Orca
The orca (Orcinus orca), or killer whale, is a toothed whale that is the largest member of the oceanic dolphin family. It is the only extant species in the genus Orcinus. Orcas are recognizable by their black-and-white patterned body. A cosmopolitan species, they are found in diverse marine environments, from Arctic to Antarctic regions to tropical seas.
For other uses, see Orca (disambiguation).
Orcas are apex predators with a diverse diet. Individual populations often specialize in particular types of prey. This includes a variety of fish, sharks, rays, and marine mammals such as seals and other dolphins and whales. They are highly social; some populations are composed of highly stable matrilineal family groups (pods). Their sophisticated hunting techniques and vocal behaviors, often specific to a particular group and passed along from generation to generation, are considered to be manifestations of animal culture.
The International Union for Conservation of Nature assesses the orca's conservation status as data deficient because of the likelihood that two or more orca types are separate species. 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. In late 2005, the southern resident orcas were placed on the U.S. Endangered Species list.
Orcas are not usually a threat to humans, and no fatal attack has ever been documented in their natural habitat. There have been cases of captive orcas killing or injuring their handlers at marine theme parks. Orcas also feature strongly in the mythologies of indigenous cultures, and their reputation in different cultures ranges from being the souls of humans to merciless killers.
Naming
Orcas are commonly referred to as "killer whales", despite being a type of dolphin.[6] Since the 1960s, the use of "orca" instead of "killer whale" has steadily grown in common use.[7]
The genus name Orcinus means "of the kingdom of the dead",[8] or "belonging to Orcus".[9] Ancient Romans originally used orca[10] (pl. orcae) for these animals, possibly borrowing Ancient Greek ὄρυξ (óryx), which referred (among other things) to a whale species, perhaps a narwhal.[11] As part of the family Delphinidae, the species is more closely related to other oceanic dolphins than to other whales.[12]
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.[13]