Orca

The orca (Orcinus orca), also called killer whale, is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus Orcinus and is recognizable by its black-and-white patterned body. A cosmopolitan species, orcas can be found in all of the world's oceans in a variety of marine environments, from Arctic and Antarctic regions to tropical seas. Orcas are apex predators and have 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, other species of dolphin, and whales. They are highly social; some populations are composed of highly stable matrilineal family groups (pods). Their sophisticated hunting techniques and vocal behaviors, which are often specific to a particular group and passed across generations, have been described as 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, which swim in British Columbia and Washington waters, 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 feature strongly in the mythologies of indigenous cultures, and their reputation in different cultures ranges from being the souls of humans to merciless killers. Orcas are commonly referred to as "killer whales", although as part of the family Delphinidae, the species is more closely related to other oceanic dolphins than to other whales.