Killer whale

Although the term "orca" is increasingly used, English-speaking scientists most often use the traditional name "killer whale".[11] The genus name Orcinus means "of the kingdom of the dead",[12] or "belonging to Orcus".[13] Ancient Romans originally used orca (pl. orcae) for these animals, possibly borrowing Ancient Greek ὄρυξ (óryx), which referred (among other things) to a whale species. Since the 1960s, "orca" has steadily grown in common use.[11] As part of the family Delphinidae, the species is more closely related to other oceanic dolphins than to other whales.[14]

They are sometimes referred to as "blackfish", a name also used for other whale species. "Grampus" is a former name for the species, but is now seldom used. This meaning of "grampus" should not be confused with the genus Grampus, whose only member is Risso's dolphin.[15]

The three to five types of killer whales may be distinct enough to be considered different races,[16] subspecies, or possibly even species[17] (see Species problem). The IUCN reported in 2008, "The taxonomy 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."[3] Although large variation in the ecological distinctiveness of different killer whale groups complicate simple differentiation into types,[18] research off the west coast of Canada and the United States in the 1970s and 1980s identified the following three types:

• Resident: These are the most commonly sighted of the three populations in the coastal waters of the northeast Pacific. Residents' diets consist primarily of fish[19] and sometimes squid, and they live in complex and cohesive family groups called pods.[20] Female residents characteristically have rounded dorsal fin tips that terminate in a sharp corner.[21] They visit the same areas consistently. British Columbia and Washington resident populations are amongst the most intensively studied marine mammals anywhere in the world. Researchers have identified and named over 300 killer whales over the past 30 years.[22]
• Transient: The diets of these whales consist almost exclusively of marine mammals.[19][21] Transients generally travel in small groups, usually of two to six animals, and have less persistent family bonds than residents.[23] Transients vocalize in less variable and less complex dialects.[24] Female transients are characterized by more triangular and pointed dorsal fins than those of residents.[21] The grey or white area around the dorsal fin, known as the "saddle patch", often contains some black colouring in residents. However, the saddle patches of transients are solid and uniformly grey.[21] Transients roam widely along the coast; some individuals have been sighted in both southern Alaska and California.[25] Transients are also referred to as Bigg's killer whale in honour of cetologist Michael Bigg. The term has become increasingly common and may eventually replace the transient label.[26]
• Offshore: A third population of killer whales in the northeast Pacific was discovered in 1988, when a humpback whale researcher observed them in open water. As their name suggests, they travel far from shore and feed primarily on schooling fish.[27] However, because they have large, scarred and nicked dorsal fins resembling those of mammal-hunting transients, it may be that they also eat mammals and sharks.[28][29] They have mostly been encountered off the west coast of Vancouver Island and near Haida Gwaii. Offshores typically congregate in groups of 20–75, with occasional sightings of larger groups of up to 200.[30] Little is known about their habits, but they are genetically distinct from residents and transients. Offshores appear to be smaller than the others, and females are characterized by dorsal fin tips that are continuously rounded.[21]

Type C killer whales in the Ross Sea in the Southern Ocean: The eye patch slants forward.

Transients and residents live in the same areas, but avoid each other.[31][32][33]

Other populations have not been as well studied, although specialized fish and mammal eating killer whales have been distinguished elsewhere.[34] In addition, separate populations of "generalist" (fish- and mammal-eating) and "specialist" (mammal-eating) killer whales have been identified off northwestern Europe.[35][36] As with residents and transients, the lifestyle of these whales appears to reflect their diet; fish-eating killer whales in Alaska[37] and Norway[38] have resident-like social structures, while mammal-eating killer whales in Argentina and the Crozet Islands behave more like transients.[39]

Three types have been documented in the Antarctic. Two dwarf species, named Orcinus nanus and Orcinus glacialis, were described during the 1980s by Soviet researchers, but most cetacean researchers are sceptical about their status, and linking these directly to the types described below is difficult.[17]

Some examples of variations in killer whales

• Type A looks like a "typical" killer whale, a large, black-and-white form with a medium-sized white eye patch, living in open water and feeding mostly on minke whales.[17]
• Type B is smaller than type A. It has a large white eye patch. Most of the dark parts of its body are medium grey instead of black, although it has a dark grey patch called a "dorsal cape"[40] stretching back from its forehead to just behind its dorsal fin. The white areas are stained slightly yellow. It feeds mostly on seals.[17]
• Type C is the smallest and lives in larger groups than the others. Its eye patch is distinctively slanted forwards, rather than parallel to the body axis. Like type B, it is primarily white and medium grey, with a dark grey dorsal cape and yellow-tinged patches. Its only observed prey is the Antarctic cod.[17]
• Type D was identified based on photographs of a 1955 mass stranding in New Zealand and six at-sea sightings since 2004. The first video record of this type was made in 2014 between the Kerguelen and Crozet Islands,[41] and again in 2017 off the coast of Cape Horn, Chile.[42] It is recognizable by its small white eye patch, narrower and shorter than usual dorsal fin, bulbous head (similar to a pilot whale), and smaller teeth.[43] Its geographic range appears to be circumglobal in sub-Antarctic waters between latitudes 40°S and 60°S. Although its diet is not determined, it likely includes fish, as determined by photographs around longline vessels, where Type D orcas appeared to be preying on Patagonian toothfish (Dissostichus eleginoides).[44][45]

Types B and C live close to the ice pack, and diatoms in these waters may be responsible for the yellowish colouring of both types.[17][46] Mitochondrial DNA sequences support the theory that these are recently diverged separate species.[47] More recently, complete mitochondrial sequencing indicates the two Antarctic groups that eat seals and fish should be recognized as distinct species, as should the North Pacific transients, leaving the others as subspecies pending additional data.[48] Advanced methods that sequenced the entire mitochondrial genome revealed systematic differences in DNA between different populations.[49] A 2019 study of Type D orcas also found them to be distinct from other populations and possibly even a unique species.[44]

Mammal-eating killer whales in different regions were long thought likely to be closely related, but genetic testing has refuted this hypothesis.[50]

There are seven identified ecotypes inhabiting isolated ecological niches. Of three orca ecotypes in the Antarctic, one preys on minke whales, the second on seals and penguins, and the third on fish. Another ecotype lives in the eastern North Atlantic, while the three Northeast Pacific ecotypes are labelled the transient, resident and offshore populations described above. Research has supported a proposal to reclassify the Antarctic seal- and fish-eating populations and the North Pacific transients as a distinct species, leaving the remaining ecotypes as subspecies. The first split in the orca population, between the North Pacific transients and the rest, occurred an estimated 700,000 years ago. Such a designation would mean that each new species becomes subject to separate conservation assessments.[49]

Worldwide population estimates are uncertain, but recent consensus suggests a minimum of 50,000 (2006).[91][3][30] 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.[92] Japan's Fisheries Agency estimated in the 2000s that 2,321 killer whales were in the seas around Japan.[93][94]

Tail-slapping in Vestfjorden, Norway

Resident (fish-eating) killer whales: The curved dorsal fins are typical of resident females.

Comparison of the size of an average orca and an average great white shark

Fish-eating killer whales prey on around 30 species of fish. Some populations in the Norwegian and Greenland sea specialize in herring and follow that fish's autumnal migration to the Norwegian coast. Salmon account for 96% of northeast Pacific residents' diet, including 65% of large, fatty Chinook.[101] Chum salmon are also eaten, but smaller sockeye and pink salmon are not a significant food item. Depletion of specific prey species in an area is, therefore, cause for concern for local populations, despite the high diversity of prey.[91] On average, a killer whale eats 227 kilograms (500 lb) each day.[102] While salmon are usually hunted by an individual whale or a small group, herring are often caught using carousel feeding: the killer whales force the herring into a tight ball by releasing bursts of bubbles or flashing their white undersides. They then slap the ball with their tail flukes, stunning or killing up to 15 fish at a time, then eating them one by one. Carousel feeding has only been documented in the Norwegian killer whale population, as well as some oceanic dolphin species.[103]

In New Zealand, sharks and rays appear to be important prey, including eagle rays, long-tail and short-tail stingrays, common threshers, smooth hammerheads, blue sharks, basking sharks, and shortfin makos.[104][105] With sharks, orcas may herd them to the surface and strike them with their tail flukes,[104] while bottom-dwelling rays are cornered, pinned to the ground and taken to the surface.[106] In other parts of the world, killer whales have preyed on broadnose sevengill sharks,[107] tiger sharks[108] and even small whale sharks.[109] Killer whales have also been recorded attacking and feeding on great white sharks,[28][110][111][112] and appear to target the liver.[28][111] Competition between killer whales and white sharks is probable in regions where their diets overlap.[113] The arrival of orcas in an area can cause white sharks to flee and forage elsewhere.[114]

Feeding on a northern fur seal, Bogoslof Island, Alaska

Killer whales are sophisticated and effective predators of marine mammals. Thirty-two cetacean species have been recorded as prey, from observing orca feeding activity, examining the stomach contents of dead orcas, and seeing scars on the bodies of surviving prey animals. Groups even attack larger cetaceans such as minke whales, grey whales,[115][116] and, rarely, sperm whales or blue whales.[34][117][118][119] Predation by orcas on whale calves in high-productivity, high-latitude areas may account for great whale migrations during breeding season to low-productivity tropical waters where orcas are scarcer.[115][120]

Hunting a large whale usually takes several hours. Killer whales generally attack young or weak animals.[115] When hunting a young whale, a group chases it and its mother to exhaustion. Eventually, they separate the pair and surround the calf, drowning it by keeping it from surfacing, and may consume only its jaw and tongue.[115] 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.[121] Rarely, large killer whale pods can overwhelm even adult female sperm whales. Adult bull sperm whales, which are large, powerful and aggressive when threatened, and fully grown adult blue whales, which are possibly too large to overwhelm, are not believed to be prey for killer whales.[122]

Prior to the advent of industrial whaling, great whales may have been the major food source for killer whales. The introduction of modern whaling techniques may have aided killer whales by the sound of exploding harpoons indicating availability of prey to scavenge, and compressed air inflation of whale carcasses causing them to float, thus exposing them to scavenging. However, the devastation of great whale populations by unfettered whaling has possibly reduced their availability for killer whales, and caused them to expand their consumption of smaller marine mammals, thus contributing to the decline of these as well.[120]

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

Other marine mammal prey species include nearly 20 species of seal, sea lion and fur seal. Walruses and sea otters are less frequently taken. Often, to avoid injury, killer whales disable their prey before killing and eating it. This may involve throwing it in the air, slapping it with their tails, ramming it, or breaching and landing on it.[123] In the Aleutian Islands, a decline in sea otter populations in the 1990s was controversially attributed by some scientists to killer whale predation, although with no direct evidence.[124] The decline of sea otters followed a decline in harbour seal and Steller sea lion populations, the killer whale's preferred prey,[lower-alpha 1][126] which in turn may be substitutes for their original prey, now decimated by industrial whaling.[127][128][129]

In steeply banked beaches off Península Valdés, Argentina, and the Crozet Islands, killer whales feed on South American sea lions and southern elephant seals in shallow water, even beaching temporarily to grab prey before wriggling back to the sea. Beaching, usually fatal to cetaceans, is not an instinctive behaviour, and can require years of practice for the young.[130] Killer whales can then release the animal near juvenile whales, allowing the younger whales to practice the difficult capture technique on the now-weakened prey.[123][131] "Wave-hunting" killer whales "spy-hop" to locate Weddell seals, crabeater seals, leopard seals, and penguins resting on ice floes, and then swim in groups to create waves that wash over the floe. This washes the prey into the water, where other killer whales lie in wait.[49][132][133]

Killer whales have also been observed preying on terrestrial mammals, such as deer swimming between islands off the northwest coast of North America.[125] Killer whale cannibalism has also been reported based on analysis of stomach contents, but this is likely to be the result of scavenging remains dumped by whalers.[134] One killer whale was also attacked by its companions after being shot.[34] Although resident killer whales have never been observed to eat other marine mammals, they occasionally harass and kill porpoises and seals for no apparent reason.[135]

Killer whales in many areas may prey on cormorants and gulls.[136] A captive killer whale at Marineland of Canada discovered it could regurgitate fish onto the surface, attracting sea gulls, and then eat the birds. Four others then learned to copy the behaviour.[137]

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

Killer whales are notable for their complex societies. Only elephants and higher primates live in comparably complex social structures.[140] Due to orcas' complex social bonds, many marine experts have concerns about how humane it is to keep them in captivity.[141]

Resident killer whales in the eastern North Pacific live in particularly complex and stable social groups. Unlike any other known mammal social structure, resident whales live with their mothers for their entire lives. These family groups are based on matrilines consisting of the eldest female (matriarch) and her sons and daughters, and the descendants of her daughters, etc. The average size of a matriline is 5.5 animals.[142] Because females can reach age 90, as many as four generations travel together. These matrilineal groups are highly stable. Individuals separate for only a few hours at a time, to mate or forage. With one exception, a killer whale named Luna, no permanent separation of an individual from a resident matriline has been recorded.[142]

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

Closely related matrilines form loose aggregations called pods, usually consisting of one to four matrilines. Unlike matrilines, pods may separate for weeks or months at a time.[142] DNA testing indicates resident males nearly always mate with females from other pods.[143] 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.[142] The final association layer, perhaps more arbitrarily defined than the familial groupings, is called the community, and is defined as a set of clans that regularly commingle. Clans within a community do not share vocal patterns.[lower-alpha 2]

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.[144] As in resident clans, transient community members share an acoustic repertoire, although regional differences in vocalizations have been noted.[145]

Like all cetaceans, killer whales depend heavily on underwater sound for orientation, feeding, and communication. They produce three categories of sounds: clicks, whistles, and pulsed calls. Clicks are believed to be used primarily for navigation and discriminating prey and other objects in the surrounding environment, but are also commonly heard during social interactions.[30]

Northeast Pacific resident groups tend to be much more vocal than transient groups in the same waters.[146] Residents feed primarily on Chinook and chum, which are insensitive to killer whale calls (inferred from the audiogram of Atlantic salmon). In contrast, the marine mammal prey of transients hear whale calls well. Transients are typically silent.[146] They sometimes use a single click (called a cryptic click) rather than the long train of clicks observed in other populations. Residents are silent only when resting.

All members of a resident pod use similar calls, known collectively as a dialect. Dialects are composed of specific numbers and types of discrete, repetitive calls. They are complex and stable over time.[147] Call patterns and structure are distinctive within matrilines.[148] Newborns produce calls similar to their mothers, but have a more limited repertoire.[145] Individuals likely learn their dialect through contact with pod members.[149] Family-specific calls have been observed more frequently in the days following a calf's birth, which may help the calf learn them.[150] 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.[151] 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.[148]

Dialects also distinguish types. Resident dialects contain seven to 17 (mean = 11) distinctive call types. All members of the North American west coast transient community express the same basic dialect, although minor regional variation in call types is evident. Preliminary research indicates offshore killer whales have group-specific dialects unlike those of residents and transients.[151]

Norwegian and Icelandic herring-eating orcas appear to have different vocalizations for activities like hunting.[152] A population that live in McMurdo Sound, Antarctica have 28 complex burst-pulse and whistle calls.[153]

Killer whales have the second-heaviest brains among marine mammals[154] (after sperm whales, which have the largest brain of any animal).[155] They can be trained in captivity and are often described as intelligent,[156][157] although defining and measuring "intelligence" is difficult in a species whose environment and behavioural strategies are very different from those of humans.[157]

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

Killer whales imitate others, and seem to deliberately teach skills to their kin. Off the Crozet Islands, mothers push their calves onto the beach, waiting to pull the youngster back if needed.[123][131]

People who have interacted closely with killer whales offer numerous anecdotes demonstrating the whales' curiosity, playfulness, and ability to solve problems. Alaskan killer whales have not only learned how to steal fish from longlines, but have also overcome a variety of techniques designed to stop them, such as the use of unbaited lines as decoys.[158] Once, fishermen placed their boats several miles apart, taking turns retrieving small amounts of their catch, in the hope that the whales would not have enough time to move between boats to steal the catch as it was being retrieved. A researcher described what happened next:

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

— Craig Matkin[158]

In other anecdotes, researchers describe incidents in which wild killer whales playfully tease humans by repeatedly moving objects the humans are trying to reach,[159] or suddenly start to toss around a chunk of ice after a human throws a snowball.[160]

The killer whale's use of dialects and the passing of other learned behaviours from generation to generation have been described as a form of animal culture.[161]

The complex and stable vocal and behavioural cultures of sympatric groups of killer whales (Orcinus orca) appear to have no parallel outside humans and represent an independent evolution of cultural faculties.[162]

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

Haida sculpture by Bill Reid

The indigenous peoples of the Pacific Northwest Coast feature killer whales throughout their art, history, spirituality and religion. The Haida regarded killer whales as the most powerful animals in the ocean, and their mythology tells of killer whales living in houses and towns under the sea. According to these myths, they took on human form when submerged, and humans who drowned went to live with them.[193] For the Kwakwaka'wakw, the killer whale was regarded as the ruler of the undersea world, with sea lions for slaves and dolphins for warriors.[193] In Nuu-chah-nulth and Kwakwaka'wakw mythology, killer whales may embody the souls of deceased chiefs.[193] The Tlingit of southeastern Alaska regarded the killer whale as custodian of the sea and a benefactor of humans.[194]

The Maritime Archaic people of Newfoundland also had great respect for killer whales, as evidenced by stone carvings found in a 4,000-year-old burial at the Port au Choix Archaeological Site.[195][196]

In the tales and beliefs of the Siberian Yupik people, killer whales are said to appear as wolves in winter, and wolves as killer whales in summer.[197][198][199][200] Killer whales are believed to assist their hunters in driving walrus.[201] Reverence is expressed in several forms: the boat represents the animal, and a wooden carving hung from the hunter's belt.[199] Small sacrifices such as tobacco or meat are strewn into the sea for them.[201][200]

Indigenous Ainu tribe often referred killer whales in their folklore and myth as Repun Kamuy (God of Sea/Offshore) to bring fortunes (whales) to the coasts, and there had been traditional funerals for stranded or deceased orcas akin to funerals for other animals such as brown bears.[202]

In Western cultures, killer whales were historically feared as dangerous, savage predators.[203] The first written description of a killer whale was given by Pliny the Elder circa AD 70, who wrote, "Orcas (the appearance of which no image can express, other than an enormous mass of savage flesh with teeth) are the enemy of [other kinds of whale]... they charge and pierce them like warships ramming."[204]

Male killer whale depicted in St Mary's in Greifswald, Germany, 1545[7]

Of the very few confirmed attacks on humans by wild killer whales, none have been fatal.[205] In one instance, killer whales tried to tip ice floes on which a dog team and photographer of the Terra Nova Expedition were standing.[206] The sled dogs' barking is speculated to have sounded enough like seal calls to trigger the killer whale's hunting curiosity. In the 1970s, a surfer in California was bitten, and in 2005, a boy in Alaska who was splashing in a region frequented by harbour seals was bumped by a killer whale that apparently misidentified him as prey.[207] Unlike wild killer whales, captive killer whales have made nearly two dozen attacks on humans since the 1970s, some of which have been fatal.[208][209]

Competition with fishermen also led to killer whales being regarded as pests. In the waters of the Pacific Northwest and Iceland, the shooting of killer whales was accepted and even encouraged by governments.[203] As an indication of the intensity of shooting that occurred until fairly recently, about 25% of the killer whales captured in Puget Sound for aquariums through 1970 bore bullet scars.[210] The U.S. Navy claimed to have deliberately killed hundreds of killer whales in Icelandic waters in 1956 with machine guns, rockets, and depth charges.[211][212]

From July to October 2020 there were at least forty reliable reports of orcas attacking boats off the Atlantic coast of Portugal and Spain, unusual and unprecedented behaviour. The nudging, biting and ramming attacks, on medium-size sailing boats sailing at moderate speed, concentrated on the rudder, with some impacts on the hull. A small group of orcas are believed to be responsible, with three juveniles which have been named black Gladis, white Gladis and grey Gladis, identified as present in most attacks. While the incidents were terrifying, no people were injured. The Portuguese coastguard banned small sailing vessels from a region where several incidents had been reported. It is thought that the behaviour is playful, rather than aggressive or vengeful.[213]

Western attitudes towards killer whales have changed dramatically in recent decades. In the mid-1960s and early 1970s, killer whales came to much greater public and scientific awareness, starting with the first live-capture and display of a killer whale known as Moby Doll, a resident harpooned off Saturna Island in 1964.[203] 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.[214]

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

Between 1964 and 1976, 50 killer whales from the Pacific Northwest were captured for display in aquaria, and public interest in the animals grew. In the 1970s, research pioneered by Michael Bigg led to the discovery of the species' complex social structure, its use of vocal communication, and its extraordinarily stable mother–offspring bonds. Through photo-identification techniques, individuals were named and tracked over decades.[215]

Bigg's techniques also revealed the Pacific Northwest population was in the low hundreds rather than the thousands that had been previously assumed.[203] The southern resident community alone had lost 48 of its members to captivity; by 1976, only 80 remained.[216] In the Pacific Northwest, the species that had unthinkingly been targeted became a cultural icon within a few decades.[182]

The public's growing appreciation also led to growing opposition to whale–keeping in aquarium. Only one whale has been taken in North American waters since 1976. In recent years, the extent of the public's interest in killer whales has manifested itself in several high-profile efforts surrounding individuals. Following the success of the 1993 film Free Willy, the movie's captive star Keiko was returned to the coast of his native Iceland in 2002. The director of the International Marine Mammal Project for the Earth Island Institute, David Phillips, led the efforts to return Keiko to the Iceland waters.[217] Keiko however did not adapt to the harsh climate of the Arctic Ocean, and died a year into his release after contracting pneumonia, at the age of 27.[218] In 2002, the orphan Springer was discovered in Puget Sound, Washington. She became the first whale to be successfully reintegrated into a wild pod after human intervention, crystallizing decades of research into the vocal behaviour and social structure of the region's killer whales.[219] The saving of Springer raised hopes that another young killer whale named Luna, which had become separated from his pod, could be returned to it. However, his case was marked by controversy about whether and how to intervene, and in 2006, Luna was killed by a boat propeller.[220]

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

The earlier of known records of commercial hunting of killer whales date to the 18th century in Japan. During the 19th and early 20th centuries, the global whaling industry caught immense numbers of baleen and sperm whales, but largely ignored killer whales because of their limited amounts of recoverable oil, their smaller populations, and the difficulty of taking them.[143] Once the stocks of larger species were depleted, killer whales were targeted by commercial whalers in the mid-20th century. Between 1954 and 1997, Japan took 1,178 killer whales (although the Ministry of the Environment claims that there had been domestic catches of about 1,600 whales between late 1940s to 1960s[221]) and Norway took 987.[222] Extensive hunting of killer whales, including an Antarctic catch of 916 in 1979–80 alone, prompted the International Whaling Commission to recommend a ban on commercial hunting of the species pending further research.[222] Today, no country carries out a substantial hunt, although Indonesia and Greenland permit small subsistence hunts (see Aboriginal whaling). Other than commercial hunts, killer whales were hunted along Japanese coasts out of public concern for potential conflicts with fisheries. Such cases include a semi-resident male-female pair in Akashi Strait and Harimanada being killed in the Seto Inland Sea in 1957,[223][224] the killing of five whales from a pod of 11 members that swam into Tokyo Bay in 1970,[225] and a catch record in southern Taiwan in the 1990s.[79][226]

Killer whales have helped humans hunting other whales.[227] One well-known example was the killer whales of Eden, Australia, including the male known as Old Tom. Whalers more often considered them a nuisance, however, as orcas would gather to scavenge meat from the whalers' catch.[227] Some populations, such as in Alaska's Prince William Sound, may have been reduced significantly by whalers shooting them in retaliation.[16]

Whale watching continues to increase in popularity, but may have some problematic impacts on killer whales. Exposure to exhaust gasses from large amounts of vessel traffic are causing concern for the overall health of the 75 remaining southern resident killer whales (SRKWs) left as of early 2019.[228] This population is followed by approximately 20 vessels for 12 hours a day during the months May–September.[229] Researchers discovered that these vessels are in the line of sight for these whales for 98–99.5% of daylight hours.[229] 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.[229] 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.[229]

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.[230]

Lolita, at the Miami Seaquarium, is one of the oldest whales in captivity.

The killer whale's intelligence, trainability, striking appearance, playfulness in captivity and sheer size have made it a popular exhibit at aquaria and aquatic theme parks. From 1976 to 1997, 55 whales were taken from the wild in Iceland, 19 from Japan, and three from Argentina. These figures exclude animals that died during capture. Live captures fell dramatically in the 1990s, and by 1999, about 40% of the 48 animals on display in the world were captive-born.[231]

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.[lower-alpha 3] That said, a 2015 study coauthored by staff at SeaWorld and the Minnesota Zoo suggested no significant difference in survivorship between free-ranging and captive killer whales.[232] 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.[233] Captivity usually bears little resemblance to wild habitat, and captive whales' social groups are foreign to those found in the wild. Critics claim captive life is stressful due to these factors and the requirement to perform circus tricks that are not part of wild killer whale behaviour, see above.[234] Wild killer whales may travel up to 160 kilometres (100 mi) in a day, and critics say the animals are too big and intelligent to be suitable for captivity.[156] Captives occasionally act aggressively towards themselves, their tankmates, or humans, which critics say is a result of stress.[208] Between 1991 and 2010, the bull orca known as Tilikum was involved in the death of three people, and was featured in the critically acclaimed 2013 film Blackfish.[235] Tilikum lived at SeaWorld from 1992 until his death in 2017.[236][237][238][239][240]

In March 2016, SeaWorld announced that they would be ending their orca breeding program and their theatrical shows.[241] As of 2020, theatrical shows featuring orcas are still ongoing.[242]