Although dolphins are apex predators, they are sometimes eaten by sharks and killer whales; however, their primary predator is mankind. Dolphin pods attack sharks on sight, circling protectively around the weakest member of their group and attacking until the shark is driven away or killed. Dolphin remains have also been found in orca stomachs. Humans kill dolphins either by accident or intentionally during large-scale fishing operations.
Multiple countries kill dolphins for food. Natives of Japan consider dolphin meat to be a delicacy, while the Faroe Islanders consider the hunting and eating of cetaceans a longstanding cultural tradition. In Latin American countries, overfishing has depleted the nearby waters, causing the death of many dolphins. Fishermen also kill dolphins and porpoises to prevent them from hunting for prey in specific areas. During large-scale fishing expeditions, dolphins become entangled in drift nets, and they are unable to swim to the surface for air; many maim themselves in their efforts to escape. Tuna fishing is considered especially hazardous to dolphins because large schools of tuna swim below dolphins. Although surviving dolphins are usually released back into the ocean, Dolphin's World estimates that large fishing expeditions have killed at least 30 million dolphins since 1960.