Some local populations are considered threatened or endangered due to prey depletion, habitat loss, pollution (by PCBs), capture for marine mammal parks, and conflicts with human fisheries.

orcae) for these animals, possibly borrowing Ancient Greek ὄρυξ (óryx), which referred (among other things) to a whale species, perhaps a narwhal.

[15] Konrad Gessner wrote the first scientific description of an orca in his Piscium & aquatilium animantium natura of 1558, part of the larger Historia animalium, based on examination of a dead stranded animal in the Bay of Greifswald that had attracted a great deal of local interest.

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 orca groups complicate simple differentiation into types,[23] research off the west coast of North America has identified fish-eating "residents", mammal-eating "transients" and "offshores".

[26][27] A 2024 study supported the elevation of Eastern North American resident and transient orcas as distinct species, O. ater and O. rectipinnus respectively.

[22] 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.

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.

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,[45] as do other members of the dolphin family.

Due to their enormous range, numbers, and density, relative distribution is difficult to estimate,[50] but they clearly prefer higher latitudes and coastal areas over pelagic environments.

They are considered "common" (0.20–0.40 individuals per 100 km2) in the eastern Pacific along the coasts of British Columbia, Washington and Oregon, in the North Atlantic Ocean around Iceland and the Faroe Islands.

Arctic orcas may attack beluga whales and narwhals stuck in pools enclosed by sea ice, the former are also driven into shallower water where juveniles are grabbed.

[84][40] On three separate occasions in 2019 orcas were recorded to have killed blue whales off the south coast of Western Australia, including an estimated 18–22-meter (59–72 ft) individual.

[25] Although resident orcas have never been observed to eat other marine mammals, they occasionally harass and kill porpoises and seals for no apparent reason.

As an example, a BBC film crew witnessed orca in British Columbia playing with a male Steller sea lion to exhaustion, but not eating it.

Unlike residents, extended or permanent separation of transient offspring from natal matrilines is common, with juveniles and adults of both sexes participating.

All members of the North American west coast transient community express the same basic dialect, although minor regional variation in call types is evident.

[139] People who have interacted closely with orcas offer numerous anecdotes demonstrating the whales' curiosity, playfulness, and ability to solve problems.

Alaskan orcas 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.

[3] Depletion of prey species, pollution, large-scale oil spills, and habitat disturbance caused by noise and conflicts with boats are the most significant worldwide threats.

[173] The Exxon Valdez oil spill adversely affected orcas in Prince William Sound and Alaska's Kenai Fjords region.

[178] The Maritime Archaic people of 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.

[198] 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.

[187] 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.

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.

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.

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.

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.

[224] The orca's intelligence, trainability, striking appearance, playfulness in captivity and sheer size have made it a popular exhibit at aquaria and aquatic theme parks.

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 above.