records of animals seen in cool
temperate waters, these appear to be outside the normal range. Wanderers
have been recorded as far afield as Norway and Alaska (Carwardine,
Distribution of Pseudorca crassidens: tropical,
subtropical and warm temperate waters,
mainly offshore (Taylor et al. 2008; © IUCN; enlarge
3. Population size
Although widely distributed, the species is not really abundant
anywhere. There is no estimate of global abundance or of global
or regional population trends (Baird, 2009; Taylor et al. 2008).
In the past, P. crassidens appears to have been relatively
common off the Japanese coast, and population estimates of 16,000
have been reported for the coastal waters of China and Japan (Odell
and McClune, 1999 and refs. therein). Abundance in the eastern tropical
Pacific has been estimated at 39,800 (CV=64%) (Wade and Gerrodette
The most recent data are for the USA EEZ: In the northern Gulf
of Mexico the pooled abundance estimate for 2003-2004 of 777 (CV=0.56)
(Mullin 2007) and for 1996-2001 of 1,038 (CV=0.71) are not significantly
different (P>0.05) (Waring et al. 2008). A recent study conducted
during 2000-2004 produced an estimate of 123 (CV=0.72) false killer
whales for the Hawaii insular stock (Baird et al. 2005). The Hawaii
pelagic stock (within the EEZ outside of 75 nm of the Main Hawaiian
Islands) is estimated at 484 (CV = 0.93) false killer whales. And
in the US EEZ of the Palmyra Atoll, a recent line transect survey
produced an estimate of 1,329 (CV = 0.65) individuals (Barlow and
Finally, there are several recent observations from other areas.
Johnston et al. (2008) recently observed 5 false killer whales in
the western tropical Pacific off American Samoa. Gannier (2002)
observed one false killer whale near the Marquesas Islands in French
Polynesia. Kiszka et al. (2007) observed 2 false killer whales around
Mayotte in the northern Mozambique Channel and Weir (2007) recently
observed the species off northern Angola.
4. Biology and Behaviour
Habitat: P. crassidens is mainly seen in deep, offshore
waters (and some semi-enclosed seas such as the Red Sea and the
Mediterranean) and sometimes in deep coastal waters. It seems to
prefer warmer temperatures (Carwardine, 1995). Off Hawaii, individuals
were only infrequently encountered, and while found in depths from
38 to 4,331 m, sighting rates were greatest in depths >3,000
m (Baird et al. 2008). With the exception of sightings from the
eastern tropical Pacific, data on distribution are lacking for most
oceanic areas (Odell and McClune, 1999, and refs. therein).
Behaviour: The false killer whale readily approaches boats
and is an exceptionally active and playful animal, especially for
its large size (Carwardine, 1995).
Schooling: Sightings of groups of 10-20 individuals are common
and group sizes as high as 300 have been reported, presumably forming
when food is abundant. Herd size in recent mass strandings ranged
from 28 to over 1,000 animals, and a mean herd size of 55 has been
reported from Japanese waters. Mass-stranded herds have about equal
numbers of males and females of various sizes. False killer whales
may associate with other species, e.g. bottlenose dolphins and other
small cetaceans, possibly indicating shared or overlapping feeding
grounds (Odell and McClune, 1999). Long-term bonds between individuals
have been documented in Hawaiian waters (Baird et al. 2008).
Reproduction: Both sexes seem to mature between 8 and 14
years of age and maximum age seems to be 57 years in males and 62
in females (Baird, 2009). No seasonality in breeding is known for
the false killer whale (Jefferson et al. 1993).
Food: Although false killer whales eat primarily fish and
cephalopods, they also have been known to attack small cetaceans
and, on one occasion, even a humpback whale (Jefferson et al. 1993).
Depending on location, stomach contents included salmon (Oncorhynchus
sp.), squid (Berryteuthis magister or Gonatopsis borealis),
sciaenid and carangid fish, bonito (Sarda sp.), mahi mahi
or dolphin-fish (Coryphaena hippurus), yellowfin tuna (Thunnus
albacares), yellowtail (Pseudosciana spp.), perch (Lateolabrax
japonicus), mackerel, herring and smelt (Odell and Miller McClune,
1999, and refs. therein).
Koen-Alonso et al. (1999) examined the stomachs of false killer
whales from both coasts of the Strait of Magellan, Chile. The most
important prey were the oceanic and neritic-oceanic squids Martialia
hyadesi and Illex argentinus, followed by the neritic
fish Macruronus magellanicus. The prey species were subantarctic,
with two antarctic species, abundant over the Patagonian shelf and
adjacent oceanic waters around Tierra del Fuego. There are reports
that Pseudorca fed on and chased other dolphins in the eastern
tropical Pacific during chase and backdown operations of tuna purse
seine fishing, a habit that has also been attributed to the pygmy
killer whale (Feresa
attenuata) (Odell and McClune, 1999, and refs. therein).
In an individual stranded on Gran Canaria the stomach contained
cephalopod beaks from six species, the most important by number
being Thysanoteuthis rhombus, Argonauta sp. and
ommastrephids. Most of the cephalopod species represented inhabit
the epipelagic zone (Hernandez-Garcia, 2002).
False killer whales maintained in captivity consume up to 4.3%
of their body mass per day, which amounts to between 5000 and 6000
kg annually (body mass up to 450 kg) (Kastelein et al. 2000).
Migration is not well documented, although it has been suggested
that closely related globicephalid whales including Globicephala,
Pseudorca and Grampus
species in the western North Pacific move from warmer, southern
waters in winter to cooler, northern waters in summer. Apparent
seasonal movements in the western North Pacific may be related to
prey distribution. False killer whales have been seen travelling
in line formation, and one large herd of about 300 individuals was
distributed over an area several km long and about one km wide.
Reported travelling speeds are 3-6 knots and as high as 10 knots
(Odell and McClune, 1999, and refs. therein).
The population around Hawaii seems to show strong site fidelity:
although individual movements of up to 283 km were documented, with
a large proportion of individuals moving among islands. Individuals
were resighted up to 20.1 yr after first being documented, showing
long-term fidelity to the islands. Resighting rates were high, with
an average of 76.8% of distinctive individuals within groups documented
on more than one occasion (Baird et al. 2008).
Direct catch: Pseudorca are occasionally taken in
Japan for food and at St. Vincent Island in the Caribbean for meat
and cooking oil (Jefferson et al. 1993; Odell and McClune, 1999).
In a molecular monitoring of 'whalemeat' markets in the Republic
of South Korea, false killer whale meat was detected. Significant
inconsistencies were found in the expected frequencies of products
from most species, including a large over-representation of false
killer whales (Baker et al. 2006).
Incidental catch: Incidental take of small numbers of false
killer whales in gill nets has occurred off northern Australia,
the Andaman Islands, the southern coasts of Brazil and in tuna purse
seines in the eastern tropical Pacific. Dolphin entrapment in tuna
purse seine nets may be providing artificial feeding opportunities
for Pseudorca on other marine mammals (Odell and McClune,
1999; Alves et al. 2002).
Yang et al. (1999) reported on by-catch rates in Chinese coastal
fisheries (trawl, gill and stow net) which may number in the hundreds
per year for P. crassidens alone. Between 1994 and 2006,
24 false killer whales were observed hooked or entangled in Hawaii-based
longline fisheries, with approximately 4-34% of all effort observed.
Fifteen additional unidentified cetaceans, which may have been false
killer whales based on the observer's descriptions, were also taken
(hooked or entangled) in this fishery (Forney and Kobayashi 2007).
The rate of mortality and serious injury to false killer whales
within the Palmyra Atoll EEZ in the Hawaii-based longline fishery
is estimated at 1.2 animals per year (Caretta et al. 2008).
There was 1 reported fisheries-related stranding of a false killer
whale in the Gulf of Mexico during 1999-2006 (Waring et al. 2008).
Killing: The largest documented fisheries interaction was
in the waters around Iki Island, Japan, where over 900 false killer
whales were killed in drive fisheries from 1965 to 1980 in an attempt
to reduce interactions with the yellowtail (Pseudosciaena
spp.) fishery (Jefferson et al. 1993; Odell and McClune, 1999).
Pollution: High levels of pesticides (DDE) and heavy metals
(mercury) were detected in stranded specimens, and one individual
had the remains of a plastic jug in its stomach (Odell and McClune,
1999 and refs. therein). Concentrations of butyltin (BT) and phenyltin
(PT) compounds of specimens stranded on the coasts of Thailand were
were higher than in other odontocetes: False killer whales feed
on squid and large pelagic fish containing higher concentrations
of organotin (OT) compounds and may thus be particularly concentrating
these compounds (Harino et al. 2007).
Noise pollution: Nachtigall et al. (2008) showed that false
killer whales have very acute hearing capabilities including an
active `automatic gain control' mechanism. This entails a high susceptibility
to marine noise pollution.
Range states (Taylor et al. 2008)
American Samoa; Anguilla; Antigua and Barbuda; Argentina; Aruba;
Australia; Bahamas; Bangladesh; Barbados; Belize; Benin; Bermuda;
Brazil; British Indian Ocean Territory; Brunei Darussalam; Cambodia;
Cameroon; Canada; Cape Verde; Cayman Islands; Chile; China; Cocos
(Keeling) Islands; Colombia; Congo; Congo, The Democratic Republic
of the; Cook Islands; Costa Rica; Côte d'Ivoire; Croatia;
Cuba; Denmark; Djibouti; Dominica; Dominican Republic; Ecuador;
Egypt; El Salvador; Equatorial Guinea; Fiji; France; French Guiana;
French Polynesia; Gabon; Gambia; Germany; Ghana; Gibraltar; Greece;
Grenada; Guadeloupe; Guam; Guatemala; Guinea; Guinea-Bissau; Guyana;
Haiti; Honduras; Hong Kong; India; Indonesia; Iran, Islamic Republic
of; Ireland; Israel; Italy; Jamaica; Japan; Jordan; Kenya; Kiribati;
Kuwait; Liberia; Madagascar; Malaysia; Maldives; Malta; Marshall
Islands; Martinique; Mauritania; Mexico; Micronesia, Federated States
of; Morocco; Mozambique; Myanmar; Namibia; Netherlands; Netherlands
Antilles; New Caledonia; New Zealand; Nicaragua; Nigeria; Niue;
Northern Mariana Islands; Norway; Oman; Pakistan; Palau; Panama;
Papua New Guinea; Peru; Philippines; Pitcairn; Portugal; Puerto
Rico; Qatar; Saint Helena; Saint Kitts and Nevis; Saint Lucia; Saint
Pierre and Miquelon; Saint Vincent and the Grenadines; Samoa; Sao
Tomé and Principe; Senegal; Sierra Leone; Singapore; Solomon
Islands; Somalia; South Africa; Spain; Sri Lanka; Suriname; Syrian
Arab Republic; Taiwan, Province of China; Tanzania, United Republic
of; Thailand; Timor-Leste; Togo; Tokelau; Tonga; Trinidad and Tobago;
Turkmenistan; Turks and Caicos Islands; United Arab Emirates; United
Kingdom; USA; Uruguay; Vanuatu; Venezuela; Viet Nam; Virgin Islands,
British; Virgin Islands, U.S.; Wallis and Futuna; Western Sahara;
P. crassidens is classified as "Data Deficient" by the
IUCN (Taylor et al. 2008). The species is not listed by CMS. Listed
in Appendix II of CITES .
See more recommendations for South American populations in the
Hucke-Gaete (2000) report in Appendix
1 and for southeast Asian populations in Perrin et al. (1996)
see Appendix 2.
· Alonso MK, Pedraza SN, Schiavini ACM, Goodall
RNP, Crespo EA (1999) Stomach contents of false killer whales (Pseudorca
crassidens) stranded on the coasts of the Strait of Magellan,
Tierra del Fuego. Mar Mamm Sci 15: 712-724
· Alves MDO, Meirelles ACOde, Barros HMDdo R, Silva CPN,
Campos AA (2002) First report of the occurrence of false killer
whale, Pseudorca crassidens (Cetacea: Delphinidae), at Ceara
State, Brazil. Arq Cienc Mar 35 :107-112
· Barid RW (2009) False Killer Whale - Pseudorca crassidens.
In: Encyclopedia of marine mammals (Perrin WF, Würsig B, Thewissen
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· Baird RW, Gorgone AM , Webster DL, McSweeney DJ, Durban
JW, Ligon AD, Salden DR, Deakos M (2005). False killer whales around
the Main Hawaiian Islands: An assessment of inter-island movements
and population size using individual photo-identification. Contract
Report JJ133F04SE0120 prepared for the Pacific Islands Fisheries
Science Center, National Marine Fisheries Service, 2570 Dole Street,
Honolulu, Hawaii, 96822. 24pp.
· Baird RW, Gorgone AM, McSweeney DJ, Webster DL, Salden
DR, Deakos MH, Ligon AD, Schorr GS, Barlow J, Mahaffy SD (2008)
False killer whales (Pseudorca crassidens) around the main
Hawaiian Islands: Long-term site fidelity, inter-island movements,
and association patterns. Mar Mamm Sci 24: 591-612
· Baker CS, Lukoschek V, Lavery S, Dalebout ML, Yong-un M,
Endo T, Funahashi N (2006) Incomplete reporting of whale, dolphin
and porpoise 'bycatch' revealed by molecular monitoring of Korean
markets. Anim Conserv 9: 474-482
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and density: Preliminary estimates for the PICEAS study area south
of Hawaii and new estimates for the US EEZ around Hawaii. Admin
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structure in eastern North Pacific false killer whales (Pseudorca
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· Forney KA, Kobayashi DR (2007) Updated Estimates of Mortality
and Injury of Cetaceans in the Hawaii-Based Longline Fishery, 1994-2005.
NOAA Technical Memorandum NMFS SWFSC. no. 412, 35 pp.
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Polynesia): distribution and relative abundance as obtained from
a small boat dedicated survey. Aquat Mamm 28: 198-210
· Harino H, Ohji M, Wattayakorn G, Adulyanukosol K, Arai
T, Miyazaki N (2007) Accumulation of Organotin Compounds in Tissues
and Organs of Stranded Whales Along the Coasts of Thailand. Arch
Environ Contam Toxicol 53: 119-125
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of a false killer whale (Pseudorca crassidens) stranded in Gran
Canaria (Canary Islands, Central East Atlantic). Bull Mar Sci 71:
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· Kastelein RA, Mosterd J, Schooneman NM, Wiepkema PR (2000)
Food consumption, growth, body dimensions, and respiration rates
of captive false killer whales (Pseudorca crassidens). Aquat
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Stomach contents of false killer whales (Pseudorca crassidens)
stranded on the coasts of the Strait of Magellan, Tierra del Fuego.
Mar Mamm Sci 15: 712-724.
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© Illustrations by Maurizio Würtz, Artescienza.
© Maps by IUCN.