Page semi-protected
De Wikipedia, la enciclopedia libre
  (Redirigido desde Orca )
Saltar a navegación Saltar a búsqueda
"Orca" vuelve a dirigir aquí. Para otros usos, vea Orca (desambiguación) .
Para el episodio de Los Vengadores , vea Killer Whale (Los Vengadores) .

Orca [1]
Orca
Rango temporal: Plioceno a reciente[2]
Two killer whales jump above the sea surface, showing their black, white and grey colouration. The closer whale is upright and viewed from the side, while the other whale is arching backward to display its underside.
Orcas transitorias cerca de la isla Unimak , Islas Aleutianas orientales , Alaska
Diagram showing a killer whale and scuba diver from the side: The whale is about four times longer than a human, who is roughly as long as the whale's dorsal fin.
Tamaño en comparación con un humano de 1,80 metros (5 pies 11 pulgadas)
clasificación cientifica edit
Reino:Animalia
Filo:Chordata
Clase:Mammalia
Pedido:Artiodactyla
Infraorden:Cetáceos
Familia:Delphinidae
Género:Orcinus
Fitzinger , 1860 [5]
Especies:
Orca
Nombre binomial
Orcinus orca
A world map shows killer whales are found throughout every ocean, except parts of the Arctic. They are also absent from the Black and Baltic seas.
   Rango de Orcinus orca
Sinónimos
  • Delphinus orca Linnaeus, 1758
  • Gladiador Delphinus Bonnaterre, 1789
  • Gladiador orca (Bonnaterre, 1789)

La orca u orca ( Orcinus orca ) es una ballena dentada perteneciente a la familia de los delfines oceánicos , de la que es el miembro más grande. Es reconocible por su cuerpo negro con una parte inferior blanca y parches cerca de cada ojo. Las orcas tienen una dieta diversa, aunque las poblaciones individuales a menudo se especializan en tipos particulares de presas. Algunos se alimentan exclusivamente de peces, mientras que otros cazan mamíferos marinos como focas y otras especies de delfines. Se sabe que atacan a las crías de ballenas barbadas e incluso a las ballenas adultas. Las orcas son depredadores ápice , ya que ningún animal se alimenta de ellas.

Una especie cosmopolita , las orcas se pueden encontrar en todos los océanos del mundo en una variedad de ambientes marinos, desde las regiones árticas y antárticas hasta los mares tropicales, ausentes solo en los mares Báltico y Negro , y en algunas áreas del Océano Ártico . Son muy sociales ; algunas poblaciones se componen de grupos familiares matrilineales muy estables (vainas) que son los más estables de todas las especies animales. [6] Sus sofisticadas técnicas de caza y comportamientos vocales, que a menudo son específicos de un grupo en particular y se transmiten de generación en generación, se han descrito como manifestaciones de la cultura animal..

La Unión Internacional para la Conservación de la Naturaleza evalúa el estado de conservación de la orca como datos deficientes debido a la probabilidad de que dos o más tipos de orcas sean especies separadas . Algunas poblaciones locales se consideran amenazadas o en peligro debido al agotamiento de las presas, la pérdida de hábitat , la contaminación (por PCB ), la captura para parques de mamíferos marinos y los conflictos con la pesca humana . A finales de 2005, las orcas residentes del sur , que nadan en la Columbia Británica y el estado de Washingtonaguas, se colocaron en la lista de especies en peligro de extinción de EE . UU .

Las orcas salvajes no se consideran una amenaza para los humanos y nunca se ha documentado ningún ataque fatal contra humanos, pero ha habido casos de orcas cautivas que matan o hieren a sus cuidadores en parques temáticos marinos. Las orcas aparecen con fuerza en las mitologías de las culturas indígenas, y su reputación en diferentes culturas va desde ser el alma de los humanos hasta asesinas despiadadas. [7] [8]

Taxonomía y evolución

Esqueleto moderno de orca, Naturalis , Leiden

Orcinus orca es la única especie existente reconocida en el género Orcinus , y una de las muchas especies animales descritas originalmente por Carl Linnaeus en su histórica décima edición de Systema Naturae de 1758 . [9] Konrad Gessner escribió la primera descripción científica de una orca en su Piscium & aquatilium animantium natura de 1558, parte de la Historia animalium más grande , basada en el examen de un animal varado muerto en la bahía de Greifswald que había atraído mucho de interés local. [10]

La orca es una de las 35 especies de la familia de los delfines oceánicos , que apareció por primera vez hace unos 11 millones de años. El linaje de la orca probablemente se ramificó poco después. [11] Aunque tiene similitudes morfológicas con la orca falsa , la orca pigmea y las ballenas piloto , un estudio de las secuencias del gen del citocromo b indica que sus parientes más cercanos son los delfines del género Orcaella . [12] Sin embargo, un estudio más reciente (2018) coloca a la orca como un taxón hermano de Lissodelphininae, un clado que incluye a Lagenorhynchus yCephalorhynchus . [13]

Nombres comunes

Aunque el término "orca" se utiliza cada vez más, los científicos de habla inglesa utilizan con mayor frecuencia el nombre tradicional "ballena asesina". [14] El nombre del género Orcinus significa "del reino de los muertos", [15] o "perteneciente a Orcus ". [16] Los antiguos romanos originalmente usaban orca (pl. Orcae ) para estos animales, posiblemente tomando prestado el griego antiguo ὄρυξ ( óryx ), que se refería (entre otras cosas) a una especie de ballena. Desde la década de 1960, el uso común de "orca" ha crecido constantemente. [14] Como parte de la familia Delphinidae., la especie está más estrechamente relacionada con otros delfines oceánicos que con otras ballenas. [17]

A veces se les conoce como "pez negro", un nombre que también se usa para otras especies de ballenas. "Grampus" es un nombre anterior para la especie, pero ahora rara vez se usa. Este significado de "grampus" no debe confundirse con el género Grampus , cuyo único miembro es el delfín de Risso . [18]

Tipos

Los tres a cinco tipos de orcas pueden ser lo suficientemente distintos como para ser considerados diferentes razas , [19] subespecies o posiblemente incluso especies [20] (ver Problema de especies ). La UICN informó en 2008, "La taxonomía de este género necesita claramente una revisión, y es probable que O. orca se divida en varias especies diferentes o al menos subespecies durante los próximos años". [3] Aunque la gran variación en el carácter distintivo ecológico de los diferentes grupos de orcas complica la diferenciación simple en tipos, [21] la investigación de lacosta oeste de Canadá y Estados Unidos en las décadas de 1970 y 1980 identificaron los siguientes tres tipos:

  • Residente : Estas son las poblaciones más avistadas de las tres en las aguas costeras del Pacífico nororiental . La dieta de los residentes consiste principalmente en pescado [22] y, a veces , calamares , y viven en grupos familiares complejos y cohesionados llamados vainas. [23] Las mujeres residentes tienen las puntas de las aletas dorsales redondeadas que terminan en una esquina afilada. [24] Visitan las mismas áreas constantemente. Las poblaciones residentes de Columbia Británica y Washington se encuentran entre los mamíferos marinos más estudiados en todo el mundo. Los investigadores han identificado y nombrado más de 300 orcas en los últimos 30 años.[25]
  • Transitoria o de Bigg : La dieta de estas ballenas consiste casi exclusivamente en mamíferos marinos . [22] [24] Los transeúntes generalmente viajan en grupos pequeños, generalmente de dos a seis animales, y tienen lazos familiares menos persistentes que los residentes. [26] Los transitorios vocalizan en dialectos menos variables y menos complejos. [27] Las mujeres transitorias se caracterizan por tener aletas dorsales más triangulares y puntiagudas que las de los residentes. [24] El área gris o blanca alrededor de la aleta dorsal, conocida como la "mancha de silla de montar", a menudo contiene algo de color negro en los residentes. Sin embargo, los parches de transitorios en silla de montar son sólidos y uniformemente grises. [24]Los transeúntes deambulan ampliamente a lo largo de la costa; se han avistado algunos individuos tanto en el sur de Alaska como en California. [28] Los transitorios también se conocen como la orca de Bigg en honor al cetólogo Michael Bigg . El término se ha vuelto cada vez más común y eventualmente puede reemplazar la etiqueta transitoria. [29]
  • Mar adentro : una tercera población de orcas en el Pacífico nororiental fue descubierta en 1988, cuando un investigador de ballenas jorobadas las observó en aguas abiertas . Como sugiere su nombre, viajan lejos de la costa y se alimentan principalmente de cardúmenes . [30] Sin embargo, debido a que tienen aletas dorsales grandes, con cicatrices y melladas que se asemejan a las de los transeúntes cazadores de mamíferos, es posible que también coman mamíferos y tiburones. [31] [32] Se han encontrado principalmente en la costa oeste de la isla de Vancouver y cerca de Haida Gwaii . Las zonas costeras se congregan típicamente en grupos de 20 a 75, con avistamientos ocasionales de grupos más grandes de hasta 200. [33]Se sabe poco sobre sus hábitos, pero son genéticamente distintos de los residentes y transeúntes. Las costas marinas parecen ser más pequeñas que las demás, y las hembras se caracterizan por tener las puntas de las aletas dorsales redondeadas continuamente. [24]
Orcas tipo C en el Mar de Ross en el Océano Austral : el parche en el ojo se inclina hacia adelante.

Los transeúntes y los residentes viven en las mismas áreas, pero se evitan unos a otros. [34] [35] [36]

Otras poblaciones no han sido tan bien estudiadas, aunque en otros lugares se han distinguido orcas especializadas que se alimentan de peces y mamíferos. [37] Además, en el noroeste de Europa se han identificado poblaciones separadas de orcas "generalistas" (que comen peces y mamíferos) y "especializadas" (que comen mamíferos). [38] [39] Al igual que con los residentes y transeúntes, el estilo de vida de estas ballenas parece reflejar su dieta; Las orcas que se alimentan de pescado en Alaska [40] y Noruega [41] tienen estructuras sociales similares a las de los residentes, mientras que las orcas que se alimentan de mamíferos en Argentina y las Islas Crozet se comportan más como transeúntes. [42]

Se han documentado tres tipos en la Antártida . Dos especies enanas, llamadas Orcinus nanus y Orcinus glacialis , fueron descritas durante la década de 1980 por investigadores soviéticos, pero la mayoría de los investigadores de cetáceos son escépticos sobre su estado, y es difícil vincularlos directamente con los tipos descritos a continuación. [20]

Algunos ejemplos de variaciones en orcas
  • El tipo A parece una orca "típica", una forma grande, en blanco y negro, con un parche en el ojo blanco de tamaño mediano, que vive en aguas abiertas y se alimenta principalmente de ballenas minke . [20]
  • El tipo B es más pequeño que el tipo A. Tiene un gran parche en el ojo blanco. La mayoría de las partes oscuras de su cuerpo son de color gris medio en lugar de negras, aunque tiene un parche gris oscuro llamado "capa dorsal" [43] que se extiende desde la frente hasta justo detrás de la aleta dorsal. Las áreas blancas se tiñen ligeramente de amarillo. Se alimenta principalmente de focas . [20]
  • El tipo C es el más pequeño y vive en grupos más grandes que los demás. Su parche en el ojo está claramente inclinado hacia adelante, en lugar de ser paralelo al eje del cuerpo. Al igual que el tipo B, es principalmente de color blanco y gris medio, con una capa dorsal de color gris oscuro y manchas teñidas de amarillo. Su única presa observada es el bacalao antártico . [20]
  • El tipo D se identificó con base en fotografías de un varamiento masivo de 1955 en Nueva Zelanda y seis avistamientos en el mar desde 2004. El primer registro de video de este tipo se realizó en 2014 entre las islas Kerguelen y Crozet , [44] y nuevamente en 2017 fuera de la costa del Cabo de Hornos , Chile. [45] Es reconocible por su pequeño parche en el ojo blanco, aleta dorsal más estrecha y más corta de lo habitual, cabeza bulbosa (similar a una ballena piloto ) y dientes más pequeños. [46] Su distribución geográfica parece ser circumglobal en aguas subantárticas entre las latitudes 40 ° S y 60 ° S. Aunque su dieta no está determinada, es probable que incluya peces, según lo determinado por fotografías alrededor de los palangreros , donde las orcas Tipo D parecían estar depredando la austromerluza patagónica ( Dissostichus eleginoides ). [47] [48]

Los tipos B y C viven cerca del paquete de hielo , y las diatomeas en estas aguas pueden ser responsables de la coloración amarillenta de ambos tipos. [20] [49] Las secuencias de ADN mitocondrial apoyan la teoría de que estas son especies separadas recientemente divergentes. [50] Más recientemente, la secuenciación mitocondrial completa indica que los dos grupos antárticos que comen focas y peces deben ser reconocidos como especies distintas, al igual que los transitorios del Pacífico Norte, dejando a los demás como subespecies a la espera de datos adicionales. [51] Los métodos avanzados que secuenciaron todo el genoma mitocondrial revelaron diferencias sistemáticas en el ADN entre diferentes poblaciones. [52]Un estudio de 2019 de las orcas Tipo D también las encontró distintas de otras poblaciones y posiblemente incluso de una especie única. [47]

Durante mucho tiempo se pensó que las orcas que se alimentaban de mamíferos en diferentes regiones estaban estrechamente relacionadas, pero las pruebas genéticas han refutado esta hipótesis. [53]

Hay siete ecotipos identificados que habitan nichos ecológicos aislados . De los tres ecotipos de orcas en la Antártida, uno se alimenta de ballenas minke, el segundo sobre focas y pingüinos, y el tercero sobre peces. Otro ecotipo vive en el este del Atlántico norte, mientras que los tres ecotipos del noreste del Pacífico se denominan poblaciones transitorias, residentes y mar adentro descritas anteriormente. La investigación ha apoyado una propuesta para reclasificar las poblaciones que se alimentan de focas y peces de la Antártida y los transitorios del Pacífico Norte como especies distintas, dejando los ecotipos restantes como subespecies. La primera división en la población de orcas, entre los transitorios del Pacífico Norte y el resto, ocurrió hace aproximadamente 700.000 años. Tal designación significaría que cada nueva especie queda sujeta a evaluaciones de conservación separadas. [52]

Apariencia y morfología

Diferencias de aletas dorsales entre machos (frente) y hembras (fondo)
Anatomía interna de una mujer

Una ballena asesina típica tiene distintivamente un dorso negro, pecho y costados blancos, y una mancha blanca arriba y detrás del ojo. Los terneros nacen con un tinte amarillento o anaranjado, que se vuelve blanco. Tiene un cuerpo pesado y robusto [54] con una gran aleta dorsal de hasta 1,8 m (5 pies 11 pulgadas) de altura. [55] Detrás de la aleta, tiene un "parche de silla de montar" gris oscuro en la parte posterior. Las orcas antárticas pueden tener lomos de color gris pálido a casi blanco. Las orcas adultas son muy distintivas y rara vez se confunden con otras criaturas marinas. [56] Cuando se ven desde la distancia, los juveniles pueden confundirse con otras especies de cetáceos , como la falsa orca o el delfín de Risso . [57]

Los dientes de la orca son muy fuertes y sus mandíbulas ejercen un fuerte agarre; los dientes superiores caen en los espacios entre los dientes inferiores cuando la boca está cerrada. Los dientes medios y posteriores firmes mantienen a la presa en su lugar, mientras que los dientes frontales están ligeramente inclinados hacia adelante y hacia afuera para protegerlos de los movimientos bruscos. [58]

Las orcas son los miembros más grandes de la familia de los delfines. Los machos típicamente miden de 6 a 8 metros (20 a 26 pies) de largo y pesan más de 6 toneladas (5,9 toneladas largas; 6,6 toneladas cortas). Las hembras son más pequeñas, generalmente miden de 5 a 7 m (16 a 23 pies) y pesan alrededor de 3 a 4 toneladas (3,0 a 3,9 toneladas largas; 3,3 a 4,4 toneladas cortas). [59] Los terneros al nacer pesan alrededor de 180 kg (400 lb) y miden alrededor de 2,4 m (7,9 pies) de largo. [60] [61] El esqueleto de la orca tiene la estructura típica del delfínido, pero más robusto. [62] Su tegumento , a diferencia del de la mayoría de las otras especies de delfines, se caracteriza por una capa dérmica bien desarrollada con una densa red de fascículos de colágeno.fibras. [63]

Las aletas pectorales de la orca , análogas a las extremidades anteriores, son grandes y redondeadas, parecidas a paletas, siendo las de los machos significativamente más grandes que las de las hembras. Las aletas dorsales también exhiben dimorfismo sexual , con las de los machos de aproximadamente 1,8 m (5,9 pies) de altura, más del doble del tamaño de las hembras, con la aleta del macho más parecida a un triángulo isósceles alargado y alto , mientras que la de la hembra es más corta y más curva. . [64] Los hombres y las mujeres también tienen diferentes patrones de piel en blanco y negro en sus áreas genitales. [65] En el cráneo, los machos adultos tienen mandíbulas inferiores más largas que las hembras, así como crestas occipitales más grandes . [63]

Una orca individual a menudo se puede identificar por su aleta dorsal y su parche de silla. Las variaciones como mellas, raspaduras y desgarros en la aleta dorsal y el patrón de blanco o gris en el parche del sillín son únicas. Los directorios publicados contienen fotografías de identificación y nombres de cientos de animales del Pacífico Norte. La identificación fotográfica ha permitido contar la población local de orcas cada año en lugar de estimarse, y ha permitido una gran comprensión de los ciclos de vida y las estructuras sociales. [66]

De vez en cuando, una orca es blanca; se han visto en el norte del mar de Bering y alrededor de la isla de San Lorenzo , y cerca de la costa rusa . [67] [68] En febrero de 2008, una orca blanca fue fotografiada a 3,2 km (2,0 millas) del volcán Kanaga en las Islas Aleutianas . [67] [68] En 2010, el Far East Russia Orca Project (FEROP), co-fundado y codirigido por Alexander M. Burdin y Erich Hoyt , filmó a un hombre adulto apodado Iceberg . [69] [70]

Las orcas tienen buena vista por encima y por debajo del agua, excelente audición y buen sentido del tacto. Tienen habilidades de ecolocalización excepcionalmente sofisticadas , detectando la ubicación y las características de las presas y otros objetos en el agua emitiendo clics y escuchando ecos, [71] al igual que otros miembros de la familia de los delfines. La temperatura corporal media de la orca es de 36 a 38 ° C (97 a 100 ° F). [72] [73] Como la mayoría de los mamíferos marinos, las orcas tienen una capa de grasa aislante que varía de 7,6 a 10 cm (3,0 a 3,9 pulgadas) de espesor [72] debajo de la piel. El pulso es de aproximadamente 60 latidos por minuto cuando la orca está en la superficie, y desciende a 30 latidos / min cuando está sumergida. [74]

Rango y hábitat

Una ballena asesina salta del agua cuando nada, un comportamiento conocido como marsopa, en Hood Canal .
Orcas "tipo B" frente a la isla Georgia del Sur

Las orcas se encuentran en todos los océanos y en la mayoría de los mares. Debido a su enorme rango , número y densidad, la distribución relativa es difícil de estimar, [75] pero claramente prefieren latitudes más altas y áreas costeras a los ambientes pelágicos . [76] Las áreas que sirven como sitios de estudio importantes para la especie incluyen las costas de Islandia , Noruega , la Península Valdés de Argentina, las Islas Crozet , Nueva Zelanda y partes de la costa oeste de América del Norte, desde California hasta Alaska . [77]

Los estudios sistemáticos indican las densidades más altas de orcas (> 0,40 individuos por 100 km 2 ) en el Atlántico noreste alrededor de la costa noruega , en el Pacífico norte a lo largo de las Islas Aleutianas , el Golfo de Alaska y en el Océano Austral frente a gran parte de la costa. de la Antártida . [75] Se consideran "comunes" (0,20 a 0,40 individuos por 100 km 2 ) en el Pacífico oriental a lo largo de las costas de Columbia Británica , Washington y Oregón , en el Océano Atlántico Norte alrededor de Islandia y las Islas Feroe.. También se han reportado altas densidades, pero no cuantificadas, en el Pacífico Norte occidental alrededor del Mar de Japón , el Mar de Okhotsk , las Islas Kuriles , Kamchatka y las Islas Comandante y en el Hemisferio Sur frente al sur de Brasil y la punta del sur de África . Se informa que son comunes estacionalmente en el Ártico canadiense , incluida la bahía de Baffin entre Groenlandia y Nunavut , así como en Tasmania y la isla Macquarie . [75] Regularly occurring or distinct populations exist off Northwest Europe, California, Patagonia, the Crozet Islands, Marion Island, southern Australia and New Zealand.[39][75][78] The northwest Atlantic population of at least 67 individuals ranges from Labrador and Newfoundland to New England with sightings to Cape Cod and Long Island.[79]

Information for offshore regions and warmer waters is more scarce, but widespread sightings indicate that the killer whale can survive in most water temperatures. They have been sighted, though more infrequently, in the Mediterranean, the Arabian Sea, the Gulf of Mexico, Banderas Bay on Mexico's west coast and the Caribbean.[75] Over 50 individual whales have been documented in the northern Indian Ocean, including two individuals that were sighted in the Persian Gulf in 2008 and off Sri Lanka in 2015.[80] Those orcas may occasionally enter the Red Sea through the Gulf of Aden.[81] The modern status of the species along coastal mainland China and its vicinity is unknown. Recorded sightings have been made from almost the entire shoreline.[82] A wide-ranging population is likely to exist in the central Pacific, with some sightings off Hawaii.[83][84] Distinct populations may also exist off the west coast of tropical Africa,[85] and Papua New Guinea.[86] In the Mediterranean, killer whales are considered "visitors", likely from the North Atlantic, and sightings become less frequent further east. However, a small year-round population is known to exist in the Strait of Gibraltar, mostly on the Atlantic side.[87][88] Killer whales also appear to regularly occur off the Galápagos Islands.[89]

In the Antarctic, killer whales range up to the edge of the pack ice and are believed to venture into the denser pack ice, finding open leads much like beluga whales in the Arctic. However, killer whales are merely seasonal visitors to Arctic waters, and do not approach the pack ice in the summer. With the rapid Arctic sea ice decline in the Hudson Strait, their range now extends deep into the northwest Atlantic.[90] Occasionally, killer whales swim into freshwater rivers. They have been documented 100 mi (160 km) up the Columbia River in the United States.[91][92] They have also been found in the Fraser River in Canada and the Horikawa River in Japan.[91]

Migration patterns are poorly understood. Each summer, the same individuals appear off the coasts of British Columbia and Washington. Despite decades of research, where these animals go for the rest of the year remains unknown. Transient pods have been sighted from southern Alaska to central California.[93]

Population

Worldwide population estimates are uncertain, but recent consensus suggests a minimum of 50,000 (2006).[94][3][33] Local estimates include roughly 25,000 in the Antarctic, 8,500 in the tropical Pacific, 2,250–2,700 off the cooler northeast Pacific and 500–1,500 off Norway.[95] Japan's Fisheries Agency estimated in the 2000s that 2,321 killer whales were in the seas around Japan.[96][97]

Feeding

A killer whale skeleton

Killer whales are apex predators, meaning that they themselves have no natural predators. They are sometimes called the wolves of the sea, because they hunt in groups like wolf packs.[98] Killer whales hunt varied prey including fish, cephalopods, mammals, seabirds, and sea turtles.[99] Different populations or ecotypes may specialize, and some can have a dramatic impact on prey species.[100] However, whales in tropical areas appear to have more generalized diets due to lower food productivity.[84][85] Killer whales spend most of their time at shallow depths,[101] but occasionally dive several hundred metres depending on their prey.[102][103]

Fish

Tail-slapping in Vestfjorden, Norway
Resident (fish-eating) killer whales: The curved dorsal fins are typical of resident females.
Comparison of the size of an average orca and an average great white shark

Fish-eating killer whales prey on around 30 species of fish. Some populations in the Norwegian and Greenland sea specialize in herring and follow that fish's autumnal migration to the Norwegian coast. Salmon account for 96% of northeast Pacific residents' diet, including 65% of large, fatty Chinook.[104] Chum salmon are also eaten, but smaller sockeye and pink salmon are not a significant food item. Depletion of specific prey species in an area is, therefore, cause for concern for local populations, despite the high diversity of prey.[94] On average, a killer whale eats 227 kilograms (500 lb) each day.[105] While salmon are usually hunted by an individual whale or a small group, herring are often caught using carousel feeding: the killer whales force the herring into a tight ball by releasing bursts of bubbles or flashing their white undersides. They then slap the ball with their tail flukes, stunning or killing up to 15 fish at a time, then eating them one by one. Carousel feeding has only been documented in the Norwegian killer whale population, as well as some oceanic dolphin species.[106]

In New Zealand, sharks and rays appear to be important prey, including eagle rays, long-tail and short-tail stingrays, common threshers, smooth hammerheads, blue sharks, basking sharks, and shortfin makos.[107][108] With sharks, orcas may herd them to the surface and strike them with their tail flukes,[107] while bottom-dwelling rays are cornered, pinned to the ground and taken to the surface.[109] In other parts of the world, killer whales have preyed on broadnose sevengill sharks,[110] tiger sharks[111] and even small whale sharks.[112] Killer whales have also been recorded attacking and feeding on great white sharks,[31][113][114][115] and appear to target the liver.[31][114] Competition between killer whales and white sharks is probable in regions where their diets overlap.[116] The arrival of orcas in an area can cause white sharks to flee and forage elsewhere.[117] In False Bay,South Africa, a pair of male killer whales named Port and Starboard have become well-known in the region for contributing to the disappearance of the once abundant great white population.[118]

Mammals and birds

Feeding on a northern fur seal, Bogoslof Island, Alaska

Killer whales are sophisticated and effective predators of marine mammals. Thirty-two cetacean species have been recorded as prey, from observing orca feeding activity, examining the stomach contents of dead orcas, and seeing scars on the bodies of surviving prey animals. Groups even attack larger cetaceans such as minke whales, grey whales,[119][120] and, rarely, sperm whales or blue whales.[37][121][122][123] In cases where blue whales are attacked, as many as 50 killer whales will join the hunt to successfully kill the larger whale, taking turns trying to harass and drown the blue whale in groups of six to eight to attack when one group becomes exhausted[124] Predation by orcas on whale calves in high-productivity, high-latitude areas may account for great whale migrations during breeding season to low-productivity tropical waters where orcas are scarcer.[119][125]

Hunting a large whale usually takes several hours. Killer whales generally attack young or weak animals.[119] When hunting a young whale, a group chases it and its mother to exhaustion. Eventually, they separate the pair and surround the calf, drowning it by keeping it from surfacing, and may consume only its jaw and tongue.[119] Pods of female sperm whales sometimes protect themselves by forming a protective circle around their calves with their flukes facing outwards, using them to repel the attackers.[126] Rarely, large killer whale pods can overwhelm even adult female sperm whales. Adult bull sperm whales, which are large, powerful and aggressive when threatened, and fully grown adult blue whales, which are possibly too large to overwhelm, are not believed to be prey for killer whales.[127]

Prior to the advent of industrial whaling, great whales may have been the major food source for killer whales. The introduction of modern whaling techniques may have aided killer whales by the sound of exploding harpoons indicating the availability of prey to scavenge, and compressed air inflation of whale carcasses causing them to float, thus exposing them to scavenging. However, the devastation of great whale populations by unfettered whaling has possibly reduced their availability for killer whales, and caused them to expand their consumption of smaller marine mammals, thus contributing to the decline of these as well.[125]

Killer whale "spyhopping" before an attack on a Weddell seal

Other marine mammal prey species include nearly 20 species of seal, sea lion and fur seal. Walruses and sea otters are less frequently taken. Often, to avoid injury, killer whales disable their prey before killing and eating it. This may involve throwing it in the air, slapping it with their tails, ramming it, or breaching and landing on it.[128] In the Aleutian Islands, a decline in sea otter populations in the 1990s was controversially attributed by some scientists to killer whale predation, although with no direct evidence.[129] The decline of sea otters followed a decline in harbour seal and Steller sea lion populations, the killer whale's preferred prey,[a][131] which in turn may be substitutes for their original prey, now decimated by industrial whaling.[132][133][134]

In steeply banked beaches off Península Valdés, Argentina, and the Crozet Islands, killer whales feed on South American sea lions and southern elephant seals in shallow water, even beaching temporarily to grab prey before wriggling back to the sea. Beaching, usually fatal to cetaceans, is not an instinctive behaviour, and can require years of practice for the young.[135] Killer whales can then release the animal near juvenile whales, allowing the younger whales to practice the difficult capture technique on the now-weakened prey.[128][136] "Wave-hunting" killer whales "spy-hop" to locate Weddell seals, crabeater seals, leopard seals, and penguins resting on ice floes, and then swim in groups to create waves that wash over the floe. This washes the prey into the water, where other killer whales lie in wait.[52][137][138]

Killer whales have also been observed preying on terrestrial mammals, such as deer swimming between islands off the northwest coast of North America.[130] Killer whale cannibalism has also been reported based on analysis of stomach contents, but this is likely to be the result of scavenging remains dumped by whalers.[139] One killer whale was also attacked by its companions after being shot.[37] Although resident killer whales have never been observed to eat other marine mammals, they occasionally harass and kill porpoises and seals for no apparent reason.[140]

Killer whales in many areas may prey on cormorants and gulls.[141] A captive killer whale at Marineland of Canada discovered it could regurgitate fish onto the surface, attracting sea gulls, and then eat the birds. Four others then learned to copy the behaviour.[142]

Behaviour

Association of killer whales and black-browed albatrosses

Day-to-day killer whale behaviour generally consists of foraging, travelling, resting and socializing. Killer whales frequently engage in surface behaviour such as breaching (jumping completely out of the water) and tail-slapping. These activities may have a variety of purposes, such as courtship, communication, dislodging parasites, or play. Spyhopping is a behaviour in which a whale holds its head above water to view its surroundings.[143] Resident killer whales swim alongside porpoises and other dolphins.[144]

Social structure

A pair of killer whales in a transient population in Northwest Pacific

Killer whales are notable for their complex societies. Only elephants and higher primates live in comparably complex social structures.[145] Due to orcas' complex social bonds, many marine experts have concerns about how humane it is to keep them in captivity.[146]

Resident killer whales in the eastern North Pacific live in particularly complex and stable social groups. Unlike any other known mammal social structure, resident whales live with their mothers for their entire lives. These family groups are based on matrilines consisting of the eldest female (matriarch) and her sons and daughters, and the descendants of her daughters, etc. The average size of a matriline is 5.5 animals.[147] Because females can reach age 90, as many as four generations travel together. These matrilineal groups are highly stable. Individuals separate for only a few hours at a time, to mate or forage. With one exception, a killer whale named Luna, no permanent separation of an individual from a resident matriline has been recorded.[147]

Killer whales, like this one near Alaska, commonly breach, often lifting their entire bodies out of the water.

Closely related matrilines form loose aggregations called pods, usually consisting of one to four matrilines. Unlike matrilines, pods may separate for weeks or months at a time.[147] DNA testing indicates resident males nearly always mate with females from other pods.[148] Clans, the next level of resident social structure, are composed of pods with similar dialects, and common but older maternal heritage. Clan ranges overlap, mingling pods from different clans.[147] The final association layer, perhaps more arbitrarily defined than the familial groupings, is called the community, and is defined as a set of clans that regularly commingle. Clans within a community do not share vocal patterns.[b]

Transient pods are smaller than resident pods, typically consisting of an adult female and one or two of her offspring. Males typically maintain stronger relationships with their mothers than other females. These bonds can extend well into adulthood. Unlike residents, extended or permanent separation of transient offspring from natal matrilines is common, with juveniles and adults of both sexes participating. Some males become "rovers" and do not form long-term associations, occasionally joining groups that contain reproductive females.[149] As in resident clans, transient community members share an acoustic repertoire, although regional differences in vocalizations have been noted.[150]

Vocalizations

Multimedia relating to the orca
See also: Whale sound

Like all cetaceans, killer whales depend heavily on underwater sound for orientation, feeding, and communication. They produce three categories of sounds: clicks, whistles, and pulsed calls. Clicks are believed to be used primarily for navigation and discriminating prey and other objects in the surrounding environment, but are also commonly heard during social interactions.[33]

Northeast Pacific resident groups tend to be much more vocal than transient groups in the same waters.[151] Residents feed primarily on Chinook and chum, which are insensitive to killer whale calls (inferred from the audiogram of Atlantic salmon). In contrast, the marine mammal prey of transients hear whale calls well. Transients are typically silent.[151] They sometimes use a single click (called a cryptic click) rather than the long train of clicks observed in other populations. Residents are silent only when resting.

All members of a resident pod use similar calls, known collectively as a dialect. Dialects are composed of specific numbers and types of discrete, repetitive calls. They are complex and stable over time.[152] Call patterns and structure are distinctive within matrilines.[153] Newborns produce calls similar to their mothers, but have a more limited repertoire.[150] Individuals likely learn their dialect through contact with pod members.[154] Family-specific calls have been observed more frequently in the days following a calf's birth, which may help the calf learn them.[155] Dialects are probably an important means of maintaining group identity and cohesiveness. Similarity in dialects likely reflects the degree of relatedness between pods, with variation growing over time.[156] When pods meet, dominant call types decrease and subset call types increase. The use of both call types is called biphonation. The increased subset call types may be the distinguishing factor between pods and inter-pod relations.[153]

Dialects also distinguish types. Resident dialects contain seven to 17 (mean = 11) distinctive call types. All members of the North American west coast transient community express the same basic dialect, although minor regional variation in call types is evident. Preliminary research indicates offshore killer whales have group-specific dialects unlike those of residents and transients.[156]

Norwegian and Icelandic herring-eating orcas appear to have different vocalizations for activities like hunting.[157] A population that live in McMurdo Sound, Antarctica have 28 complex burst-pulse and whistle calls.[158]

Intelligence

Main article: Cetacean intelligence

Killer whales have the second-heaviest brains among marine mammals[159] (after sperm whales, which have the largest brain of any animal).[160] They can be trained in captivity and are often described as intelligent,[161][162] although defining and measuring "intelligence" is difficult in a species whose environment and behavioural strategies are very different from those of humans.[162]

A killer whale plays with a ball of ice, soon after a researcher threw a snowball at the whale.

Killer whales imitate others, and seem to deliberately teach skills to their kin. Off the Crozet Islands, mothers push their calves onto the beach, waiting to pull the youngster back if needed.[128][136]

People who have interacted closely with killer whales offer numerous anecdotes demonstrating the whales' curiosity, playfulness, and ability to solve problems. Alaskan killer whales have not only learned how to steal fish from longlines, but have also overcome a variety of techniques designed to stop them, such as the use of unbaited lines as decoys.[163] Once, fishermen placed their boats several miles apart, taking turns retrieving small amounts of their catch, in the hope that the whales would not have enough time to move between boats to steal the catch as it was being retrieved. A researcher described what happened next:

It worked really well for a while. Then the whales split into two groups. It didn't even take them an hour to figure it out. They were so thrilled when they figured out what was going on, that we were playing games. They were breaching by the boats.

— Craig Matkin[163]

In other anecdotes, researchers describe incidents in which wild killer whales playfully tease humans by repeatedly moving objects the humans are trying to reach,[164] or suddenly start to toss around a chunk of ice after a human throws a snowball.[165]

The killer whale's use of dialects and the passing of other learned behaviours from generation to generation have been described as a form of animal culture.[166]

The complex and stable vocal and behavioural cultures of sympatric groups of killer whales (Orcinus orca) appear to have no parallel outside humans and represent an independent evolution of cultural faculties.[167]

(Two species or populations are considered sympatric when they live in the same geographic area and thus regularly encounter one another.)

Life cycle

Mother orca with calf near South Georgia

Female killer whales begin to mature at around the age of 10 and reach peak fertility around 20,[168] experiencing periods of polyestrous cycling separated by non-cycling periods of three to 16 months. Females can often breed until age 40, followed by a rapid decrease in fertility.[168] Orcas are among the few animals that undergo menopause and live for decades after they have finished breeding.[169][170] The lifespans of wild females average 50 to 80 years.[171] Some are claimed to have lived substantially longer: Granny (J2) was estimated by some researchers to have been as old as 105 years at the time of her death, though a biopsy sample indicated her age as 65 to 80 years.[172][173][174] It is thought that orcas held in captivity tend to have shorter lives than those in the wild, although this is subject to scientific debate.[171][175][176]

Males mate with females from other pods, which prevents inbreeding. Gestation varies from 15 to 18 months. [177] Mothers usually calve a single offspring about once every five years. In resident pods, births occur at any time of year, although winter is the most common. Mortality is extremely high during the first seven months of life, when 37–50% of all calves die.[178] Weaning begins at about 12 months of age, and is complete by two years. According to observations in several regions, all male and female pod members participate in the care of the young.[145]

Males sexually mature at the age of 15, but do not typically reproduce until age 21. Wild males live around 29 years on average, with a maximum of about 60 years.[172] One male, known as Old Tom, was reportedly spotted every winter between the 1840s and 1930 off New South Wales, Australia, which would have made him up to 90 years old. Examination of his teeth indicated he died around age 35,[179] but this method of age determination is now believed to be inaccurate for older animals.[180] One male known to researchers in the Pacific Northwest (identified as J1) was estimated to have been 59 years old when he died in 2010.[181] Killer whales are unique among cetaceans, as their caudal sections elongate with age, making their heads relatively shorter.[63]

Infanticide, once thought to occur only in captive killer whales, was observed in wild populations by researchers off British Columbia on December 2, 2016. In this incident, an adult male killed the calf of a female within the same pod, with the adult male's mother also joining in the assault. It is theorized that the male killed the young calf in order to mate with its mother (something that occurs in other carnivore species), while the male's mother supported the breeding opportunity for her son. The attack ended when the calf's mother struck and injured the attacking male. Such behaviour matches that of many smaller dolphin species, such as the bottlenose dolphin.[182]

Conservation

The type C killer whale has two-toned grey colouring, including a dark "dorsal cape", in body areas where most killer whales have solid black colouring. Research is ongoing into whether one or more killer whale types are distinct species in need of protection.

In 2008, the IUCN (International Union for Conservation of Nature) changed its assessment of the killer whale's conservation status from conservation dependent to data deficient, recognizing that one or more killer whale types may actually be separate, endangered species.[3] Depletion of prey species, pollution, large-scale oil spills, and habitat disturbance caused by noise and conflicts with boats are the most significant worldwide threats.[3] In January 2020, the first killer whale in England and Wales since 2001 was found dead with a large fragment of plastic in its stomach.[183]

Like other animals at the highest trophic levels, the killer whale is particularly at risk of poisoning from bioaccumulation of toxins, including Polychlorinated biphenyls (PCBs).[184] European harbour seals have problems in reproductive and immune functions associated with high levels of PCBs and related contaminants, and a survey off the Washington coast found PCB levels in killer whales were higher than levels that had caused health problems in harbour seals.[184] Blubber samples in the Norwegian Arctic show higher levels of PCBs, pesticides and brominated flame-retardants than in polar bears. When food is scarce, killer whales metabolize blubber for energy, which increases pollutant concentrations in their blood.

In the Pacific Northwest, wild salmon stocks, a main resident food source, have declined dramatically in recent years.[3] In the Puget Sound region only 75 whales remain with few births over the last few years.[185] On the west coast of Alaska and the Aleutian Islands, seal and sea lion populations have also substantially declined.[186]

An adult female and her calf

In 2005, the United States government listed the southern resident community as an endangered population under the Endangered Species Act.[33] This community comprises three pods which live mostly in the Georgia and Haro Straits and Puget Sound in British Columbia and Washington. They do not breed outside of their community, which was once estimated at around 200 animals and later shrank to around 90.[187] In October 2008, the annual survey revealed seven were missing and presumed dead, reducing the count to 83.[188] This is potentially the largest decline in the population in the past 10 years. These deaths can be attributed to declines in Chinook salmon.[188]

Scientist Ken Balcomb has extensively studied killer whales since 1976; he is the research biologist responsible for discovering U.S. Navy sonar may harm killer whales. He studied killer whales from the Center for Whale Research, located in Friday Harbor, Washington.[189] He was also able to study killer whales from "his home porch perched above Puget Sound, where the animals hunt and play in summer months".[189] In May 2003, Balcomb (along with other whale watchers near the Puget Sound coastline) noticed uncharacteristic behaviour displayed by the killer whales. The whales seemed "agitated and were moving haphazardly, attempting to lift their heads free of the water" to escape the sound of the sonars.[189] "Balcomb confirmed at the time that strange underwater pinging noises detected with underwater microphones were sonar. The sound originated from a U.S. Navy frigate 12 miles (19 kilometres) distant, Balcomb said."[189] The impact of sonar waves on killer whales is potentially life-threatening. Three years prior to Balcomb's discovery, research in the Bahamas showed 14 beaked whales washed up on the shore. These whales were beached on the day U.S. Navy destroyers were activated into sonar exercise.[189] Of the 14 whales beached, six of them died. These six dead whales were studied, and CAT scans of two of the whale heads showed hemorrhaging around the brain and the ears, which is consistent with decompression sickness.[189]

Another conservation concern was made public in September 2008 when the Canadian government decided it was not necessary to enforce further protections (including the Species at Risk Act in place to protect endangered animals along with their habitats) for killer whales aside from the laws already in place. In response to this decision, six environmental groups sued the federal government, claiming killer whales were facing many threats on the British Columbia Coast and the federal government did nothing to protect them from these threats.[190] A legal and scientific nonprofit organization, Ecojustice, led the lawsuit and represented the David Suzuki Foundation, Environmental Defence, Greenpeace Canada, International Fund for Animal Welfare, the Raincoast Conservation Foundation, and the Wilderness Committee.[190] Many scientists involved in this lawsuit, including Bill Wareham, a marine scientist with the David Suzuki Foundation, noted increased boat traffic, water toxic wastes, and low salmon population as major threats, putting approximately 87 killer whales[190] on the British Columbia Coast in danger.

The last known AT1 pod offspring, AT3, swimming in Resurrection Bay

Underwater noise from shipping, drilling, and other human activities is a significant concern in some key killer whale habitats, including Johnstone Strait and Haro Strait.[191] In the mid-1990s, loud underwater noises from salmon farms were used to deter seals. Killer whales also avoided the surrounding waters.[192] High-intensity sonar used by the Navy disturbs killer whales along with other marine mammals.[193] Killer whales are popular with whale watchers, which may stress the whales and alter their behaviour, particularly if boats approach too closely or block their lines of travel.[194]

The Exxon Valdez oil spill adversely affected killer whales in Prince William Sound and Alaska's Kenai Fjords region. Eleven members (about half) of one resident pod disappeared in the following year. The spill damaged salmon and other prey populations, which in turn damaged local killer whales. By 2009, scientists estimated the AT1 transient population (considered part of a larger population of 346 transients), numbered only seven individuals and had not reproduced since the spill. This population is expected to die out.[195][196]

A 2018 study published in Science found that global killer whale populations are poised to dramatically decline due to exposure to toxic chemical and PCB pollution.[197]

Relationship with humans

Indigenous cultures

See also: Animal worship
Haida sculpture by Bill Reid

The indigenous peoples of the Pacific Northwest Coast feature killer whales throughout their art, history, spirituality and religion. The Haida regarded killer whales as the most powerful animals in the ocean, and their mythology tells of killer whales living in houses and towns under the sea. According to these myths, they took on human form when submerged, and humans who drowned went to live with them.[7] For the Kwakwaka'wakw, the killer whale was regarded as the ruler of the undersea world, with sea lions for slaves and dolphins for warriors.[7] In Nuu-chah-nulth and Kwakwaka'wakw mythology, killer whales may embody the souls of deceased chiefs.[7] The Tlingit of southeastern Alaska regarded the killer whale as custodian of the sea and a benefactor of humans.[198]

The Maritime Archaic people of Newfoundland also had great respect for killer whales, as evidenced by stone carvings found in a 4,000-year-old burial at the Port au Choix Archaeological Site.[199][200]

In the tales and beliefs of the Siberian Yupik people, killer whales are said to appear as wolves in winter, and wolves as killer whales in summer.[201][202][203][204] Killer whales are believed to assist their hunters in driving walrus.[205] Reverence is expressed in several forms: the boat represents the animal, and a wooden carving hung from the hunter's belt.[203] Small sacrifices such as tobacco or meat are strewn into the sea for them.[205][204]

Indigenous Ainu tribe often referred to killer whales in their folklore and myth as Repun Kamuy (God of Sea/Offshore) to bring fortunes (whales) to the coasts, and there had been traditional funerals for stranded or deceased orcas akin to funerals for other animals such as brown bears.[206]

"Killer" stereotype

Main article: Killer whale attacks on humans

In Western cultures, killer whales were historically feared as dangerous, savage predators.[8] The first written description of a killer whale was given by Pliny the Elder circa AD 70, who wrote, "Orcas (the appearance of which no image can express, other than an enormous mass of savage flesh with teeth) are the enemy of [other kinds of whale]... they charge and pierce them like warships ramming."[207]

Male killer whale depicted in St Mary's in Greifswald, Germany, 1545[10]

Of the very few confirmed attacks on humans by wild killer whales, none have been fatal.[208] In one instance, killer whales tried to tip ice floes on which a dog team and photographer of the Terra Nova Expedition were standing.[209] The sled dogs' barking is speculated to have sounded enough like seal calls to trigger the killer whale's hunting curiosity. In the 1970s, a surfer in California was bitten, and in 2005, a boy in Alaska who was splashing in a region frequented by harbour seals was bumped by a killer whale that apparently misidentified him as prey.[210] Unlike wild killer whales, captive killer whales have made nearly two dozen attacks on humans since the 1970s, some of which have been fatal.[211][212]

Competition with fishermen also led to killer whales being regarded as pests. In the waters of the Pacific Northwest and Iceland, the shooting of killer whales was accepted and even encouraged by governments.[8] As an indication of the intensity of shooting that occurred until fairly recently, about 25% of the killer whales captured in Puget Sound for aquariums through 1970 bore bullet scars.[213] The U.S. Navy claimed to have deliberately killed hundreds of killer whales in Icelandic waters in 1956 with machine guns, rockets, and depth charges.[214][215]

From July to October 2020 there were at least forty reliable reports of orcas attacking boats off the Atlantic coast of Portugal and Spain, unusual and unprecedented behaviour. The nudging, biting and ramming attacks, on medium-size sailing boats sailing at moderate speed, concentrated on the rudder, with some impacts on the hull. A small group of orcas are believed to be responsible, with three juveniles which have been named black Gladis, white Gladis and grey Gladis, identified as present in most attacks. While the incidents were terrifying, no people were injured. The Portuguese coastguard banned small sailing vessels from a region where several incidents had been reported. It is thought that the behaviour is playful, rather than aggressive or vengeful.[216]

Modern Western attitudes

See also: Killer whales in popular culture
Play media
Ingrid Visser's research team filming orcas in New Zealand

Western attitudes towards killer whales have changed dramatically in recent decades. In the mid-1960s and early 1970s, killer whales came to much greater public and scientific awareness, starting with the first live-capture and display of a killer whale known as Moby Doll, a resident harpooned off Saturna Island in 1964.[8] So little was known at the time, it was nearly two months before the whale's keepers discovered what food (fish) it was willing to eat. To the surprise of those who saw him, Moby Doll was a docile, non-aggressive whale who made no attempts to attack humans.[217]

In 2002, the orphan Springer was successfully returned to her family.

Between 1964 and 1976, 50 killer whales from the Pacific Northwest were captured for display in aquaria, and public interest in the animals grew. In the 1970s, research pioneered by Michael Bigg led to the discovery of the species' complex social structure, its use of vocal communication, and its extraordinarily stable mother–offspring bonds. Through photo-identification techniques, individuals were named and tracked over decades.[218]

Bigg's techniques also revealed the Pacific Northwest population was in the low hundreds rather than the thousands that had been previously assumed.[8] The southern resident community alone had lost 48 of its members to captivity; by 1976, only 80 remained.[219] In the Pacific Northwest, the species that had unthinkingly been targeted became a cultural icon within a few decades.[187]

The public's growing appreciation also led to growing opposition to whale–keeping in aquarium. Only one whale has been taken in North American waters since 1976. In recent years, the extent of the public's interest in killer whales has manifested itself in several high-profile efforts surrounding individuals. Following the success of the 1993 film Free Willy, the movie's captive star Keiko was returned to the coast of his native Iceland in 2002. The director of the International Marine Mammal Project for the Earth Island Institute, David Phillips, led the efforts to return Keiko to the Iceland waters.[220] Keiko however did not adapt to the harsh climate of the Arctic Ocean, and died a year into his release after contracting pneumonia, at the age of 27.[221] In 2002, the orphan Springer was discovered in Puget Sound, Washington. She became the first whale to be successfully reintegrated into a wild pod after human intervention, crystallizing decades of research into the vocal behaviour and social structure of the region's killer whales.[222] The saving of Springer raised hopes that another young killer whale named Luna, which had become separated from his pod, could be returned to it. However, his case was marked by controversy about whether and how to intervene, and in 2006, Luna was killed by a boat propeller.[223]

Whaling

Main article: Whaling
The killer whale named Old Tom swims alongside a whaleboat, flanking a whale calf. The boat is being towed by a harpooned whale (not visible here), near Eden, Australia.

The earlier of known records of commercial hunting of killer whales date to the 18th century in Japan. During the 19th and early 20th centuries, the global whaling industry caught immense numbers of baleen and sperm whales, but largely ignored killer whales because of their limited amounts of recoverable oil, their smaller populations, and the difficulty of taking them.[148] Once the stocks of larger species were depleted, killer whales were targeted by commercial whalers in the mid-20th century. Between 1954 and 1997, Japan took 1,178 killer whales (although the Ministry of the Environment claims that there had been domestic catches of about 1,600 whales between late 1940s to 1960s[224]) and Norway took 987.[225] Extensive hunting of killer whales, including an Antarctic catch of 916 in 1979–80 alone, prompted the International Whaling Commission to recommend a ban on commercial hunting of the species pending further research.[225] Today, no country carries out a substantial hunt, although Indonesia and Greenland permit small subsistence hunts (see Aboriginal whaling). Other than commercial hunts, killer whales were hunted along Japanese coasts out of public concern for potential conflicts with fisheries. Such cases include a semi-resident male-female pair in Akashi Strait and Harimanada being killed in the Seto Inland Sea in 1957,[226][227] the killing of five whales from a pod of 11 members that swam into Tokyo Bay in 1970,[228] and a catch record in southern Taiwan in the 1990s.[82][229]

Cooperation with humans

Killer whales have helped humans hunting other whales.[230] One well-known example was the killer whales of Eden, Australia, including the male known as Old Tom. Whalers more often considered them a nuisance, however, as orcas would gather to scavenge meat from the whalers' catch.[230] Some populations, such as in Alaska's Prince William Sound, may have been reduced significantly by whalers shooting them in retaliation.[19]

Whale watching

Whale watching continues to increase in popularity, but may have some problematic impacts on killer whales. Exposure to exhaust gasses from large amounts of vessel traffic is causing concern for the overall health of the 75 remaining southern resident killer whales (SRKWs) left as of early 2019.[231] This population is followed by approximately 20 vessels for 12 hours a day during the months May–September.[232] Researchers discovered that these vessels are in the line of sight for these whales for 98–99.5% of daylight hours.[232] With so many vessels, the air quality around these whales deteriorates and impacts their health. Air pollutants that bind with exhaust fumes are responsible for the activation of the cytochrome P450 1A gene family.[232] Researchers have successfully identified this gene in skin biopsies of live whales and also the lungs of deceased whales. A direct correlation between activation of this gene and the air pollutants can not be made because there are other known factors that will induce the same gene. Vessels can have either wet or dry exhaust systems, with wet exhaust systems leaving more pollutants in the water due to various gas solubility. A modelling study determined that the lowest-observed-adverse-effect-level (LOAEL) of exhaust pollutants was about 12% of the human dose.[232]

As a response to this, in 2017 boats off the British Columbia coast now have a minimum approach distance of 200 metres compared to the previous 100 metres. This new rule complements Washington State's minimum approach zone of 180 metres that has been in effect since 2011. If a whale approaches a vessel it must be placed in neutral until the whale passes. The World Health Organization has set air quality standards in an effort to control the emissions produced by these vessels.[233]

Captivity

Main article: Captive killer whales
Lolita, at the Miami Seaquarium, is one of the oldest whales in captivity.

The killer whale's intelligence, trainability, striking appearance, playfulness in captivity and sheer size have made it a popular exhibit at aquaria and aquatic theme parks. From 1976 to 1997, 55 whales were taken from the wild in Iceland, 19 from Japan, and three from Argentina. These figures exclude animals that died during capture. Live captures fell dramatically in the 1990s, and by 1999, about 40% of the 48 animals on display in the world were captive-born.[234]

Organizations such as World Animal Protection and the Whale and Dolphin Conservation campaign against the practice of keeping them in captivity. In captivity, they often develop pathologies, such as the dorsal fin collapse seen in 60–90% of captive males. Captives have vastly reduced life expectancies, on average only living into their 20s.[c] That said, a 2015 study coauthored by staff at SeaWorld and the Minnesota Zoo suggested no significant difference in survivorship between free-ranging and captive killer whales.[175] However, in the wild, females who survive infancy live 46 years on average, and up to 70–80 years in rare cases. Wild males who survive infancy live 31 years on average, and up to 50–60 years.[235] Captivity usually bears little resemblance to wild habitat, and captive whales' social groups are foreign to those found in the wild. Critics claim captive life is stressful due to these factors and the requirement to perform circus tricks that are not part of wild killer whale behaviour, see above.[236] Wild killer whales may travel up to 160 kilometres (100 mi) in a day, and critics say the animals are too big and intelligent to be suitable for captivity.[161] Captives occasionally act aggressively towards themselves, their tankmates, or humans, which critics say is a result of stress.[211] Between 1991 and 2010, the bull orca known as Tilikum was involved in the death of three people, and was featured in the critically acclaimed 2013 film Blackfish.[237] Tilikum lived at SeaWorld from 1992 until his death in 2017.[238][239][240][241][242]

In March 2016, SeaWorld announced that they would be ending their orca breeding program and their theatrical shows.[243] As of 2020, theatrical shows featuring orcas are still ongoing.[244]

See also

  • List of marine mammal species
    • List of cetaceans
      • Livyatan melvillei – occupied a similar ecological niche
  • List of whale vocalizations
  • Ingrid Visser (researcher) – a New Zealand biologist who swims with wild killer whales
  • Marine biology
  • Sinonyx

Footnotes

  1. ^ According to Baird,[130] killer whales prefer harbour seals to sea lions and porpoises in some areas.
  2. ^ In the northeast Pacific, three communities of fish-eating killer whales have been identified: the southern community (one clan, three pods, 90 killer whales as of 2006), the northern community (three clans, 16 pods, 214 killer whales as of 2000), and the south Alaskan community (two clans, 11 pods, 211 killer whales as of 2000).
  3. ^ Although there are examples of killer whales living longer, including several over 30 years old, and two captive orcas (Corky II and Lolita) are in their mid-40s.

References

  1. ^ Mead, J.G.; Brownell, R. L. Jr. (2005). "Order Cetacea". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 723–743. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. ^ "Orcinus orca Linnaeus 1758". Fossilworks. Archived from the original on April 27, 2020. Retrieved April 28, 2018.
  3. ^ a b c d e f Reeves, R.; Pitman, R.L.; Ford, J.K.B. (2017). "Orcinus orca". IUCN Red List of Threatened Species. 2017: e.T15421A50368125. Retrieved February 15, 2020.
  4. ^ "Orcinus orca (Linnaeus, 1758)". Integrated Taxonomic Information System. Retrieved March 9, 2011.
  5. ^ "Orcinus Fitzinger, 1860". Integrated Taxonomic Information System. Retrieved March 9, 2011.
  6. ^ Ford, Ellis & Balcomb 2000, p. 12.
  7. ^ a b c d Francis & Hewlett 2007, pp. 115–120.
  8. ^ a b c d e Obee & Ellis 1992, pp. Chapter 1.
  9. ^ Linnaeus, C. (1758). Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I (in Latin). v.1 (10th ed.). Holmiae. (Laurentii Salvii). p. 824. Archived from the original on March 25, 2017. Retrieved January 14, 2018.
  10. ^ a b Zum Wal in der Marienkirche (in German). St. Mary's Church, Greifswald. Retrieved February 16, 2010
  11. ^ Carwardine 2001, p. 19.
  12. ^ LeDuc, R. G.; Perrin, W. F.; Dizon, A.E. (1999). "Phylogenetic relationships among the delphinid cetaceans based on full cytochrome b sequences". Marine Mammal Science. 15 (3): 619–648. doi:10.1111/j.1748-7692.1999.tb00833.x.
  13. ^ Horreo, Jose L. (2018). "New insights into the phylogenetic relationships among the oceanic dolphins (Cetacea: Delphinidae)". Journal of Zoological Systematics and Evolutionary Research. 57 (2): 476–480. doi:10.1111/jzs.12255.
  14. ^ a b Mary Price (July 22, 2013). "Orcas: How Science Debunked Superstition". National Wildlife Federation. Archived from the original on January 31, 2017. Retrieved July 30, 2020.
  15. ^ Ford, Ellis & Balcomb 2000, p. 69.
  16. ^ Killer Whales. Scientific Classification Archived August 15, 2012, at the Wayback Machine, Seaworld.org, September 23, 2010, Retrieved September 9, 2010.
  17. ^ Best, P.B. 2007 Whales and Dolphins of the Southern African Subregion ISBN 978-0-521-89710-5
  18. ^ Leatherwood, Stephen and Larry J. Hobbs (1988). Whales, dolphins, and porpoises of the eastern North Pacific and adjacent Arctic waters: a guide to their identification, p. 118. Courier Dover Publications. ISBN 0-486-25651-0 Retrieved January 28, 2010.
  19. ^ a b (Baird 2002). Status of Killer Whales in Canada Archived November 8, 2011, at the Wayback Machine. Contract report to the Committee on the Status of Endangered Wildlife in Canada, Ottawa, ON, Canada. Also published as Status of Killer Whales, Orcinus orca, in Canada Archived July 14, 2010, at the Wayback Machine The Canadian Field-Naturalist 115 (4) (2001), 676–701. Retrieved January 26, 2010.
  20. ^ a b c d e f Pitman, Robert L.; Ensor, Paul (2003). "Three forms of killer whales (Orcinus orca) in Antarctic waters" (PDF). Journal of Cetacean Research and Management. 5 (2): 131–139. Archived (PDF) from the original on April 27, 2020. Retrieved January 9, 2010.
  21. ^ De Bruyn, P. J. N.; Tosh, C. A.; Terauds, A. (2013). "Killer whale ecotypes: Is there a global model?". Biological Reviews. 88 (1): 62–80. doi:10.1111/j.1469-185X.2012.00239.x. hdl:2263/21531. PMID 22882545. S2CID 6336624.
  22. ^ a b Ford, J.K.B.; Ellis, G.M.; Barrett-Lennard, L.G.; Morton, A.B.; Palm, R.S.; Balcomb, K.C. (1998). "Dietary specialization in two sympatric populations of killer whales (Orcinus orca) in coastal British Columbia and adjacent waters". Canadian Journal of Zoology. 76 (8): 1456–1471. doi:10.1139/z98-089.
  23. ^ Berta, Annalisa; Sumich, James L.; Kovacs, Kit M. (2006). Marine mammals: evolutionary biology. Academic Press. p. 387. ISBN 978-0-12-088552-7.
  24. ^ a b c d e Carwardine 2001, pp. 40–47.
  25. ^ Ford, Ellis & Balcomb 2000, p. 23.
  26. ^ Ford J.K.B. and, G.M. Ellis. 1999. Transients: Mammal-hunting killer whales of British Columbia, Washington, and Southeastern Alaska. UBC Press, Vancouver.
  27. ^ Deecke, V.B.; Ford, J.K.B.; Slater, P.J.B. (2005). "The vocal behaviour of mammal-eating killer whales: Communicating with costly calls". Animal Behaviour. 69 (2): 395–405. doi:10.1016/j.anbehav.2004.04.014. S2CID 16899659. Archived from the original on September 15, 2020. Retrieved February 4, 2020.
  28. ^ NMFS 2005, p. 24.
  29. ^ Bellaart, Darrell (December 4, 2012). "Transient label is pushed aside to honour renowned whale researcher". Nanaimo Daily News. Archived from the original on March 1, 2014. Retrieved December 4, 2012.
  30. ^ Ford, Ellis & Balcomb 2000, p. 21.
  31. ^ a b c Pyle, Peter; Schramm, Mary Jane; Keiper, Carol; Anderson, Scot D. (1999). "Predation on a white shark (Carcharodon carcharias) by a killer whale (Orcinus orca) and a possible case of competitive displacement" (PDF). Marine Mammal Science. 15 (2): 563–568. doi:10.1111/j.1748-7692.1999.tb00822.x. Archived from the original (PDF) on March 22, 2012. Retrieved April 28, 2014.
  32. ^ Dahlheim, M.E.; Schulman-Janiger, A.; Black, N.; Ternullo, R.; Balcomb, K.C. (2008). "Eastern temperate North Pacific offshore killer whales (Orcinus orca): Occurrence, movements, and insights into feeding ecology". Marine Mammal Science. 24 (3): 719–729. doi:10.1111/j.1748-7692.2008.00206.x. Archived from the original on October 13, 2010. Retrieved February 5, 2019.
  33. ^ a b c d "Killer whale (Orcinus orca)". NOAA Fisheries. Office of Protected Resources, National Marine Fisheries Service. Archived from the original on July 9, 2017. Retrieved August 15, 2017.
  34. ^ Baird, R.W.; Dill, L.M. (1995). "Occurrence and behaviour of transient killer whales: seasonal and pod-specific variability, foraging behaviour, and prey handling". Canadian Journal of Zoology. 73 (7): 1300–1311. doi:10.1139/z95-154.
  35. ^ Barrett-Lennard LG, Ellis GM. 2001. Population structure and genetic variability in northeastern Pacific killer whales: Towards an assessment of population viability. Canadian Science Advisory Secretariat, Ottawa, Canada.
  36. ^ NMFS 2005, p. 23.
  37. ^ a b c Jefferson, T. A.; Stacey, P. J.; Baird, R. W. (1991). "A review of killer whale interactions with other marine mammals: predation to co-existence" (PDF). Mammal Review. 21 (4): 151–180. doi:10.1111/j.1365-2907.1991.tb00291.x. Archived (PDF) from the original on July 22, 2011. Retrieved February 23, 2010.
  38. ^ Bourton, Jody. Two killer whale types found in UK waters Archived January 14, 2010, at the Wayback Machine, Earth News, BBC, January 5, 2010. Retrieved February 23, 2010.
  39. ^ a b Foote, Andrew D.; Newton, Jason; Piertney, Stuart B.; Willerslev, Eske; Gilbert, M. Thomas P. (2009). "Ecological, morphological and genetic divergence of sympatric North Atlantic killer whale populations" (PDF). Molecular Ecology. 18 (24): 5207–17. doi:10.1111/j.1365-294X.2009.04407.x. PMID 20050301. S2CID 331555. Archived (PDF) from the original on July 9, 2011. Retrieved February 27, 2010.
  40. ^ Waite, J.M.; Friday, N.A.; Moore, S.E. (2002). "Killer Whale (Orcinus orca) distribution and abundance in the central and southeastern Bering Sea, July 1999 and June 2000". Marine Mammal Science. 18 (3): 779–786. doi:10.1111/j.1748-7692.2002.tb01073.x. Archived from the original on September 15, 2020. Retrieved July 11, 2019.
  41. ^ Christensen, I. 1984. Growth and reproduction of killer whales, Orcinus orca, in Norwegian coastal waters. Reports of the International Whaling Commission Special Issue, 6: 253–258.
  42. ^ Ford, Ellis & Balcomb 2000, p. 27.
  43. ^ Evans, W. E.; Yablokov, A. V.; Bowles, A. E. (1982). "Geographic Variation in the Color Pattern of Killer Whales (Orcinus orca)" (PDF). Reports of the International Whaling Commission. 32: 687–694. Archived from the original (PDF) on July 13, 2011.
  44. ^ Gough, Myles (January 9, 2015). "First video footage of rare 'Type D' orcas". Science Alert. Archived from the original on January 14, 2015. Retrieved January 11, 2015.
  45. ^ Tennenhouse, Erica (March 1, 2018). "Mysterious orcas filmed underwater for first time". National Geographic. Archived from the original on March 31, 2019. Retrieved April 12, 2019.
  46. ^ "Sea Shepherd documents rare 'Type D' orcas". GrindTV. January 5, 2015. Archived from the original on January 11, 2015. Retrieved January 6, 2015.
  47. ^ a b Pitman, Robert L.; Durban, John W.; Greenfelder, Michael; Guinet, Christophe; Jorgensen, Morton; Olson, Paula A.; Plana, Jordi; Tixier, Paul; Towers, Jared R. (August 7, 2010). "Observations of a distinctive morphotype of killer whale (Orcinus orca), type D, from subantarctic waters". Polar Biology. 34 (2): 303–306. doi:10.1007/s00300-010-0871-3. S2CID 20734772. Archived from the original on September 15, 2020. Retrieved February 4, 2020.
  48. ^ Rejcek, Peter. "The Antarctic Sun: News about Antarctica – Killer News". Antarcticsun.usap.gov. Archived from the original on October 15, 2011. Retrieved February 16, 2011.
  49. ^ Gorter, Uko. Newsletter of the Puget Sound Chapter of the American Cetacean Society Archived November 6, 2006, at the Wayback Machine, Spring 2004. Retrieved February 16, 2010.
  50. ^ Pitman, Robert L.; Robertson, Kelly M.; Leduc, Richard G. (2008). "Mitochondrial sequence divergence among Antarctic killer whale ecotypes is consistent with multiple species". Biology Letters. 4 (4): 426–9. doi:10.1098/rsbl.2008.0168. PMC 2610147. PMID 18524738.
  51. ^ Morin, Phillip A; Archer, Frederick; Foote, Andrew D; Vilstrup, Julia; Allen, Eric E; Wade, Paul; Durban, John; Parsons, Kim; Pitman, Robert (2010). "Complete mitochondrial genome phylogeographic analysis of killer whales (Orcinus orca) indicates multiple species". Genome Research. 20 (7): 908–916. doi:10.1101/gr.102954.109. PMC 2892092. PMID 20413674.
  52. ^ a b c WADE, NICHOLAS (April 26, 2010). "Cracking Orca's Code: It Comes in Several Types". New York Times. Archived from the original on July 1, 2017. Retrieved February 17, 2017.
  53. ^ Schrope, Mark (2007). "Food chains: Killer in the kelp". Nature. 445 (7129): 703–705. Bibcode:2007Natur.445..703S. doi:10.1038/445703a. PMID 17301765. S2CID 4421362. Archived from the original on September 15, 2020. Retrieved February 4, 2020.
  54. ^ Poncelet, Eric. Killer whale biology: Morphology Archived October 25, 2016, at the Wayback Machine. Retrieved February 16, 2010
  55. ^ "Killer Whales: Physical Characteristics". Seaworld.org. Archived from the original on February 13, 2010. Retrieved December 30, 2009.
  56. ^ Carwardine 2001, p. 20.
  57. ^ "Wild Whales". Vancouver Aquarium. Archived from the original on April 5, 2012. Retrieved March 23, 2012.
  58. ^ Heptner et al. 1996, p. 683.
  59. ^ Baird 2002.
  60. ^ Olsen, K. (2006). National Wildlife 44 (6) (October/November), 22–30
  61. ^ Stewart, D. (2001). National Wildlife 39 (1) (December/January), 54–59
  62. ^ Heyning, J. E.; Dahlheim, M. E. (1988). "Orcinus orca" (PDF). Mammalian Species. 304 (304): 1–9. doi:10.2307/3504225. JSTOR 3504225. Archived from the original (PDF) on January 18, 2012.
  63. ^ a b c Heptner et al. 1996, p. 681.
  64. ^ Orca (Killer whale). American Cetacean Society. Retrieved January 2, 2009
  65. ^ Ford, Ellis & Balcomb 2000, p. 45.
  66. ^ Obee & Ellis 1992, pp. 1–27.
  67. ^ a b Rare White Killer Whale Spotted in Alaskan Waters From NOAA Ship Oscar Dyson Archived May 5, 2010, at the Wayback Machine, news release, National Oceanic and Atmospheric Administration, March 6, 2008. Retrieved March 20, 2010
  68. ^ a b Mary Pemberton. Rare white killer whale spotted in Alaska Archived July 7, 2017, at the Wayback Machine, NBC News, March 7, 2008
  69. ^ "Russian scientists seeking white whale -- really". Fox News. April 23, 2012. Archived from the original on April 25, 2012. Retrieved April 23, 2012.
  70. ^ "White killer whale adult spotted for first time in wild". BBC News. April 23, 2012. Archived from the original on December 22, 2019. Retrieved April 23, 2012.
  71. ^ Carwardine 2001, pp. 30–32.
  72. ^ a b "Killer Whales — Adaptations for an Aquatic Environment". Seaworld.org. Archived from the original on September 4, 2013. Retrieved September 14, 2013.
  73. ^ N. W. Kasting, S. A. L. Adderly, T. Safford, K. G. Hewlett (1989). "Thermoregulation in Beluga (Delphinapterus luecas) and Killer (Orcinus orca) Whales"
  74. ^ M. P. Spencer, T. A. Gornall, 3rd, and T. C. Poulter (1967). Respiratory and cardiac activity of killer whales Archived June 11, 2015, at the Wayback Machine.
  75. ^ a b c d e Forney, K.A.; Wade, P. (2007). "Worldwide distribution and abundance of killer whales" (PDF). In Estes, James A.; DeMaster, Douglas P.; Doak, Daniel F.; Williams, Terrie M.; Brownell, Robert L. Jr. (eds.). Whales, whaling and ocean ecosystems. Berkeley: University of California Press. pp. 145–162. ISBN 978-0-520-24884-7. Archived (PDF) from the original on August 7, 2020. Retrieved February 25, 2014.
  76. ^ Carwardine 2001, p. 21.
  77. ^ Baird 2002, p. 128.
  78. ^ Ling, J. K. (1991). "Recent sightings of killer whales, Orcinus orca (Cetacea: Delphinidae), in South Australia". Transactions of the Royal Society of South Australia. 115: 95–98. Archived from the original on February 21, 2020. Retrieved February 14, 2020.
  79. ^ Jack W. Lawson & Tara S. Stevens (2014). "Historic and current distribution patterns, and minimum abundance of killer whales (Orcinus orca) in the north-west Atlantic". Journal of the Marine Biological Association of the United Kingdom. 94 (6): 1253–1265. doi:10.1017/s0025315413001409. S2CID 84750726.
  80. ^ "A first ID match for the orcas of the Indian Ocean". Whale and Dolphin Conservation. November 11, 2015. Archived from the original on October 20, 2017. Retrieved October 19, 2017.
  81. ^ Notarbartolo di Sciara, G.; et al. (May 12–24, 2014). "Summary review of cetaceans of the Red Sea" (PDF). International Whaling Commission. Archived (PDF) from the original on October 19, 2017. Retrieved October 20, 2017.
  82. ^ a b Kaiya Z.; Leatherwood S.; Jefferson A.T. (1995). "Records of Small Cetaceans in Chinese Waters: A Review" (PDF). Asian Marine Biology. 12: 119–139. Archived (PDF) from the original on July 17, 2015. Retrieved December 24, 2014.
  83. ^ "Killer whales in Hawai'i". Cascadia Research.org. August 16, 2016. Archived from the original on October 20, 2017. Retrieved October 19, 2017.
  84. ^ a b Baird, R. W.; et al. (2006). "Killer whales in Hawaiian waters: information on population identity and feeding habits" (PDF). Pacific Science. 60 (4): 523–530. doi:10.1353/psc.2006.0024. hdl:10125/22585. S2CID 16788148. Archived (PDF) from the original on October 23, 2017. Retrieved October 23, 2017.
  85. ^ a b Weir, C. R.; Collins, T.; Carvalho, I.; Rosenbaum, H. C. (2010). "Killer whales (Orcinus orca) in Angolan and Gulf of Guinea waters, tropical West Africa" (PDF). Journal of the Marine Biological Association of the United Kingdom. 90 (8): 1601–1611. doi:10.1017/S002531541000072X. S2CID 84721171. Archived from the original (PDF) on September 30, 2014.
  86. ^ Visser N.I.. Killer whales in Papua New Guinea waters Archived April 26, 2014, at the Wayback Machine. Orca Research Trust
  87. ^ Reeves, R.R.; Notarbartolo di Sciara, G., eds. (2006). The Status and Distribution of Cetaceans in the Black Sea and Mediterranean Sea (PDF) (Report). Malaga, Spain: IUCN Centre for Mediterranean Cooperation. Archived from the original (PDF) on March 12, 2011.
  88. ^ Notarbartolo‐di‐Sciara, G. (1987). "Killer Whale, Orcinus orca, in the Mediterranean Sea". Marine Mammal Science. 3 (4): 356–360. doi:10.1111/j.1748-7692.1987.tb00324.x.
  89. ^ Merlen, Godfrey (1999). "The orca in Galapagos: 135 sightings". Noticias de Galapagos. 60: 2–8. Archived from the original on September 15, 2020. Retrieved March 14, 2019.
  90. ^ Kwan, Jennifer. Canada Finds Killer Whales Drawn to Warmer Arctic Archived August 17, 2017, at the Wayback Machine, Reuters, January 22, 2007.
  91. ^ a b Baird 2002, p. 10.
  92. ^ Southern Resident Killer Whale Research – October 2003 Archived March 6, 2014, at the Wayback Machine, Northwest Fisheries Science Center. Updated February 14, 2007. Retrieved January 26, 2010
  93. ^ NMFS 2005, pp. 24–29.
  94. ^ a b Ford & Ellis 2006.
  95. ^ NMFS 2005, p. 46.
  96. ^ Ecology of Japanese Coastal Orcas Archived August 22, 2009, at the Wayback Machine, sha-chi.jp. Retrieved February 17, 2010
  97. ^ Ten Years after Taiji Orca Capture Archived March 1, 2014, at the Wayback Machine, January 28, 2007. Iruka (dolphin) and Kujira (whale) Action Network (IKAN): Iruma, Saitama Prefecture, Japan. Retrieved February 17, 2010
  98. ^ "Orcinus orca – Orca (Killer Whale)". Marinebio.org. Archived from the original on September 16, 2011. Retrieved June 26, 2007.
  99. ^ NMFS 2005, p. 17.
  100. ^ Morell, Virginia (2011). "Killer Whales Earn Their Name". Science. 331 (6015): 274–276. Bibcode:2011Sci...331..274M. doi:10.1126/science.331.6015.274. PMID 21252323.
  101. ^ Miller, Patrick James O'Malley; Shapiro, Ari Daniel; Deecke, Volker Bernt (November 2010). "The diving behaviour of mammal-eating killer whales : variations with ecological not physiological factors" (PDF). Canadian Journal of Zoology. 88 (11): 1103–1112. doi:10.1139/Z10-080. Archived (PDF) from the original on July 20, 2018. Retrieved August 23, 2020. Overall, the whales spent 50% of their time 8 m or shallower and 90% of their time 40 m or shallower
  102. ^ Reisinger, Ryan R.; Keith, Mark; Andrews, Russel D.; de Bruyn, P.J.N. (December 2015). "Movement and diving of killer whales (Orcinus orca) at a Southern Ocean archipelago". Journal of Experimental Marine Biology and Ecology. 473: 90–102. doi:10.1016/j.jembe.2015.08.008. hdl:2263/49986. maximum dive depths were 767.5 and 499.5 m
  103. ^ Towers, Jared R; Tixier, Paul; Ross, Katherine A; Bennett, John; Arnould, John P Y; Pitman, Robert L; Durban, John W; Northridge, Simon (January 2019). "Movements and dive behaviour of a toothfish-depredating killer and sperm whale". ICES Journal of Marine Science. 76 (1): 298–311. doi:10.1093/icesjms/fsy118. S2CID 91256980. The killer whale dove >750 m on five occasions while depredating (maximum: 1087 m), but these deep dives were always followed by long periods (3.9–4.6 h) of shallow (<100 m) diving.
  104. ^ NMFS 2005, p. 18.
  105. ^ Hughes, Catherine D. "National Geographic creature feature". Archived from the original on May 11, 2010. Retrieved July 25, 2007.
  106. ^ Similä, T.; Ugarte, F. (1993). "Surface and underwater observations of cooperatively feeding killer whales in Northern Norway". Canadian Journal of Zoology. 71 (8): 1494–1499. doi:10.1139/z93-210.
  107. ^ a b Visser, Ingrid N. (2005). "First Observations of Feeding on Thresher (Alopias vulpinus) and Hammerhead (Sphyrna zygaena) Sharks by Killer Whales (Orcinus orca) Specialising on Elasmobranch Prey". Aquatic Mammals. 31 (1): 83–88. doi:10.1578/AM.31.1.2005.83.
  108. ^ Visser, Ingrid N.; Jo Berghan; Rinie van Meurs & Dagmar Fertl (2000). "Killer Whale (Orcinus orca) Predation on a Shortfin Mako Shark (Isurus oxyrinchus) in New Zealand Waters" (PDF). Aquatic Mammals. 26 (3): 229–231. Archived (PDF) from the original on January 26, 2012. Retrieved May 3, 2014.
  109. ^ Visser, Ingrid N. (1999). "Benthic foraging on stingrays by killer whales (Orcinus orca) in New Zealand waters". Marine Mammal Science. 15 (1): 220–227. doi:10.1111/j.1748-7692.1999.tb00793.x.
  110. ^ Dyste, Leslie (December 15, 2016). "Rare footage shows Killer Whales 'sharing' shark in Monterey Bay". Archived from the original on February 23, 2018. Retrieved February 23, 2018.
  111. ^ Dyer, Z. (2014). "VIDEO: Killer whales hunt tiger shark near Costa Rica's Cocos Island". The Tico Times. Archived from the original on August 24, 2017. Retrieved August 25, 2017.
  112. ^ O'Sullivan, J. B.; T., Mitchell (2000). "A fatal attack on a whale shark Rhincodon typus, by killer whales Orcinus orca off Bahia de Los Angeles, Baja California". American Elasmobranch Society 16th Annual Meeting, June 14–20, 2000. La Paz, B.C.S., México. Archived from the original on February 28, 2010. Retrieved February 18, 2010.
  113. ^ "Great white shark 'slammed' and killed by a pod of killer whales in South Australia". Australian Broadcast Company. February 3, 2015. Archived from the original on July 19, 2015. Retrieved July 10, 2015.
  114. ^ a b Haden, Alexis (June 6, 2017). "Killer whales have been killing great white sharks in Cape waters". The South African. Archived from the original on July 4, 2017. Retrieved June 27, 2017.
  115. ^ Starr, Michell (November 11, 2019). "Incredible Footage Reveals Orcas Chasing Off The Ocean's Most Terrifying Predator". Science Alert. Archived from the original on November 11, 2019. Retrieved November 24, 2019.
  116. ^ Heithaus, Michael (2001). "Predator–prey and competitive interactions between sharks (order Selachii) and dolphins (suborder Odontoceti): a review" (PDF). Journal of Zoology. 253 (1): 53–68. CiteSeerX 10.1.1.404.130. doi:10.1017/S0952836901000061. Archived from the original (PDF) on January 15, 2016. Retrieved January 18, 2010.
  117. ^ Jorgensen, S. J.; et al. (2019). "Killer whales redistribute white shark foraging pressure on seals". Scientific Reports. 9 (1): 6153. Bibcode:2019NatSR...9.6153J. doi:10.1038/s41598-019-39356-2. PMC 6467992. PMID 30992478.
  118. ^ Ankel, Sophia (November 22, 2020). "Hundreds of great white sharks have vanished from South Africa's coast and fearsome orcas are to blame". insider.com. Insider Inc. Retrieved April 30, 2021.
  119. ^ a b c d Ashley Yeager (November 1, 2020). "Clues point to climate change as a culprit in gray whale deaths". The Scientist. Retrieved November 5, 2020.
  120. ^ "Unusual Number of Killer Whales Sighted". San Jose Mercury-News. Bay Area News Group. May 8, 2018. p. B1.
  121. ^ Visser, Ingrid N; Zaeschmar, Jochen; Halliday, Jo; Abraham, Annie; Ball, Phil; Bradley, Robert; Daly, Shamus; Hatwell, Tommy; Johnson, Tammy (2010). "First Record of Predation on False Killer Whales (Pseudorca crassidens) by Killer Whales (Orcinus orca)" (PDF). Aquatic Mammals. 36 (2): 195–204. doi:10.1578/AM.36.2.2010.195. S2CID 85669121. Archived (PDF) from the original on September 15, 2020. Retrieved May 27, 2020.
  122. ^ Ford, J. K. B.; Reeves R. R. (2008). "Fight or flight: antipredator strategies of baleen whales" (PDF). Mammal Review. 38 (1): 50–86. CiteSeerX 10.1.1.573.6671. doi:10.1111/j.1365-2907.2008.00118.x. Archived from the original (PDF) on September 22, 2017.
  123. ^ Santos, Marcos Cesar de Oliveira & Netto, Denis Ferreira (2005). "Killer whale (Orcinus orca) predation on a franciscana dolphin (Pontoporia blainvillei) in Brazilian waters". Latin American Journal of Aquatic Mammals. 4 (1): 69–72. doi:10.5597/lajam00072.
  124. ^ Fox, Alex. "More Than 50 Orcas Hunt and Kill Blue Whale Off Australian Coast". Smithsonian Magazine.
  125. ^ a b Estes, James (February 26, 2009). "Ecological effects of marine mammals". In Perrin, William F. (ed.). Encyclopedia of Marine Mammals. Wursig, Bernd & Thewissen, J. G.M. Academic Press. pp. 357–361. ISBN 978-0-08-091993-5. Archived from the original on May 9, 2016. Retrieved December 30, 2015.
  126. ^ Pitman, Robert L.; et al. (2001). "Killer Whale Predation on Sperm Whales: Observations and Implications". Marine Mammal Science. 17 (3): 494–507. doi:10.1111/j.1748-7692.2001.tb01000.x. Archived from the original on December 11, 2015. Retrieved February 25, 2014.
  127. ^ Estes; et al. (2007). Whales, Whaling, and Ocean Ecosystems. ISBN 978-0-520-24884-7.
  128. ^ a b c Heimlich & Boran 2001, p. 45.
  129. ^ Pinell, Nadine, et al. "Transient Killer Whales – Culprits in the Decline of Sea Otters in Western Alaska? Archived June 30, 2017, at the Wayback Machine" B.C. Cetacean Sightings Network, June 1, 2004. Retrieved March 13, 2010
  130. ^ a b Baird 2002, p. 23.
  131. ^ Killer Whales Develop a Taste For Sea Otters Archived November 7, 2015, at the Wayback Machine Ned Rozell, Article #1418, Alaska Science Forum, December 10, 1998. Retrieved February 26, 2010
  132. ^ Springer, A. M. (2003). "Sequential megafaunal collapse in the North Pacific Ocean: An ongoing legacy of industrial whaling?". Proceedings of the National Academy of Sciences. 100 (21): 12223–12228. Bibcode:2003PNAS..10012223S. doi:10.1073/pnas.1635156100. PMC 218740. PMID 14526101.
  133. ^ Demaster, D; Trites, A; Clapham, P; Mizroch, S; Wade, P; Small, R; Hoef, J (2006). "The sequential megafaunal collapse hypothesis: Testing with existing data". Progress in Oceanography. 68 (2–4): 329–342. Bibcode:2006PrOce..68..329D. doi:10.1016/j.pocean.2006.02.007.
  134. ^ Estes, J. A.; Doak, D. F.; Springer, A. M.; Williams, T. M. (2009). "Causes and consequences of marine mammal population declines in southwest Alaska: a food-web perspective". Philosophical Transactions of the Royal Society B: Biological Sciences. 364 (1524): 1647–1658. doi:10.1098/rstb.2008.0231. PMC 2685424. PMID 19451116.
  135. ^ Carwardine 2001, p. 29.
  136. ^ a b Baird 2002, pp. 61–62.
  137. ^ Visser, Ingrid N.; Smith, Thomas G.; Bullock, Ian D.; Green, Geoffrey D.; Carlsson, Olle G. L.; Imberti, Santiago (2008). "Antarctic peninsula killer whales (Orcinus orca) hunt seals and a penguin on floating ice" (PDF). Marine Mammal Science. 24 (1): 225–234. doi:10.1111/j.1748-7692.2007.00163.x. Archived from the original (PDF) on May 31, 2011.
  138. ^ BBC Nature – Killer whales make waves to hunt seals Archived September 9, 2018, at the Wayback Machine. Bbc.co.uk (October 18, 2011). Retrieved on April 4, 2012.
  139. ^ Baird 2002, p. 124.
  140. ^ Ford, Ellis & Balcomb 2000, p. 19.
  141. ^ Baird 2002, p. 14.
  142. ^ "Whale uses fish as bait to catch seagulls then shares strategy with fellow orcas". Associated Press. September 7, 2005. Archived from the original on March 22, 2010. Retrieved February 18, 2010.
  143. ^ Carwardine 2001, p. 64.
  144. ^ Connelly, Laylan (July 30, 2019). "Videos show killer whales frantically hunting for dolphins off San Clemente". The OCR. Archived from the original on December 10, 2019. Retrieved November 24, 2019.
  145. ^ a b Heimlich & Boran 2001, p. 35.
  146. ^ "Keep Whales Wild". Keep Whales Wild. January 14, 2011. Archived from the original on December 16, 2010. Retrieved February 16, 2011.
  147. ^ a b c d NMFS 2005, p. 12.
  148. ^ a b NMFS 2005, p. 39.
  149. ^ NMFS 2005, p. 13.
  150. ^ a b NMFS 2005, p. 14.
  151. ^ a b NMFS 2005, p. 20.
  152. ^ Foote, A. D.; Osborne, R. W. & Hoelzel, A. (2008). "Temporal and contextual patterns of killer whale (Orcinus orca) call type production". Ethology. 114 (6): 599–606. doi:10.1111/j.1439-0310.2008.01496.x.
  153. ^ a b Kremers, D.; Lemasson, A.; Almunia, J. & Wanker, R. (2012). "Vocal sharing and individual acoustic distinctiveness within a group of captive orcas (Orcinus orca)". Journal of Comparative Psychology. 126 (4): 433–445. doi:10.1037/a0028858. PMID 22866769.
  154. ^ Filatova, Olga A.; Fedutin, Ivan D.; Burdin, Alexandr M.; Hoyt, Erich (2007). "The structure of the discrete call repertoire of killer whales Orcinus orca from Southeast Kamchatka" (PDF). Bioacoustics. 16 (3): 261–280. doi:10.1080/09524622.2007.9753581. S2CID 56304541. Archived (PDF) from the original on July 15, 2011. Retrieved February 23, 2010.
  155. ^ Weiß, Brigitte M.; Ladich, Friedrich; Spong, Paul; Symonds, Helena (2006). "Vocal behaviour of resident killer whale matrilines with newborn calves: The role of family signatures" (PDF). The Journal of the Acoustical Society of America. 119 (1): 627–35. Bibcode:2006ASAJ..119..627W. doi:10.1121/1.2130934. PMID 16454316. Archived from the original (PDF) on May 27, 2011.
  156. ^ a b NMFS 2005, pp. 15–16.
  157. ^ Simon, M.; McGregor, P. K. & Ugarte, F. (2007). "The relationship between the acoustic behaviour and surface activity of killer whales (Orcinus orca) that feed on herring (Clupea harengus)". Acta Ethologica. 10 (2): 47–53. doi:10.1007/s10211-007-0029-7. S2CID 29828311. Archived from the original on September 15, 2020. Retrieved February 4, 2020.
  158. ^ Szondy, David (February 26, 2020). "The smallest killer whale has a large musical repertoire". New Atlas. Archived from the original on February 27, 2020. Retrieved February 27, 2020.
  159. ^ Spear, Kevin. Killer whales: How smart are they? Archived September 8, 2015, at the Wayback Machine Orlando Sentinel, March 7, 2010. Retrieved March 7, 2010
  160. ^ Dunham, Will (October 16, 2017). "Big and brilliant: complex whale behavior tied to brain size". Reuters. Retrieved December 23, 2020.
  161. ^ a b Associated Press. Whale Attack Renews Captive Animal Debate Archived March 5, 2010, at the Wayback Machine CBS News, March 1, 2010. Retrieved March 7, 2010
  162. ^ a b Carwardine 2001, p. 67.
  163. ^ a b Obee & Ellis 1992, p. 42.
  164. ^ "Killer whale games" (PDF). Blackfish Sounder. 13: 5. 2005. Archived from the original (PDF) on October 11, 2007.
  165. ^ Pitman, Robert L. Scientist Has 'Snowball Fight' With a Killer Whale Archived September 15, 2020, at the Wayback Machine. Live Science, February 6, 2009. Retrieved March 7, 2010
  166. ^ Marino, Lori; et al. (2007). "Cetaceans Have Complex Brains for Complex Cognition". PLOS Biology. 5 (e139): e139. doi:10.1371/journal.pbio.0050139. PMC 1868071. PMID 17503965.
  167. ^ Rendell, Luke; Hal Whitehead (2001). "Culture in whales and dolphins". Behavioral and Brain Sciences. 24 (2): 309–324. doi:10.1017/S0140525X0100396X. PMID 11530544. S2CID 24052064. Archived from the original on May 30, 2010. Retrieved March 7, 2010.
  168. ^ a b Ward, Eric J.; Holmes, Elizabeth E.; Balcomb, Ken C. (June 2009). "Quantifying the effects of prey abundance on killer whale reproduction". Journal of Applied Ecology. 46 (3): 632–640. doi:10.1111/j.1365-2664.2009.01647.x.
  169. ^ Bowden, DM; Williams, DD (1984). "Aging". Advances in Veterinary Science and Comparative Medicine. 28: 305–41. doi:10.1016/B978-0-12-039228-5.50015-2. ISBN 9780120392285. PMID 6395674.
  170. ^ Physiological Basis of Aging and Geriatrics, Fourth Edition, Paola S. Timiras, CRC Press, 2013, page 161
  171. ^ a b "Orcas don't do well in captivity. Here's why". Animals. March 25, 2019. Archived from the original on June 6, 2020. Retrieved May 31, 2020.
  172. ^ a b Carwardine 2001, p. 26.
  173. ^ TEGNA. "Oldest Southern Resident killer whale considered dead". KING. Archived from the original on January 3, 2017. Retrieved January 3, 2017.
  174. ^ Podt, Annemieke (December 31, 2016). "Orca Granny: was she really 105?". Archived from the original on October 15, 2018. Retrieved September 11, 2017.
  175. ^ a b Robeck, Todd R.; Willis, Kevin; Scarpuzzi, Michael R.; O'Brien, Justine K. (September 29, 2015). "Comparisons of life-history parameters between free-ranging and captive killer whale (Orcinus orca) populations for application toward species management". Journal of Mammalogy. 96 (5): 1055–1070. doi:10.1093/jmammal/gyv113. PMC 4668992. PMID 26937049. Archived from the original on April 23, 2019.
  176. ^ Jett, John; Ventre, Jeffrey (2015). "Captive killer whale (Orcinus orca) survival". Marine Mammal Science. 31 (4): 1362–1377. doi:10.1111/mms.12225.
  177. ^ NMFS 2005, p. 33.
  178. ^ NMFS 2005, p. 35.
  179. ^ Mitchell, E. and Baker, A. N. (1980). Age of reputedly old Killer Whale, Orcinus orca, 'Old Tom' from Eden, Twofold Bay, Australia, in: W. F. Perrin and A. C. Myrick Jr (eds.): Age determination of toothed whales and sirenians, pp. 143–154 Rep. Int. Whal. Comm. (Special Issue 3), cited in Know the Killer Whale, The Dolphin's Encyclopaedia. Retrieved January 27, 2010
  180. ^ Olesiuk, Peter F.; Ellis, Graeme M. and Ford, John K. B. (2005). Life History and Population Dynamics of Northern Resident Killer Whales (Orcinus orca) in British Columbia Archived April 19, 2011, at the Wayback Machine, Research Document 2005/045, Canadian Science Advisory Secretariat, Fisheries and Oceans Canada. p. 33. Retrieved January 27, 2010
  181. ^ How Southern Resident Killer Whales are Identified Archived November 28, 2009, at the Wayback Machine, Center for Whale Research. Retrieved March 23, 2012
  182. ^ "'Horrified' scientists first to see killer whale infanticide | CBC News". Archived from the original on March 23, 2018. Retrieved March 22, 2018.
  183. ^ "First stranded Orca found in almost 20 years in the Wash". BBC News. January 14, 2020. Archived from the original on January 16, 2020.
  184. ^ a b Ford, Ellis & Balcomb 2000, p. 99.
  185. ^ "Orcas of the Pacific Northwest Are Starving and Disappearing". Archived from the original on July 10, 2018. Retrieved July 9, 2018.
  186. ^ Ford, Ellis & Balcomb 2000, p. 98.
  187. ^ a b M. L. Lyke, Granny's Struggle: When Granny is gone, will her story be the last chapter? Archived September 15, 2020, at the Wayback Machine, Seattle Post Intelligencer, October 14, 2006
  188. ^ a b Le Phuong. Researchers: 7 Orcas Missing from Puget Sound Archived October 28, 2008, at the Wayback Machine, Associated Press. USA Today, October 25, 2008
  189. ^ a b c d e f Pickrell, John (March 2004). "U.S. Navy Sonar May Harm Killer Whales, Expert Says". National Geographic News. Archived from the original on September 9, 2011. Retrieved March 19, 2012.
  190. ^ a b c "Ottawa Sued over Lack of Legislation to Protect B.C. Killer Whales". CBC News. October 9, 2008. Archived from the original on June 26, 2012. Retrieved March 19, 2012.
  191. ^ Ford, Ellis & Balcomb 2000, p. 100.
  192. ^ Research on Orcas Archived September 11, 2012, at archive.today, Raincoast Research Society. Retrieved February 18, 2010
  193. ^ McClure, Robert (October 2, 2003). "State expert urges Navy to stop sonar tests". Seattle Post Intelligencer. Archived from the original on October 4, 2012. Retrieved June 25, 2007.
  194. ^ Williams, Rob (2002). "Behavioural responses of male killer whales to a 'leapfrogging' vessel" (PDF). Journal of Cetacean Resource Management. 4 (3): 305–310. Archived (PDF) from the original on March 6, 2014. Retrieved February 25, 2014.
  195. ^ Keim, Brandon (March 24, 2009). "Unique Killer-Whale Pod Doomed by Exxon Valdez". Wired. Archived from the original on January 6, 2010. Retrieved December 31, 2009.
  196. ^ "Marine Ecology Progress Series 356:269" (PDF). Archived from the original (PDF) on July 28, 2011. Retrieved December 31, 2009.
  197. ^ Carrington, Damian (September 27, 2018). "Orca 'apocalypse': half of killer whales doomed to die from pollution". The Guardian. Archived from the original on September 28, 2018. Retrieved September 28, 2018.
  198. ^ Ford, Ellis & Balcomb 2000, p. 11.
  199. ^ Rollmann, Hans (1999). Religion in Newfoundland and Labrador Archived May 4, 2009, at the Wayback Machine, Newfoundland and Labrador Heritage, Memorial University of Newfoundland. Retrieved January 26, 2010
  200. ^ Tuck, James A. (1971). "An Archaic Cemetery at Port Au Choix, Newfoundland". American Antiquity. 36 (3): 343–358. doi:10.2307/277719. JSTOR 277719.
  201. ^ The orphan boy with his sister, p. 156 in Rubcova, E. S. (1954). Materials on the Language and Folklore of the Eskimoes, Vol. I, Chaplino Dialect. Leningrad: Academy of Sciences of the USSR. Original data: Е.С. Рубцова: Материалы по языку и фольклору эскимосов (чаплинский диалект). Академия Наук СССР. Москва-Ленинград, 1954
  202. ^ Menovshchikov, G. A. (1962). Grammar of the language of Asian Eskimos. Vol. I., pp. 439, 441. Moscow and Leningrad: Academy of Sciences of the USSR. Original data: Г. А. Меновщиков: Грамматиκа языка азиатских эскимосов. Часть первая. Академия Наук СССР. Москва-Ленинград, 1962
  203. ^ a b "Поддержка прав коренных народов Cибири - Spiritual culture subsection of the Eskimos page in the Support for Siberian Indigenous Peoples Rights". nsu.ru (in Russian). Archived from the original on August 30, 2007.
  204. ^ a b Vajda, Edward J. "Siberian Yupik (Eskimo)". East Asian Studies. Archived from the original on October 28, 2016. Retrieved August 7, 2013.
  205. ^ a b Ковалева, Ирина & Богословская, Людмила (December 3, 2002). Животные и отражение их прихода к человеку в самых разных текстах (in Russian). Эхо Москвы. Арсенал. Archived from the original on May 5, 2008. Retrieved April 29, 2008. CS1 maint: discouraged parameter (link) A radio interview with Russian scientists about man and animal, examples taken especially from Asian Eskimos
  206. ^ Miyanaga, T. (2014). （北海道）「シャチ送り」の遺構か 礼文島の遺跡で出土. Asahi Shimbun (in Japanese).
  207. ^ Gaius Plinius Secundus. Historia Naturalis 9.5.12 Archived September 15, 2020, at the Wayback Machine (Latin), in Bill Thayer's LacusCurtius: Into the Roman World Archived May 24, 2012, at archive.today. (See also an English translation Archived June 4, 2011, at the Wayback Machine by John Bostock and Henry Thomas Riley, 1855.) Retrieved February 19, 2010.
  208. ^ "Orca shares the waves with local surfer". 3 News. September 12, 2008. Archived from the original on July 24, 2011. Retrieved October 13, 2011.
  209. ^ Cherry-Garrard, Apsley (2004). The Worst Journey in the World:Antarctic 1910–1913. Globe Pequot. p. 92. ISBN 978-1-59228-212-8.
  210. ^ "Boy survives bump from killer whale". The Seattle Times. The Associated Press. August 18, 2005. Archived from the original on April 2, 2011. Retrieved January 3, 2010.
  211. ^ a b "ABC News: Killer Whale Attacks SeaWorld Trainer". ABC News. November 30, 2006. Archived from the original on February 28, 2010. Retrieved January 3, 2010.
  212. ^ SeaWorld trainer killed by killer whale Archived April 3, 2010, at the Wayback Machine", CNN, February 25, 2010, Retrieved September 9, 2010
  213. ^ NMFS 2005, p. 41.
  214. ^ Killer Whales Destroyed: VP-7 Accomplishes Special Task, Naval Aviation News, December 1956, p. 19. Reproduced at Longevity and Causes of Death Archived June 19, 2010, at the Wayback Machine, SeaWorld/Busch Gardens ANIMALS. Retrieved January 11, 2010
  215. ^ "Naval War Declared Against Killer Whales". The Science News-Letter. 69 (24): 374. 1956. doi:10.2307/3936617. JSTOR 3936619.
  216. ^ Victoria Gill (November 2020). "Have rogue orcas really been attacking boats in the Atlantic?". BBC News.
  217. ^ Francis & Hewlett 2007, pp. 58–59.
  218. ^ Baird 2002, pp. 73–80.
  219. ^ Heimlich & Boran 2001, p. 11.
  220. ^ Wood, Daniel (February 24, 2010). "Death of Sea World trainer: Do 'killer whales' belong in theme parks?". The Christian Science Monitor. Archived from the original on May 13, 2012. Retrieved March 19, 2012.
  221. ^ Movie-Star Whale Keiko Dies of Pneumonia. Archived June 7, 2020, at the Wayback Machine Associated Press. Published December 13, 2003. Retrieved June 7, 2020.
  222. ^ "Orphaned orca's reunion with family celebrated". Canadian Broadcasting Corporation. July 13, 2007. Archived from the original on November 6, 2015. Retrieved November 6, 2007.
  223. ^ McClure, Robert (March 11, 2006). "Luna the orca killed by tugboat". Seattle Post-Intelligencer. Seattle, Washington: Hearst Corporation. Archived from the original on August 11, 2011. Retrieved April 8, 2009.
  224. ^ "海域自然環境保全基礎調査 - 海棲動物調査報告書, (2)- 19. シャチ Orcinus orca (Limaeus,1758)マイルカ科" (PDF). 自然環境保全基礎調査: 54. 1998. Archived (PDF) from the original on July 17, 2015. Retrieved January 14, 2015.
  225. ^ a b Obee & Ellis 1992, p. 34.
  226. ^ シャチ騒動 (in Japanese). Osaka College of Eco & Animals. 2011. Archived from the original on December 24, 2014. Retrieved December 24, 2014.
  227. ^ "Stranding Base (1901-2012) for Hyogo Prefecture". The Whale Laboratory of Shimonoseki. 2014. Archived from the original on December 24, 2014. Retrieved December 24, 2014.
  228. ^ "Stranding Date Base (1901-2012) for Chiba Prefecture". The Whale Laboratory of Shimonoseki. 2014. Archived from the original on January 9, 2015. Retrieved January 9, 2015.
  229. ^ Kaiya Z.; Leatherwood S.; Jefferson A.T. (2002). Perrin F.W.; Reeves R.R.; Dolar L.L.M.; Jefferson A.T.; Marsh H.; Wang Y.J.; Estacion J. (eds.). "Report of the Second Workshop on The Biology and Conservation of Small Cetaceans and Dugongs of South-East Asia" (PDF). CMS Technical Series Publication Nº 9 at Convention on Migratory Species. Archived from the original (PDF) on March 4, 2016. Retrieved December 24, 2014.
  230. ^ a b Reeves, Randall; Whitehead, Hal (2005). "Killer whales and whaling: the scavenging hypothesis". Biology Letters. 1 (4): 415–8. doi:10.1098/rsbl.2005.0348. PMC 1626385. PMID 17148221.
  231. ^ "Home". Be Whale Wise. Archived from the original on October 31, 2019. Retrieved October 31, 2019.
  232. ^ a b c d Lachmuth, Cara L.; Barrett-Lennard, Lance G.; Steyn, D.Q.; Milsom, William K. (April 2011). "Estimation of southern resident killer whale exposure to exhaust emissions from whale-watching vessels and potential adverse health effects and toxicity thresholds". Marine Pollution Bulletin. 62 (4): 792–805. doi:10.1016/j.marpolbul.2011.01.002. PMID 21276987.
  233. ^ "Boats to Maintain Greater Distance from Killer Whales | Whales online". November 8, 2017. Archived from the original on March 30, 2019. Retrieved March 14, 2019.
  234. ^ NMFS 2005, pp. 43–44.
  235. ^ Rose, N. A. (2011). "Killer Controversy: Why Orcas Should No Longer Be Kept in Captivity" (PDF). Humane Society International and the Humane Society of the United States. Archived (PDF) from the original on December 30, 2017. Retrieved December 21, 2014.
  236. ^ "Orcas in captivity" (PDF). Whale and Dolphin Conservation Society. Archived from the original (PDF) on July 6, 2010. Retrieved January 26, 2010.
  237. ^ "Blackfish". Rotten Tomatoes. Archived from the original on November 21, 2013. Retrieved November 23, 2013.
  238. ^ Hoyt, Eric (1992). "The Performing Orcas - why the show must stop". Whale and Dolphin Conservation Society. Archived from the original on July 5, 2017. Retrieved September 2, 2017.
  239. ^ Zimmerman, Tim (2011). "The Killer in the Pool". The Best American Sampler 2011. Houghton Mifflin Harcourt. p. 336.
  240. ^ "Corpse Is Found on Whale". The New York Times. July 7, 1999. Archived from the original on June 13, 2012. Retrieved September 11, 2011.
  241. ^ "SeaWorld trainer killed by killer whale". CNN. February 25, 2010. Archived from the original on March 8, 2010. Retrieved March 11, 2010.
  242. ^ "Tilikum the SeaWorld orca's cause of death revealed - National | Globalnews.ca". February 3, 2017. Archived from the original on August 31, 2017. Retrieved July 26, 2017.
  243. ^ "SeaWorld to End Controversial Orca Shows and Breeding". National Geographic News. March 17, 2016. Archived from the original on April 20, 2016. Retrieved September 27, 2016.
  244. ^ Stevens, Blair (June 11, 2020). "Even years after Blackfish, SeaWorld still has Orcas". Retrieved December 23, 2020.

Further reading

  • Baird, Robin W. (2002). Killer Whales of the World. Stillwater, MN.: Voyageur Press. ISBN 978-0-7603-2654-1.
  • Carwardine, Mark (2001). Killer Whales. London: BBC Worldwide. ISBN 978-0-7894-8266-2.
  • Ford, John K. B. (2002). "Killer Whale". Encyclopedia of Marine Mammals. Academic Press. pp. 669–675. ISBN 0-12-551340-2.
  • Ford, John K. B.; Ellis, Graeme M.; Balcomb, Kenneth C. (2000). Killer Whales (Second ed.). Vancouver, BC: UBC Press. ISBN 978-0-7748-0800-2.
  • Ford, John K. B.; Ellis, Graeme M. (2006). "Selective foraging by fish-eating killer whales Orcinus orca in British Columbia". Marine Ecology Progress Series. 316: 185–199. Bibcode:2006MEPS..316..185F. doi:10.3354/meps316185.
  • Francis, Daniel; Hewlett, Gil (2007). Operation Orca: Springer, Luna and the Struggle to Save West Coast Killer Whales. Madeira Park, B.C.: Harbour Publishing. ISBN 978-1-55017-426-7.
  • Heimlich, Sara; Boran, James (2001). Killer Whales. Stillwater, MN: Voyageur Press. ISBN 978-0-89658-545-4.
  • Heptner, V. G.; Nasimovich, A. A.; Bannikov, A. G.; Hoffmann, Robert S. (1996). Mammals of the Soviet Union. II, part 3. Washington D.C.: Smithsonian Institution Libraries and National Science Foundation. ISBN 978-1-886106-81-9.
  • Hoyt, Erich (August 1984). "The Whales Called "Killer"". National Geographic. Vol. 166 no. 2. pp. 220–237. ISSN 0027-9358. OCLC 643483454.
  • NMFS (2005). "Conservation Plan for Southern Resident Killer Whales (Orcinus orca)" (PDF). Seattle, U.S.: National Marine Fisheries Service (NMFS) Northwest Regional Office. Archived from the original (PDF) on June 26, 2008. Retrieved January 2, 2009.
  • Obee, Bruce; Ellis, Graeme (1992). Elaine Jones (ed.). Guardians of the Whales: The Quest to Study Whales in the Wild. North Vancouver, British Columbia: Whitecap Books. ISBN 978-1-55110-034-0.
  • Hoyt, Erich (1998), Orca: The Whale Called Killer Camden House Publishing, ISBN 978-0-920656-25-9
  • Kirkevold, B. C.; J. S. Lockard (1986). Behavioral Biology of Killer Whales. Alan R. Liss Inc. ISBN 978-0-8451-3100-8.

External links

  • Orca-Live – Orcas in Johnstone Strait, British Columbia
  • Salish Sea Hydrophone Network – Listen live to orcas in Washington State, U.S.
  • Keep Whales Wild
  • Killer whale photos
  • Why are orca called killer whales?, HowStuffWorks.com, article by Jacob Silverman
  • Voices in the Sea - Sounds of the Orca (Killer Whale)
  • Killer whale devours great white shark
  • Pod of orcas vs group of great whites near Seal Island, South Africa
  • Orcas Preying On Dolphins (Caught On Drone), off the coast of San Clemente
  • Orcas vs Sperm Whales
  • Watch: Killer Whales Charge Blue Whale (Rare Drone Footage) | National Geographic