Killer whales are dolphins that hunt like wolf packs
Orcas (Orcinus orca), also called killer whales, are the largest oceanic dolphins and the only living Orcinus species. Apex hunters, their pods often specialize—fish here, seals there—while IUCN still says data deficient because apparent types may hide several species.
The English name flips a Basque sailors' phrase meaning whale killer, coined after they watched orcas attack bigger whales; since the 1960s orca has steadily displaced it. Despite claims linking Orcinus to Orcus and the underworld, the zoological naming code traces orca to a Latin word for a big-bellied pot. Old names include blackfish and grampus. Conrad Gessner published the first scientific description in 1558, from a carcass stranded in the Bay of Greifswald, and Linnaeus named the species in 1758.
Males usually measure 6 to 8 m and top 6 tonnes, with record animals reaching 10 m and over 10 tonnes; females run 5 to 7 m. Newborns weigh about 180 kg. Their family, 35 oceanic dolphin species, appeared around 11 million years ago, and studies disagree on the orca's closest relatives, variously naming the snubfin dolphins or the Lissodelphininae.
Off western North America researchers distinguish fish-eating residents, mammal-eating transients and offshores, each with distinct hunting methods and calls learned within family lines, which scientists treat as culture. A 2024 study proposed making residents and transients separate species; the Society for Marine Mammalogy instead ranked them provisionally as subspecies. Antarctica holds four more types, labelled A to D, and genetic work suggests some of them deserve species rank too. Mammal hunters in different oceans turned out not to be close kin.
Indigenous peoples of the Pacific Northwest, Australia and Peru revered orcas while Western sailors feared them, and whalers took them when larger species ran short. Public attitudes warmed in the 1960s partly through captive displays, now widely criticised. No fatal wild attack on a person has been recorded, though captive orcas have killed handlers. Southern residents joined the US endangered list in 2005, pressured by PCBs, prey loss and fisheries conflict.
Source: Orca
