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The orca (''Orcinus orca''), or killer whale, is a
toothed whale
The toothed whales (also called odontocetes, systematic name Odontoceti) are a parvorder of cetaceans that includes dolphins, porpoises, and all other whales with teeth, such as beaked whales and the sperm whales. 73 species of toothed wha ...
and the largest member of the oceanic dolphin
Oceanic dolphins or Delphinidae are a widely distributed family of dolphins that live in the sea. Close to forty extant species are recognised. They include several big species whose common names contain "whale" rather than "dolphin", such as the ...
family. The only extant
Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to:
* Extant hereditary titles
* Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English
* Exta ...
species in the genus ''Orcinus
''Orcinus'' is a genus of Delphinidae, the family of carnivorous marine mammals known as dolphins. It includes the largest delphinid species, ''Orcinus orca'', known as the orca or killer whale. Two extinct species are recognised, '' Orcinus pal ...
'', it is recognizable by its black-and-white-patterned body. A cosmopolitan species
In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en ...
, it inhabits a wide range of marine environments, from Arctic
The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...
to Antarctic regions to tropical seas.
Orcas are apex predator
An apex predator, also known as a top predator or superpredator, is a predator at the top of a food chain, without natural predators of its own.
Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the hig ...
s with a diverse diet. Individual populations often specialize in particular types of prey, including fish
A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
, shark
Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...
s, rays
Ray or RAY may refer to:
Fish
* Ray (fish), any cartilaginous fish of the superorder Batoidea
* Ray (fish fin anatomy), the bony or horny spine on ray-finned fish
Science and mathematics
* Half-line (geometry) or ray, half of a line split at an ...
, and marine mammal
Marine mammals are mammals that rely on marine ecosystems for their existence. They include animals such as cetaceans, pinnipeds, sirenians, sea otters and polar bears. They are an informal group, unified only by their reliance on marine enviro ...
s such as seals
Seals may refer to:
* Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly:
** Earless seal, or "true seal"
** Fur seal
* Seal (emblem), a device to impress an emblem, used as a means of a ...
, dolphins, and whales. They are highly social
Social organisms, including human(s), live collectively in interacting populations. This interaction is considered social whether they are aware of it or not, and whether the exchange is voluntary or not.
Etymology
The word "social" derives fro ...
, with some populations forming stable matrilineal
Matrilineality, at times called matriliny, is the tracing of kinship through the female line. It may also correlate with a social system in which people identify with their matriline, their mother's lineage, and which can involve the inheritan ...
family groups (pods). Their sophisticated hunting techniques and vocal behaviors, often unique to specific groups and passed down from generation to generation, are considered to be manifestations of animal culture
Animal culture can be defined as the ability of non-human animals to learn and transmit behaviors through processes of social or cultural learning.
Culture is increasingly seen as a process, involving the social transmittance of behavior among p ...
.
The International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
(IUCN) lists the orca's conservation status
The conservation status of a group of organisms (for instance, a species) indicates whether the group still exists and how likely the group is to become extinct in the near future. Many factors are taken into account when assessing conservation ...
as data deficient
A data deficient (DD) species is one which has been categorized by the International Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment of conservation status to be made. This does not necessaril ...
as multiple orca types may represent distinct species. Some local populations are threatened
A threatened species is any species (including animals, plants and fungi) which is vulnerable to extinction in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensatio ...
or endangered
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...
due to prey depletion, habitat loss
Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...
, pollution (by PCBs
Polychlorinated biphenyls (PCBs) are organochlorine compounds with the formula C12 H10−''x'' Cl''x''; they were once widely used in the manufacture of carbonless copy paper, as heat transfer fluids, and as dielectric and coolant fluids f ...
), captures for marine park
A marine park is a designated park consisting of an area of sea (or lake) set aside to achieve ecological sustainability, promote marine awareness and understanding, enable marine recreational activities, and provide benefits for Indigenous peo ...
s, and conflicts with fisheries. In late 2005, the southern resident orca
The southern resident orcas, also known as the southern resident killer whales (SRKW), are the smallest of four communities of the exclusively fish-eating ecotype of orca in the northeast Pacific Ocean. The southern resident orcas form a closed s ...
s were added on the U.S. Endangered Species list.
Orcas rarely pose a threat to humans, and no fatal attack has been recorded in the wild. However, captive orcas have injured or killed their handlers in marine theme parks.
Naming
Orcas are often referred to as "killer whales" because ancient sailors saw them hunt larger whales. Since the 1960s, the term "orca" has increasingly replaced "killer whale" in common usage. Although some sources suggests that ''Orcinus'' means 'of the kingdom of the dead', theInternational Code of Zoological Nomenclature
The International Code of Zoological Nomenclature (ICZN) is a widely accepted Convention (norm), convention in zoology that rules the formal scientific name, scientific naming of organisms treated as animals. It is also informally known as the I ...
(ICZN) mentions that the name orca originates from Latin word ''orca'', meaning 'a large-bellied pot.' ''Orcinus'' is a derived form created by adding a masculine suffix to it. Ancient Romans
The Roman people was the ethnicity and the body of Roman citizenship, Roman citizens
(; ) during the Roman Kingdom, the Roman Republic, and the Roman Empire. This concept underwent considerable changes throughout the long history of the Roman ...
originally used ''orca'' ( ''orcae'') for these animals, possibly borrowing Ancient Greek
Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...
(''óryx''), which was used for various whale species potentially including the narwhal
The narwhal (''Monodon monoceros'') is a species of toothed whale native to the Arctic. It is the only member of the genus ''Monodon'' and one of two living representatives of the family Monodontidae. The narwhal is a stocky cetacean with a ...
.
They are sometimes referred to as 'blackfish', a term also used for other cetaceans. Historically, 'grampus' was another name for the species, though it is now rarely used. This usage should not be confused with the genus ''Grampus'', which includes only Risso's dolphin
Risso's dolphin (''Grampus griseus'') is a marine mammal and dolphin, the only species of the genus ''Grampus''. Some of the most closely related species to these dolphins include: pilot whales (''Globicephala'' spp.), pygmy killer whales (''Fere ...
(''Grampus griseus'').
Taxonomy
''Orcinus orca'' is the onlyextant
Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to:
* Extant hereditary titles
* Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English
* Exta ...
species recognized in the genus ''Orcinus
''Orcinus'' is a genus of Delphinidae, the family of carnivorous marine mammals known as dolphins. It includes the largest delphinid species, ''Orcinus orca'', known as the orca or killer whale. Two extinct species are recognised, '' Orcinus pal ...
'' and one of many species originally described by Carl Linnaeus
Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
in his landmark 1758 10th edition of ''Systema Naturae''. Conrad Gessner
Conrad Gessner (; ; 26 March 1516 – 13 December 1565) was a Swiss physician, naturalist, bibliographer, and philologist. Born into a poor family in Zürich, Switzerland, his father and teachers quickly realised his talents and supported him t ...
wrote the first scientific description of an orca in his ''Piscium & aquatilium animantium natura'' of 1558, part of the larger ''Historia animalium
''History of Animals'' (, ''Ton peri ta zoia historion'', "Inquiries on Animals"; , "History of Animals") is one of the major texts on biology by the ancient Greek philosopher Aristotle. It was written in sometime between the mid-fourth centur ...
'', based on examination of a dead stranded animal in the Bay of Greifswald
The Bay of GreifswaldZum Wal in der Marienkirche
(in German). St. Mary's Church, Greifswald. Retrieved February 16, 2010 The orca is one of 35 species in the oceanic dolphin family, which first appeared about 11 million years ago. The orca lineage probably branched off shortly thereafter. Although it has morphological similarities with the
Status of Killer Whales in Canada
. Contract report to the Committee on the Status of Endangered Wildlife in Canada, Ottawa, ON, Canada. Also published a
Status of Killer Whales, ''Orcinus orca'', in Canada
''The Canadian Field-Naturalist'' 115 (4) (2001), 676–701. Retrieved January 26, 2010.
Orcas are the largest extant members of the dolphin family. Males typically range from long and weigh in excess of . Females are smaller, generally ranging from and weighing about . Orcas may attain larger sizes as males have been recorded at and females at . Large males can reach a weight of over . Calves at birth weigh about and are about long. The skeleton of the orca is typical for an oceanic dolphin, but more robust. They can also reach speeds of up to
With their distinctive pigmentation, adult orcas are rarely confused with any other species. When seen from a distance, juveniles can be confused with 
Orca
Orcas are found in all oceans and most seas. Due to their enormous range, numbers, and density, relative distribution is difficult to estimate, but they clearly prefer higher latitudes and coastal areas over 
In the Antarctic, orcas range up to the edge of the
Orcas also prey on larger species such as
Day-to-day orca behaviour generally consists of foraging, travelling, resting and socializing. Orcas frequently engage in Whale surfacing behavior, 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 (animal behavior), play. Spyhopping is a behaviour in which a whale holds its head above water to view its surroundings. Resident orcas swim alongside
Like all cetaceans, orcas 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.
Northeast Pacific resident groups tend to be much more vocal than transient groups in the same waters. Residents feed primarily on Chinook and Chum salmon, chum salmon, which are insensitive to orca calls (inferred from the audiogram of Atlantic salmon). In contrast, the
People who have interacted closely with orcas offer numerous Anecdotal evidence, anecdotes demonstrating the whales' curiosity, playfulness, and ability to solve problems. Alaskan orcas have not only learned how to steal fish from Longline fishing, longlines, but have also overcome a variety of techniques designed to stop them, such as the use of unbaited lines as decoys. 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. The tactic worked initially, but the orcas adapted quickly and split into groups.
In other anecdotes, researchers describe incidents in which wild orcas playfully tease humans by repeatedly moving objects the humans are trying to reach, or suddenly start to toss around a chunk of ice after a human throws a snowball.
The orca's use of dialects and the passing of other learned behaviours from generation to generation have been described as a form of
In 2008, the
Researchers: 7 Orcas Missing from Puget Sound
, Associated Press. USA Today, October 25, 2008 Scientist Ken Balcomb has extensively studied orcas since 1976; he is the research biologist responsible for discovering Marine mammals and sonar#Naval sonar-linked incidents, U.S. Navy sonar may harm orcas. He studied orcas from the Center for Whale Research, located in Friday Harbor, Washington, Friday Harbor, Washington. He was also able to study orcas from "his home porch perched above Puget Sound, where the animals hunt and play in summer months". In May 2003, Balcomb (along with other whale watching, whale watchers near the Puget Sound coastline) noticed uncharacteristic behaviour displayed by the orcas. The whales seemed "agitated and were moving haphazardly, attempting to lift their heads free of the water" to escape the sound of the sonars. "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 distant, Balcomb said." The impact of sonar waves on orcas 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. 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. 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 orcas aside from the laws already in place. In response to this decision, six environmental groups sued the federal government, claiming orcas were facing threats along the British Columbia Coast including increased boat traffic, water toxic wastes, and low salmon population, and the federal government did nothing to protect them. Underwater acoustics, Underwater noise from shipping, drilling, and other human activities is a significant concern in some key orca habitats, including Johnstone Strait and Haro Strait. In the mid-1990s, loud underwater noises from salmon farms were used to deter seals. Orcas also avoided the surrounding waters. High-intensity sonar used by the United States Navy, Navy disturbs orcas along with other marine mammals. Orcas are popular with whale watching, whale watchers, which may stress the whales and alter their behaviour, particularly if boats approach too closely or block their lines of travel. The Exxon Valdez oil spill, ''Exxon Valdez'' oil spill adversely affected orcas 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 orcas. 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. Orcas are included in Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning international trade (including in parts/derivatives) is regulated.
In Western cultures, orcas were historically feared as dangerous, savage predators. The first written description of an orca 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." (see citation in section #Naming, "Naming", above).Pliny the Elder, Gaius Plinius Secundus
''Historia Naturalis'' 9.5.12
(Latin), in Bill Thayer's
''. (See also a
English translation
by John Bostock (physician), John Bostock and Henry Thomas Riley, 1855.) Retrieved February 19, 2010. Of the very few confirmed attacks on humans by wild orcas, none have been fatal. In one instance, orcas tried to tip ice floes on which a dog team and Herbert Ponting, photographer of the Terra Nova Expedition were standing. The sled dogs' barking is speculated to have sounded enough like seal calls to trigger the orca's hunting curiosity. In the 1970s, a surfer in California was bitten, but the Orca then retreated, and in 2005, a boy in Alaska who was splashing in a region frequented by harbour seals was bumped by an orca that apparently misidentified him as prey.
Between 1964 and 1976, 50 orcas from the Pacific Northwest were captured for display in Aquarium, 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 Wildlife photo-identification, photo-identification techniques, individuals were named and tracked over decades.
Bigg's techniques also revealed the Pacific Northwest population was in the low hundreds rather than the thousands that had been previously assumed. The southern resident community alone had lost 48 of its members to captivity; by 1976, only 80 remained. In the Pacific Northwest, the species that had unthinkingly been targeted became a cultural icon within a few decades.
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 orcas 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 (whale), Keiko was returned to the coast of his native
The orca's Animal intelligence, intelligence, trainability, striking appearance, playfulness in captivity and sheer size have made it a popular exhibit at aquaria and Marine mammal park, 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.
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. 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 orcas. 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. 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 orca behaviour, see #Behaviour, above. Wild orcas may travel up to in a day, and critics say the animals are too big and intelligent to be suitable for captivity.Associated Press
Whale Attack Renews Captive Animal Debate
''CBS News'', March 1, 2010. Retrieved March 7, 2010 Captives occasionally act aggressively towards themselves, their tankmates, or humans, which critics say is a result of stress (medicine), stress. Between 1991 and 2010, the bull orca known as Tilikum (orca), Tilikum was involved in the death of three people, and was featured in the critically acclaimed 2013 film Blackfish (film), ''Blackfish''. Tilikum lived at SeaWorld from 1992 until his death in 2017. In March 2016, SeaWorld announced that they would be ending their orca breeding program and their theatrical shows. However, as of 2020, theatrical shows featuring orcas are still ongoing.
Orca-Live
– Orcas in Johnstone Strait, British Columbia
Salish Sea Hydrophone Network
– Listen live to orcas in Washington State, U.S.
Keep Whales Wild
, HowStuffWorks.com, article by Jacob Silverman
Orca devours great white shark
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 {{Featured article Orcas, Cosmopolitan mammals Animals that use echolocation Mammals described in 1758 Articles containing video clips Taxa named by Carl Linnaeus
(in German). St. Mary's Church, Greifswald. Retrieved February 16, 2010 The orca is one of 35 species in the oceanic dolphin family, which first appeared about 11 million years ago. The orca lineage probably branched off shortly thereafter. Although it has morphological similarities with the
false killer whale
The false killer whale (''Pseudorca crassidens'') is a species of oceanic dolphin that is the only extant representative of the genus ''Pseudorca''. It is found in oceans worldwide but mainly in tropical regions. It was first species descriptio ...
, the pygmy killer whale
The pygmy killer whale (''Feresa attenuata'') is a poorly known and rarely seen oceanic dolphin. It is the monotypic taxon, only species in the genus ''Feresa''. It derives its common name from sharing some physical characteristics with the orca ...
and the pilot whale
Pilot whales are cetaceans belonging to the genus ''Globicephala''. The two Extant taxon, extant species are the long-finned pilot whale (''G. melas'') and the short-finned pilot whale (''G. macrorhynchus''). The two are not readily distinguish ...
s, a study of cytochrome b gene sequences indicates that its closest extant relatives are the snubfin dolphins of the genus ''Orcaella
The snubfin dolphins (''Orcaella'') are a genus of cetaceans containing two members: the Irrawaddy dolphin (''Orcaella brevirostris'') and the Australian snubfin dolphin (''Orcaella heinsohni''). The genus was long believed to be monotypic with t ...
''.
However, a more recent (2018) study places the orca as a sister taxon
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and ...
to the Lissodelphininae, a clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
that includes '' Lagenorhynchus'' and '' Cephalorhynchus''. In contrast, a 2019 phylogenetic study found the orca to be the second most basal member of the Delphinidae, with only the Atlantic white-sided dolphin
The Atlantic white-sided dolphin (''Lagenorhynchus acutus'') is a distinctively coloured dolphin found in the cool to temperate waters of the North Atlantic Ocean.
Description
The Atlantic white-sided dolphin is a relatively small dolphin. At ...
(''Leucopleurus acutus'') being more basal.
Types
The three to five types of orcas may be distinct enough to be considered different races,Status of Killer Whales in Canada
. Contract report to the Committee on the Status of Endangered Wildlife in Canada, Ottawa, ON, Canada. Also published a
Status of Killer Whales, ''Orcinus orca'', in Canada
''The Canadian Field-Naturalist'' 115 (4) (2001), 676–701. Retrieved January 26, 2010.
subspecies
In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...
, or possibly even species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
(see Species problem
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
). The IUCN
The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
reported in 2008, "The taxonomy
image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy
Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...
of this genus is clearly in need of review, and it is likely that ''O. orca'' will be split into a number of different species or at least subspecies over the next few years." Although large variation in the ecological distinctiveness of different orca groups complicate simple differentiation into types, research off the west coast of North America has identified fish-eating "residents", mammal-eating "transients" and "offshores". Other populations have not been as well studied, although specialized fish and mammal eating orcas have been distinguished elsewhere. Mammal-eating orcas in different regions were long thought likely to be closely related, but genetic testing has refuted this hypothesis.
A 2024 study supported the elevation of Eastern North American resident and transient orcas as distinct species, ''O. ater'' and ''O. rectipinnus'' respectively. The Society for Marine Mammalogy
The Society for Marine Mammalogy was founded in 1981 and is the largest international association of marine mammal scientists in the world.
Mission
The mission of the Society for Marine Mammalogy (SMM) is to promote the global advancement of mari ...
declined to recognize the two species, citing uncertainty as to whether the types constituted unique species or subspecies. "Pending a more complete global review and revision", the Society provisionally recognized them as subspecies ''Orcinus orca ater'' and ''O. o. rectipinnus'', with ''O. o. orca'' as the nominate subspecies
In biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology), but that can successfully interbreed. ...
.
Four types have been documented in the Antarctic
The Antarctic (, ; commonly ) is the polar regions of Earth, polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is antipodes, diametrically opposite of the Arctic region around the North Pole.
The Antar ...
, Types A–D. Two dwarf species, named '' Orcinus nanus'' and '' Orcinus glacialis'', were described during the 1980s by Soviet researchers, but most cetacean researchers are skeptical about their status. Complete mitochondrial sequencing indicates the two Antarctic groups (types B and C) should be recognized as distinct species, as should the North Pacific transients, leaving the others as subspecies pending additional data. A 2019 study of Type D orcas also found them to be distinct from other populations and possibly even a unique species.
Characteristics
Orcas are the largest extant members of the dolphin family. Males typically range from long and weigh in excess of . Females are smaller, generally ranging from and weighing about . Orcas may attain larger sizes as males have been recorded at and females at . Large males can reach a weight of over . Calves at birth weigh about and are about long. The skeleton of the orca is typical for an oceanic dolphin, but more robust. They can also reach speeds of up to
With their distinctive pigmentation, adult orcas are rarely confused with any other species. When seen from a distance, juveniles can be confused with false killer whale
The false killer whale (''Pseudorca crassidens'') is a species of oceanic dolphin that is the only extant representative of the genus ''Pseudorca''. It is found in oceans worldwide but mainly in tropical regions. It was first species descriptio ...
s or Risso's dolphin
Risso's dolphin (''Grampus griseus'') is a marine mammal and dolphin, the only species of the genus ''Grampus''. Some of the most closely related species to these dolphins include: pilot whales (''Globicephala'' spp.), pygmy killer whales (''Fere ...
s. The orca is mostly black but with sharply bordered white areas. The entire lower jaw is white and from here, the colouration stretches across the underside to the genital area; narrowing and expanding some, and extending into lateral flank patches close to the end. The tail fluke (fin) is also white on the underside, while the eyes have white oval-shaped patches behind and above them, and a grey or white "saddle patch" exists behind the dorsal fin and across the back. Males and females also have different patterns of black and white skin in their genital areas. In newborns, the white areas are yellow or orange coloured. Antarctic orcas may have pale grey to nearly white backs. Some Antarctic orcas are brown and yellow due to diatoms
A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...
in the water. Both albino
Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos.
Varied use and interpretation of ...
and melanistic
Melanism is the congenital excess of melanin in an organism resulting in dark pigment.
Pseudomelanism, also called abundism, is another variant of pigmentation, identifiable by dark spots or enlarged stripes, which cover a large part of the bod ...
orcas have been documented.
Orca pectoral fin
Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...
s are large and rounded, resembling paddles, with those of males significantly larger than those of females. Dorsal fin
A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...
s also exhibit sexual dimorphism
Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
, with those of males about high, more than twice the size of the female's, with the male's fin more like an elongated isosceles triangle
In geometry, an isosceles triangle () is a triangle that has two Edge (geometry), sides of equal length and two angles of equal measure. Sometimes it is specified as having ''exactly'' two sides of equal length, and sometimes as having ''at le ...
, whereas the female's is more curved. In the skull, adult males have longer lower jaws than females, as well as larger occipital crests. The snout is blunt and lacks the beak of other species. The orca's teeth are very strong, and its jaws exert a powerful grip; the upper teeth fall into the gaps between the lower teeth when the mouth is closed. The firm middle and back teeth hold prey in place, while the front teeth are inclined slightly forward and outward to protect them from powerful jerking movements.
Orcas have good eyesight above and below the water, excellent hearing, and a good sense of touch. They have exceptionally sophisticated echolocation abilities, detecting the location and characteristics of prey and other objects in the water by emitting clicks and listening for echoes, as do other members of the dolphin family. The mean body temperature of the orca is . Like most marine mammals, orcas have a layer of insulating blubber
Blubber is a thick layer of Blood vessel, vascularized adipose tissue under the skin of all cetaceans, pinnipeds, penguins, and sirenians. It was present in many marine reptiles, such as Ichthyosauria, ichthyosaurs and plesiosaurs.
Description ...
ranging from thick beneath the skin. The pulse is about 60 heartbeats per minute when the orca is at the surface, dropping to 30 beats/min when submerged.
An individual orca can often be identified from its dorsal fin and saddle patch. Variations such as nicks, scratches, and tears on the dorsal fin and the pattern of white or grey in the saddle patch are unique. Published directories contain identifying photographs and names for hundreds of North Pacific animals. Photographic identification has enabled the local population of orcas to be counted each year rather than estimated, and has enabled great insight into life cycles and social structures.
Range and habitat
Orcas are found in all oceans and most seas. Due to their enormous range, numbers, and density, relative distribution is difficult to estimate, but they clearly prefer higher latitudes and coastal areas over pelagic
The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...
environments. Areas which serve as major study sites for the species include the coasts of Iceland
Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...
, Norway, the Valdés Peninsula
The Valdes Peninsula (Spanish: ''Península Valdés'') is a peninsula into the Atlantic Ocean in the Viedma Department of north-east Chubut Province, Argentina. It is an important nature reserve which was listed as a World Heritage Site by UNESC ...
of Argentina, the Crozet Islands
The Crozet Islands (; or, officially, ''Archipel Crozet'') are a sub-Antarctic archipelago of small islands in the southern Indian Ocean. They form one of the five administrative districts of the French Southern and Antarctic Lands.
History ...
, New Zealand and parts of the west coast of North America, from California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
to Alaska
Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
. Systematic surveys indicate the highest densities of orcas (>0.40 individuals per 100 km2) in the northeast Atlantic around the Norwegian coast, in the north Pacific along the Aleutian Islands
The Aleutian Islands ( ; ; , "land of the Aleuts"; possibly from the Chukchi language, Chukchi ''aliat'', or "island")—also called the Aleut Islands, Aleutic Islands, or, before Alaska Purchase, 1867, the Catherine Archipelago—are a chain ...
, the Gulf of Alaska
The Gulf of Alaska ( Tlingit: ''Yéil T'ooch’'') is an arm of the Pacific Ocean defined by the curve of the southern coast of Alaska, stretching from the Alaska Peninsula and Kodiak Island in the west to the Alexander Archipelago in the ...
and in the Southern Ocean
The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the world ocean, generally taken to be south of 60th parallel south, 60° S latitude and encircling Antarctica. With a size of , it is the seco ...
off much of the coast of Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...
. They are considered "common" (0.20–0.40 individuals per 100 km2) in the eastern Pacific along the coasts of British Columbia
British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
, Washington
Washington most commonly refers to:
* George Washington (1732–1799), the first president of the United States
* Washington (state), a state in the Pacific Northwest of the United States
* Washington, D.C., the capital of the United States
** A ...
and Oregon
Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...
, in the North Atlantic Ocean around Iceland
Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...
and the Faroe Islands
The Faroe Islands ( ) (alt. the Faroes) are an archipelago in the North Atlantic Ocean and an autonomous territory of the Danish Realm, Kingdom of Denmark. Located between Iceland, Norway, and the United Kingdom, the islands have a populat ...
.
In the Antarctic, orcas range up to the edge of the pack ice
Pack or packs may refer to:
Music
* Packs (band), a Canadian indie rock band
* ''Packs'' (album), by Your Old Droog
* ''Packs'', a Berner album
Places
* Pack, Styria, defunct Austrian municipality
* Pack, Missouri, United States (US)
* ...
and are believed to venture into the denser pack ice, finding open leads
Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...
much like beluga
Beluga may refer to:
Animals
*Beluga (sturgeon)
* Beluga whale
Vehicles
* Airbus Beluga, a large transport airplane
* Airbus BelugaXL, a larger transport airplane
* Beluga-class submarine, a class of Russian SSA diesel-electric submarine
* U ...
whales in the Arctic. However, orcas are merely seasonal visitors to Arctic waters, and do not approach the pack ice in the summer. With the rapid Arctic sea ice
The Arctic ice pack is the sea ice cover of the Arctic Ocean and its vicinity. The Arctic ice pack undergoes a regular seasonal cycle in which ice melts in spring and summer, reaches a minimum around mid-September, then increases during fall a ...
decline in the Hudson Strait
Hudson Strait () in Nunavut links the Atlantic Ocean and the Labrador Sea to Hudson Bay in Canada. This strait lies between Baffin Island and Nunavik, with its eastern entrance marked by Cape Chidley in Newfoundland and Labrador and Nunavut ...
, their range now extends deep into the northwest Atlantic. Occasionally, orcas swim into freshwater rivers. They have been documented up the Columbia River
The Columbia River (Upper Chinook language, Upper Chinook: ' or '; Sahaptin language, Sahaptin: ''Nch’i-Wàna'' or ''Nchi wana''; Sinixt dialect'' '') is the largest river in the Pacific Northwest region of North America. The river headwater ...
in the United States. They have also been found in the Fraser River
The Fraser River () is the longest river within British Columbia, Canada, rising at Fraser Pass near Blackrock Mountain (Canada), Blackrock Mountain in the Rocky Mountains and flowing for , into the Strait of Georgia just south of the City of V ...
in Canada and the Horikawa River
The flows north to south through Nagoya, Aichi Prefecture, Japan, and is part of the Shōnai River
The is a Class 1 river flowing through Gifu and Aichi prefectures in Japan. In Gifu Prefecture, it is also referred to as the Toki River ( ...
in Japan.
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.
Population
Worldwide population estimates are uncertain, but recent consensus suggests a minimum of 50,000 (2006). 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. Japan's Fisheries Agency estimated in the 2000s that 2,321 orcas were in the seas around Japan.Feeding
Orcas areapex predator
An apex predator, also known as a top predator or superpredator, is a predator at the top of a food chain, without natural predators of its own.
Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the hig ...
s, meaning that they themselves have no natural predators. They are sometimes called "wolves of the sea", because they hunt in groups like wolf packs. Orcas hunt varied prey including fish, cephalopod
A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
s, mammals, seabird
Seabirds (also known as marine birds) are birds that are adaptation, adapted to life within the marine ecosystem, marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent ...
s, and sea turtles
Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leatherback, loggerh ...
. Different populations or ecotypes may specialize, and some can have a dramatic impact on prey species. However, whales in tropical areas appear to have more generalized diets due to lower food productivity. Orcas spend most of their time at shallow depths, but occasionally dive several hundred metres depending on their prey.
Fish
Fish-eating orcas prey on around 30 species of fish. Some populations in the Norwegian andGreenland
Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...
sea specialize in herring
Herring are various species of forage fish, belonging to the Order (biology), order Clupeiformes.
Herring often move in large Shoaling and schooling, schools around fishing banks and near the coast, found particularly in shallow, temperate wate ...
and follow that fish's autumnal migration to the Norwegian coast. Salmon
Salmon (; : salmon) are any of several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the genera ''Salmo'' and ''Oncorhynchus'' of the family (biology), family Salmonidae, native ...
account for 96% of northeast Pacific residents' diet, particularly Chinook salmon which make up 65% of the salmon eaten by orcas. Chum salmon
The chum salmon (''Oncorhynchus keta''), also known as dog salmon or keta salmon, is a species of anadromous salmonid fish from the genus ''Oncorhynchus'' (Pacific salmon) native to the coastal rivers of the North Pacific and the Beringian Arctic ...
are also eaten, but smaller sockeye
The sockeye salmon (''Oncorhynchus nerka''), also called red salmon, kokanee salmon, blueback salmon, or simply sockeye, is an anadromous species of salmon found in the Pacific Ocean, Northern Pacific Ocean and rivers discharging into it. This ...
and pink salmon
Pink salmon or humpback salmon (''Oncorhynchus gorbuscha'') is a species of euryhaline ray-finned fish in the family Salmonidae. It is the type species of the genus ''Oncorhynchus'' (Pacific salmon), and is the smallest and most abundant of t ...
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. On average, an orca eats each day. While salmon are usually hunted by an individual whale or a small group, herring are often caught using carousel feeding
A carousel or carrousel (mainly North American English), merry-go-round ( International English), or galloper (British English) is a type of amusement ride consisting of a rotating circular platform with seats for riders. The seats are tradi ...
: the orcas 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 been documented only in the Norwegian orca population, as well as some oceanic dolphin species.
In New Zealand, shark
Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...
s and rays
Ray or RAY may refer to:
Fish
* Ray (fish), any cartilaginous fish of the superorder Batoidea
* Ray (fish fin anatomy), the bony or horny spine on ray-finned fish
Science and mathematics
* Half-line (geometry) or ray, half of a line split at an ...
appear to be important prey, including eagle ray
The eagle rays are a group of cartilaginous fishes in the family Myliobatidae, consisting mostly of large species living in the open ocean rather than on the sea bottom.
Eagle rays feed on mollusks, and crustaceans, crushing their shells with th ...
s, long-tail
In statistics and business, a long tail of some distributions of numbers is the portion of the distribution having many occurrences far from the "head" or central part of the distribution. The distribution could involve popularities, random n ...
and short-tail stingrays, common thresher
The common thresher (''Alopias vulpinus''), also known as Atlantic thresher, is the largest species of thresher shark, family (biology), family Alopiidae, reaching some in length. About half of its length consists of the elongated upper lobe of ...
s, smooth hammerhead
The smooth hammerhead (''Sphyrna zygaena'') is a species of hammerhead shark, and part of the family Sphyrnidae. This species is named "smooth hammerhead" because of the distinctive shape of the head, which is flattened and laterally extended in ...
s, blue shark
The blue shark (''Prionace glauca''), also known as the great blue shark, is a species of requiem shark, in the family Carcharhinidae and the only member of its genus which inhabits deep waters in the world's temperate and tropical oceans. Ave ...
s, basking sharks
The basking shark (''Cetorhinus maximus'') is the second-largest living shark and fish, after the whale shark. It is one of three plankton-eating shark species, along with the whale shark and megamouth shark. Typically, basking sharks reach ...
, and shortfin makos. With sharks, orcas may herd them to the surface and strike them with their tail flukes, while bottom-dwelling rays are cornered, pinned to the ground and taken to the surface. In other parts of the world, orcas have preyed on broadnose sevengill shark
The broadnose sevengill shark (''Notorynchus cepedianus'') is the only extant member of the genus ''Notorynchus'', in the family Hexanchidae. It is recognizable because of its seven gill slits, while most shark species have five gill slits, with ...
s, whale shark
The whale shark (''Rhincodon typus'') is a slow-moving, filter feeder, filter-feeding carpet shark and the largest known Extant taxon, extant fish species. The largest confirmed individual had a length of . The whale shark holds many records for ...
s, and even great white shark
The great white shark (''Carcharodon carcharias''), also known as the white shark, white pointer, or simply great white, is a species of large Lamniformes, mackerel shark which can be found in the coastal surface waters of all the major ocea ...
s. Competition between orcas and white sharks is probable in regions where their diets overlap. The arrival of orcas in an area can cause white sharks to flee and forage elsewhere. Orcas appear to target the liver of sharks. In one case a single orca was observed killing and eating a great white shark on its own.
Mammals and birds
Orcas are sophisticated and effective predators ofmarine mammal
Marine mammals are mammals that rely on marine ecosystems for their existence. They include animals such as cetaceans, pinnipeds, sirenians, sea otters and polar bears. They are an informal group, unified only by their reliance on marine enviro ...
s. They are recorded to prey on other cetacean species, usually smaller dolphins and porpoise
Porpoises () are small Oceanic dolphin, dolphin-like cetaceans classified under the family Phocoenidae. Although similar in appearance to dolphins, they are more closely related to narwhals and Beluga whale, belugas than to the Oceanic dolphi ...
s such as common dolphin
The common dolphin (''Delphinus delphis'') is the most abundant cetacean in the world, with a global population of about six million. Despite this fact and its vernacular name, the common dolphin is not thought of as the archetypal dolphin, wit ...
s, bottlenose dolphin
The bottlenose dolphin is a toothed whale in the genus ''Tursiops''. They are common, cosmopolitan members of the family Delphinidae, the family of oceanic dolphins. Molecular studies show the genus contains three species: the common bot ...
s, Pacific white-sided dolphin
The Pacific white-sided dolphin (''Lagenorhynchus obliquidens''), also known as the hookfin porpoise, is an active dolphin found in the cool or temperate waters of the North Pacific Ocean.
Taxonomy
The Pacific white-sided dolphin was named by Sm ...
s, dusky dolphin
The dusky dolphin (''Lagenorhynchus obscurus'') is a small oceanic dolphin found in coastal waters of the Southern Hemisphere. It is most closely related to the Pacific white-sided dolphin. The dolphin's range is patchy, major populations occ ...
s, harbour porpoise
The harbour porpoise (''Phocoena phocoena'') is one of eight extant species of porpoise. It is one of the smallest species of cetacean. As its name implies, it stays close to coastal areas or river estuaries, and as such, is the most familiar ...
s and Dall's porpoise
Dall's porpoise (''Phocoenoides dalli'') is a species of porpoise endemic to the North Pacific. It is the largest of porpoises and the only member of the genus ''Phocoenoides''. The species is named after American naturalist William Healey Dall, ...
s. While hunting these species, orcas usually have to chase them to exhaustion. For highly social species, orca pods try to separate an individual from its group. Larger groups have a better chance of preventing their prey from escaping, which is killed by being thrown around, rammed and jumped on. Arctic orcas may attack beluga whales and narwhal
The narwhal (''Monodon monoceros'') is a species of toothed whale native to the Arctic. It is the only member of the genus ''Monodon'' and one of two living representatives of the family Monodontidae. The narwhal is a stocky cetacean with a ...
s stuck in pools enclosed by sea ice, the former are also driven into shallower water where juveniles are grabbed. By contrast, orcas appear to be wary of pilot whale
Pilot whales are cetaceans belonging to the genus ''Globicephala''. The two Extant taxon, extant species are the long-finned pilot whale (''G. melas'') and the short-finned pilot whale (''G. macrorhynchus''). The two are not readily distinguish ...
s, which have been recorded to mob and chase them. Nevertheless, possible predation on long-finned pilot whales has been recorded in Iceland
Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...
, and one study suggests short-finned pilot whales
The short-finned pilot whale (''Globicephala macrorhynchus'') is one of the two species of cetaceans in the genus '' Globicephala'', which it shares with the long-finned pilot whale (''G. melas''). It is part of the oceanic dolphin family (Delp ...
are among Caribbean Orcas' prey. Killer whales have been recorded attacking short-finned pilot whales in Peru
Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
as well.
Orcas also prey on larger species such as sperm whale
The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the Genus (biology), genus ''Physeter'' and one of three extant species in the s ...
s, grey whale
The gray whale (''Eschrichtius robustus''), also known as the grey whale,Britannica Micro.: v. IV, p. 693. is a baleen whale that migrates between feeding and breeding grounds yearly. It reaches a length of , a weight of up to and lives between ...
s, humpback whale
The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the monotypic taxon, only species in the genus ''Megaptera''. Adults range in length from and weigh u ...
s and minke whales
The minke whale (), or lesser rorqual, is a species complex of baleen whale. The two species of minke whale are the common (or northern) minke whale and the Antarctic (or southern) minke whale. The minke whale was first described by the Danish na ...
. On three separate occasions in 2019 orcas were recorded to have killed blue whale
The blue whale (''Balaenoptera musculus'') is a marine mammal and a baleen whale. Reaching a maximum confirmed length of and weighing up to , it is the largest animal known ever to have existed. The blue whale's long and slender body can ...
s off the south coast of Western Australia, including an estimated individual. Large whales require much effort and coordination to kill and orcas often target calves. A hunt begins with a chase followed by a violent attack on the exhausted prey. Large whales often show signs of orca attack via tooth rake marks. 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. There is also evidence that humpback whales will defend against or mob orcas who are attacking either humpback calves or juveniles as well as members of other species.
History of whaling, Prior to the advent of industrial whaling, great whales may have been the major food source for orcas. The introduction of modern whaling techniques may have aided orcas by the sound of Harpoon cannon, 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 orcas, and caused them to expand their consumption of smaller marine mammals, thus contributing to the decline of these as well.
Other marine mammal prey includes pinniped, seal species such as harbour seals, elephant seals, California sea lions, Steller sea lions, South American sea lions and walruses. Often, to avoid injury, orcas 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. In steeply banked beaches off Península Valdés, Argentina, and the Crozet Islands
The Crozet Islands (; or, officially, ''Archipel Crozet'') are a sub-Antarctic archipelago of small islands in the southern Indian Ocean. They form one of the five administrative districts of the French Southern and Antarctic Lands.
History ...
, orcas feed on South American sea lions and southern elephant seals in shallow water, even beached whale, 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. Orcas can then release the animal near juvenile whales, allowing the younger whales to practice the difficult capture technique on the now-weakened prey. In the Antarctic, type B orcas hunt Weddell seals and other prey by "wave-hunting". They Cetacean surfacing behaviour#Spyhopping, "spy-hop" to locate them 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 orcas lie in wait.
In the Aleutian Islands
The Aleutian Islands ( ; ; , "land of the Aleuts"; possibly from the Chukchi language, Chukchi ''aliat'', or "island")—also called the Aleut Islands, Aleutic Islands, or, before Alaska Purchase, 1867, the Catherine Archipelago—are a chain ...
, a decline in sea otter populations in the 1990s was controversially attributed by some scientists to orca predation, although with no direct evidence. The decline of sea otters followed a decline in seal populations, which in turn may be substitutes for their original prey, now decimated by industrial whaling. Orcas have been observed preying on Terrestrial animal, terrestrial mammals, such as moose swimming between islands off the northwest coast of North America. Orca cannibalism (zoology), 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. One orca was also attacked by its companions after being shot. Although resident orcas have never been observed to eat other marine mammals, they occasionally harass and kill porpoises and seals for no apparent reason. Some dolphins recognize resident orcas as harmless and remain in the same area.
Orcas do consume seabird
Seabirds (also known as marine birds) are birds that are adaptation, adapted to life within the marine ecosystem, marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent ...
s but are more likely to kill and leave them uneaten. Penguin species recorded as prey in Antarctic and sub-Antarctic waters include gentoo penguins, chinstrap penguins, king penguins and rockhopper penguins. Orcas in many areas may prey on cormorants and gulls. A captive orca 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.
Behaviour
Day-to-day orca behaviour generally consists of foraging, travelling, resting and socializing. Orcas frequently engage in Whale surfacing behavior, 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 (animal behavior), play. Spyhopping is a behaviour in which a whale holds its head above water to view its surroundings. Resident orcas swim alongside porpoise
Porpoises () are small Oceanic dolphin, dolphin-like cetaceans classified under the family Phocoenidae. Although similar in appearance to dolphins, they are more closely related to narwhals and Beluga whale, belugas than to the Oceanic dolphi ...
s and other dolphins.
Orcas will engage in surplus killing, that is, killing that is not designed to be for food. As an example, a BBC film crew witnessed orca in British Columbia
British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
playing with a male Steller sea lion to exhaustion, but not eating it.
Some orcas have been observed swimming with dead Salmon hat, salmon on their heads, resembling hats.
Social structure
Orcas have complex societies. Only elephants and higher primates live in comparably complex social structures. Due to orcas' complex social bonds, many marine experts have concerns about how humane it is to keep Captive killer whales, them in captivity. Resident orcas 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. 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. The permanent separation of an individual from a resident matriline has only been recorded once, in the case of an orca named Luna (orca), Luna. 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. DNA testing indicates resident males nearly always mate with females from other pods. 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. The highest association layer is the community, which consists of pods that regularly associate with each other but share no maternal relations or dialects. 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. As in resident clans, transient community members share an acoustic repertoire, although regional differences in vocalizations have been noted. As with residents and transients, the lifestyle of these whales appears to reflect their diet; fish-eating orcas off Norway have resident-like social structures, while mammal-eating orcas in Argentina and theCrozet Islands
The Crozet Islands (; or, officially, ''Archipel Crozet'') are a sub-Antarctic archipelago of small islands in the southern Indian Ocean. They form one of the five administrative districts of the French Southern and Antarctic Lands.
History ...
behave more like transients.
Orcas of the same sex and age group may engage in physical contact and synchronous surfacing. These behaviours do not occur randomly among individuals in a pod, providing evidence of "friendships".
Vocalizations
marine mammal
Marine mammals are mammals that rely on marine ecosystems for their existence. They include animals such as cetaceans, pinnipeds, sirenians, sea otters and polar bears. They are an informal group, unified only by their reliance on marine enviro ...
prey of transients hear whale calls well and thus transients are typically silent. Vocal behaviour in these whales is mainly limited to surfacing activities and milling (slow swimming with no apparent direction) after a kill.
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. Call patterns and structure are distinctive within matrilines. Newborns produce calls similar to their mothers, but have a more limited repertoire. Individuals likely learn their dialect through contact with pod members. Family-specific calls have been observed more frequently in the days following a calf's birth, which may help the calf learn them. 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. 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.
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 orcas have group-specific dialects unlike those of residents and transients.
Norwegian and Icelandic herring
Herring are various species of forage fish, belonging to the Order (biology), order Clupeiformes.
Herring often move in large Shoaling and schooling, schools around fishing banks and near the coast, found particularly in shallow, temperate wate ...
-eating orcas appear to have different vocalizations for activities like hunting. A population that live in McMurdo Sound, Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...
have 28 complex burst-pulse and whistle calls.
Intelligence
Orcas have the second-heaviest brains among marine mammals (aftersperm whale
The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the Genus (biology), genus ''Physeter'' and one of three extant species in the s ...
s, which have the largest brain of any animal). Orcas have more grey matter, gray matter and more cortical neurons than any mammal, including humans. They can be Animal training, trained in captivity and are often described as intelligent, although defining and measuring "intelligence" is difficult in a species whose environment and behavioural strategies are very different from those of humans. Orcas imitate others, and seem to deliberately teach skills to their kin. Off the Crozet Islands
The Crozet Islands (; or, officially, ''Archipel Crozet'') are a sub-Antarctic archipelago of small islands in the southern Indian Ocean. They form one of the five administrative districts of the French Southern and Antarctic Lands.
History ...
, mothers push their calves onto the beach, waiting to pull the youngster back if needed. In March 2023, a female orca was spotted with a newborn pilot whale
Pilot whales are cetaceans belonging to the genus ''Globicephala''. The two Extant taxon, extant species are the long-finned pilot whale (''G. melas'') and the short-finned pilot whale (''G. macrorhynchus''). The two are not readily distinguish ...
in Snæfellsnes.
People who have interacted closely with orcas offer numerous Anecdotal evidence, anecdotes demonstrating the whales' curiosity, playfulness, and ability to solve problems. Alaskan orcas have not only learned how to steal fish from Longline fishing, longlines, but have also overcome a variety of techniques designed to stop them, such as the use of unbaited lines as decoys. 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. The tactic worked initially, but the orcas adapted quickly and split into groups.
In other anecdotes, researchers describe incidents in which wild orcas playfully tease humans by repeatedly moving objects the humans are trying to reach, or suddenly start to toss around a chunk of ice after a human throws a snowball.
The orca's use of dialects and the passing of other learned behaviours from generation to generation have been described as a form of animal culture
Animal culture can be defined as the ability of non-human animals to learn and transmit behaviors through processes of social or cultural learning.
Culture is increasingly seen as a process, involving the social transmittance of behavior among p ...
.
Life cycle
Female orcas begin to mature at around the age of 10–13 and reach peak fertility around 20, 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. Orcas are among the few Menopause#Other animals, animals that undergo menopause and live for decades after they have finished breeding. The lifespans of wild females average 50 to 80 years. Some are claimed to have lived substantially longer: Granny (orca), 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. 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. Males mate with females from other pods, which prevents inbreeding. Gestation period, Gestation varies from 15 to 18 months. 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. 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. 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. One male, known as Old Tom (killer whale), 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, but this method of age determination is now believed to be inaccurate for older animals. 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. Orcas are unique among cetaceans, as their caudal sections elongate with age, making their heads relatively shorter. Infanticide (zoology), Infanticide, once thought to occur only in captive orcas, 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 Infanticide in carnivores, 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 thebottlenose dolphin
The bottlenose dolphin is a toothed whale in the genus ''Tursiops''. They are common, cosmopolitan members of the family Delphinidae, the family of oceanic dolphins. Molecular studies show the genus contains three species: the common bot ...
.
Conservation
In 2008, the IUCN
The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
(International Union for Conservation of Nature) changed its assessment of the orca's conservation status
The conservation status of a group of organisms (for instance, a species) indicates whether the group still exists and how likely the group is to become extinct in the near future. Many factors are taken into account when assessing conservation ...
from conservation dependent to data deficient
A data deficient (DD) species is one which has been categorized by the International Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment of conservation status to be made. This does not necessaril ...
, recognizing that one or more orca types may actually be separate, endangered species. overfishing, Depletion of prey species, Marine pollution, pollution, large-scale oil spills, and Disturbance (ecology), habitat disturbance caused by noise and conflicts with boats are the most significant worldwide threats. In January 2020, the first orca in England and Wales since 2001 was found dead with a large fragment of plastic in its stomach.
Like other animals at the highest trophic levels, the orca is particularly at risk of poisoning from bioaccumulation of toxins, including Polychlorinated biphenyls (PCBs). 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
Washington most commonly refers to:
* George Washington (1732–1799), the first president of the United States
* Washington (state), a state in the Pacific Northwest of the United States
* Washington, D.C., the capital of the United States
** A ...
coast found PCB levels in orcas were higher than levels that had caused health problems in harbour seals. Blubber samples in the Arctic Norway, Norwegian Arctic show higher levels of PCBs, pesticides and brominated flame-retardants than in polar bears. A 2018 study published in ''Science (journal), Science'' found that global orca populations are poised to dramatically decline due such toxic pollution.
In the Pacific Northwest, wild salmon stocks, a main resident food source, have declined dramatically in recent years. In the Puget Sound region, only 75 whales remain with few births over the last few years. On the west coast of Alaska and the Aleutian Islands
The Aleutian Islands ( ; ; , "land of the Aleuts"; possibly from the Chukchi language, Chukchi ''aliat'', or "island")—also called the Aleut Islands, Aleutic Islands, or, before Alaska Purchase, 1867, the Catherine Archipelago—are a chain ...
, seal and sea lion populations have also substantially declined.
In 2005, the United States government listed the southern resident killer whales, southern resident community as an endangered population under the Endangered Species Act. This community comprises three pods which live mostly in the Strait of Georgia, Georgia and Haro Straits and Puget Sound in British Columbia
British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
and Washington. They do not breed outside of their community, which was once estimated at 200 animals and later shrank to around 90. In October 2008, the annual survey revealed seven were missing and presumed dead, reducing the count to 83. This is potentially the largest decline in the population in the past 10 years. These deaths can be attributed to declines in Chinook salmon.Le PhuongResearchers: 7 Orcas Missing from Puget Sound
, Associated Press. USA Today, October 25, 2008 Scientist Ken Balcomb has extensively studied orcas since 1976; he is the research biologist responsible for discovering Marine mammals and sonar#Naval sonar-linked incidents, U.S. Navy sonar may harm orcas. He studied orcas from the Center for Whale Research, located in Friday Harbor, Washington, Friday Harbor, Washington. He was also able to study orcas from "his home porch perched above Puget Sound, where the animals hunt and play in summer months". In May 2003, Balcomb (along with other whale watching, whale watchers near the Puget Sound coastline) noticed uncharacteristic behaviour displayed by the orcas. The whales seemed "agitated and were moving haphazardly, attempting to lift their heads free of the water" to escape the sound of the sonars. "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 distant, Balcomb said." The impact of sonar waves on orcas 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. 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. 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 orcas aside from the laws already in place. In response to this decision, six environmental groups sued the federal government, claiming orcas were facing threats along the British Columbia Coast including increased boat traffic, water toxic wastes, and low salmon population, and the federal government did nothing to protect them. Underwater acoustics, Underwater noise from shipping, drilling, and other human activities is a significant concern in some key orca habitats, including Johnstone Strait and Haro Strait. In the mid-1990s, loud underwater noises from salmon farms were used to deter seals. Orcas also avoided the surrounding waters. High-intensity sonar used by the United States Navy, Navy disturbs orcas along with other marine mammals. Orcas are popular with whale watching, whale watchers, which may stress the whales and alter their behaviour, particularly if boats approach too closely or block their lines of travel. The Exxon Valdez oil spill, ''Exxon Valdez'' oil spill adversely affected orcas 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 orcas. 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. Orcas are included in Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning international trade (including in parts/derivatives) is regulated.
Relationship with humans
Indigenous cultures
The Indigenous peoples of the Pacific Northwest Coast feature orcas throughout Northwest Coast art, their art, history, spirituality and religion. The Haida people, Haida regarded orcas as the most powerful animals in the ocean, and their mythology tells of orcas living in houses and towns under the sea. According to these stories, they took on human form when submerged, and humans who drowned went to live with them. For the Kwakwaka'wakw, the orca was regarded as the ruler of the undersea world, with sea lions for slaves and dolphins for warriors. In Nuu-chah-nulth people, Nuu-chah-nulth and Kwakwaka'wakw mythology, orcas may embody the souls of deceased chiefs. The Tlingit people, Tlingit of southeastern Alaska regarded the orca as custodian of the sea and a benefactor of humans. The Lummi people, Lummi consider orca to be people, referring to them as "qwe'lhol'mechen" which means "our relations under the waves". The Maritime Archaic people of Newfoundland (island), Newfoundland also had great respect for orcas, as evidenced by stone carvings found in a 4,000-year-old burial at the Port au Choix Archaeological Site. In the tales and beliefs of the Siberian Yupik people, orcas are said to appear as Wolf, wolves in winter, and wolves as orcas in summer.''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: Russian Academy of Sciences, Academy of Sciences of the USSR. Original data: Е.С. Рубцова: Материалы по языку и фольклору эскимосов (чаплинский диалект). Академия Наук СССР. Москва-Ленинград, 1954Menovshchikov, G. A. (1962). ''Grammar of the language of Asian Eskimos''. Vol. I., pp. 439, 441. Moscow and Leningrad: Russian Academy of Sciences, Academy of Sciences of the USSR. Original data: Г. А. Меновщиков: Грамматиκа языка азиатских эскимосов. Часть первая. Академия Наук СССР. Москва-Ленинград, 1962 Orcas are believed to assist their hunters in driving walrus. A radio interview with Russian scientists about man and animal, examples taken especially from Asian Eskimos Reverence is expressed in several forms: the boat represents the animal, and a wooden carving hung from the hunter's belt. Small sacrifices such as tobacco or meat are strewn into the sea for them. The Ainu people of Hokkaido, the Kuril Islands, and southern Sakhalin often referred to orcas 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.Attacks by wild orcas on humans and animals
In Western cultures, orcas were historically feared as dangerous, savage predators. The first written description of an orca 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." (see citation in section #Naming, "Naming", above).Pliny the Elder, Gaius Plinius Secundus''Historia Naturalis'' 9.5.12
(Latin), in Bill Thayer's
''. (See also a
English translation
by John Bostock (physician), John Bostock and Henry Thomas Riley, 1855.) Retrieved February 19, 2010. Of the very few confirmed attacks on humans by wild orcas, none have been fatal. In one instance, orcas tried to tip ice floes on which a dog team and Herbert Ponting, photographer of the Terra Nova Expedition were standing. The sled dogs' barking is speculated to have sounded enough like seal calls to trigger the orca's hunting curiosity. In the 1970s, a surfer in California was bitten, but the Orca then retreated, and in 2005, a boy in Alaska who was splashing in a region frequented by harbour seals was bumped by an orca that apparently misidentified him as prey.
Orca attacks on sailboats and small vessels
Beginning around 2020, one or more pods of orcas began to attack sailing vessels off the southern tip of Europe, and a few were sunk. At least 15 interactions between orcas and boats off the Iberian coast were reported in 2020. According to the Atlantic Orca Working Group (GTOA) as many as 500 vessels have been damaged between 2020 and 2023. In one video, an orca can be seen biting on one of the two rudders ripped from a catamaran near Gibraltar. The captain of the vessel reported this was the second attack on a vessel under his command and the orcas focused on the rudders. "Looks like they knew exactly what they are doing. They didn't touch anything else." After an orca repeatedly rammed a vessel off the coast of Norway in 2023, there is a concern the behavior is spreading to other areas. This has led to recommendations that sailors now carry bags of sand. Dropping sand into the water near the rudder is thought to confuse the sonar signal. Experts were divided as to whether the behavior was some sort of revenge or protection response to a previous traumatic incident, or playful or frustrated attempts to get a boat's propeller to emit a stream of high-speed water.Attacks on humans by captive orcas
Unlike wild orcas, captive orcas have made nearly two dozen Killer whale attacks on humans, attacks on humans since the 1970s, some of which have been fatal.Human attacks on orcas
Competition with fishermen also led to orcas being regarded as pests. In the waters of the Pacific Northwest andIceland
Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...
, the shooting of orcas was accepted and even encouraged by governments. As an indication of the intensity of shooting that occurred until fairly recently, about 25% of the orcas captured in Puget Sound for aquariums through 1970 bore bullet scars. The U.S. Navy claimed to have deliberately killed hundreds of orcas in Icelandic waters in 1956 with machine guns, rockets, and depth charges.
Modern Western attitudes
Western attitudes towards orcas have changed dramatically in recent decades. In the mid-1960s and early 1970s, orcas came to much greater public and scientific awareness, starting with the live-capture and display of an orca known as Moby Doll, a southern resident orca harpooned off Saturna Island in 1964. He was the first ever orca to be studied at close quarters alive, not postmortem. Moby Doll's impact in scientific research at the time, including the first scientific studies of an orca's sound production, led to two articles about him in the journal ''Zoologica''. 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.
Between 1964 and 1976, 50 orcas from the Pacific Northwest were captured for display in Aquarium, 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 Wildlife photo-identification, photo-identification techniques, individuals were named and tracked over decades.
Bigg's techniques also revealed the Pacific Northwest population was in the low hundreds rather than the thousands that had been previously assumed. The southern resident community alone had lost 48 of its members to captivity; by 1976, only 80 remained. In the Pacific Northwest, the species that had unthinkingly been targeted became a cultural icon within a few decades.
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 orcas 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 (whale), Keiko was returned to the coast of his native Iceland
Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...
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. Keiko however did not adapt to the harsh climate of the Arctic Ocean, and died a year into his release after contracting Pneumonia (non-human), pneumonia, at the age of 27. In 2002, the orphan Springer (orca), 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 orcas. The saving of Springer raised hopes that another young orca named Luna (killer whale), 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.
Whaling
The earliest known records of commercial hunting of orcas date to the 18th century in Japan. During the 19th and early 20th centuries, the global whaling industry caught immense numbers of Baleen whale, baleen and sperm whales, but largely ignored orcas because of their limited amounts of Whale oil, recoverable oil, their smaller populations, and the difficulty of taking them. Once the stocks of larger species were depleted, orcas were targeted by commercial whalers in the mid-20th century. Between 1954 and 1997, Japan took 1,178 orcas (although the Ministry of the Environment (Japan), Ministry of the Environment claims that there had been domestic catches of about 1,600 whales between late 1940s to 1960s) and Norway took 987. Extensive hunting of orcas, including anAntarctic
The Antarctic (, ; commonly ) is the polar regions of Earth, polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is antipodes, diametrically opposite of the Arctic region around the North Pole.
The Antar ...
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. Today, no country carries out a substantial hunt, although Indonesia and Greenland
Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...
permit small subsistence hunts (see Aboriginal whaling). Other than commercial hunts, orcas 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, the killing of five whales from a pod of 11 members that swam into Tokyo Bay in 1970, and a catch record in southern Taiwan in the 1990s.
Cooperation with humans
Orcas have helped humans hunting other whales. One well-known example was the Killer whales of Eden, New South Wales, orcas of Eden, Australia, including the male known as Old Tom (orca), Old Tom. Whalers more often considered them a nuisance, however, as orcas would gather to scavenge meat from the whalers' catch. Some populations, such as in Alaska's Prince William Sound, may have been reduced significantly by whalers shooting them in retaliation.Whale watching
Whale watching continues to increase in popularity, but may have some problematic impacts on orcas. Exposure to exhaust gases from large amounts of vessel traffic is causing concern for the overall health of the 75 remaining southern resident orcas (SRKWs) left as of early 2019. This population is followed by approximately 20 vessels for 12 hours a day during the months May–September. Researchers discovered that these vessels are in the line of sight for these whales for 98–99.5% of daylight hours. 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. 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. 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.Captivity
The orca's Animal intelligence, intelligence, trainability, striking appearance, playfulness in captivity and sheer size have made it a popular exhibit at aquaria and Marine mammal park, 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.
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. 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 orcas. 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. 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 orca behaviour, see #Behaviour, above. Wild orcas may travel up to in a day, and critics say the animals are too big and intelligent to be suitable for captivity.Associated PressWhale Attack Renews Captive Animal Debate
''CBS News'', March 1, 2010. Retrieved March 7, 2010 Captives occasionally act aggressively towards themselves, their tankmates, or humans, which critics say is a result of stress (medicine), stress. Between 1991 and 2010, the bull orca known as Tilikum (orca), Tilikum was involved in the death of three people, and was featured in the critically acclaimed 2013 film Blackfish (film), ''Blackfish''. Tilikum lived at SeaWorld from 1992 until his death in 2017. In March 2016, SeaWorld announced that they would be ending their orca breeding program and their theatrical shows. However, as of 2020, theatrical shows featuring orcas are still ongoing.
See also
*List of marine mammal species **List of cetaceans ***''Livyatan melvillei'' – occupied a similar ecological niche *Ingrid Visser (researcher) – a New Zealand biologist who swims with wild orcasFootnotes
References
Works cited
* * * * * * * * * *Further reading
* * *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
, HowStuffWorks.com, article by Jacob Silverman
Orca devours great white shark
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 {{Featured article Orcas, Cosmopolitan mammals Animals that use echolocation Mammals described in 1758 Articles containing video clips Taxa named by Carl Linnaeus