Dolphins are not only the world's smartest animal after humans, they're so intelligent they deserve to be classed as "non-human persons." So say scientists who argue their research on dolphins' brains shows it is unethical to keep such animals captive in amusement parks or to kill them for food or accidentally through fishing, the London Times reports.
Recent studies suggest dolphins have individual personalities and a strong sense of self, and can think about the future. Bottlenose dolphins can also recognize themselves in a mirror and use it to inspect parts of their bodies, an ability previously thought limited to humans and great apes. They can learn basic symbol-based language and adapt "cultural" behavior learned from other dolphins--all of which makes them likely more intelligent than chimpanzees, which are believed to be at about the intellectual level of a three-year-old child.