Dolphins, orcas, seals, and other marine mammals are kept in aquariums worldwide. Their complex social and cognitive needs raise serious welfare questions in captive settings.
Marine mammals evolved for vast ocean environments with complex social structures and cognitive stimulation. Even large aquarium pools represent a tiny fraction of wild home ranges. Cetaceans in particular suffer in captivity — orca dorsal fin collapse is nearly universal in captive males and indicates chronic stress. Behavioural indicators including stereotypies, aggression, and altered sleep patterns are common. While some aquariums contribute to research and rescue rehabilitation, display of cetaceans for entertainment cannot meet their welfare needs and is being progressively restricted worldwide.