The killer whale (Orcinus orca), also referred to as the orca whale or orca, and less commonly as the blackfish, is a toothed whale belonging to the oceanic dolphin family. Killer whales are found in all oceans, from the frigid Arctic and Antarctic regions to tropical seas. Killer whales as a species have a diverse diet, although individual populations often specialize in particular types of prey. Some feed exclusively on fish, while others hunt marine mammals such as sea lions, seals, walruses, and even large whales. Killer whales are regarded as apex predators, lacking natural predators.
Captive orcas (killer whales) are large predatory marine mammals that were first captured live and displayed in exhibitions in the 1960s, and soon became popular attractions at public aquariums and aquatic theme parks due to their intelligence, trainability, striking appearance, playfulness in captivity, and sheer size. However, the captive environment usually bears little resemblance to their wild habitat, and the social groups that the killer whales are put into are foreign to those found in the wild. As of 13 August 2013, there are 45 orcas are in captivity worldwide, 32 of which are captive-born. The practice of keeping killer whales in captivity is controversial.