Dolphins have been declared the world's second most intelligent creatures after humans, with scientists suggesting they are so bright that they should be treated as "non-human persons". Studies into dolphin behaviour have highlighted how similar their communications are to those of humans and that they are brighter than chimpanzees. These have been backed up by anatomical research showing that dolphin brains have many key features associated with high intelligence. The researchers argue that their work shows it is morally unacceptable to keep such intelligent animals in amusement parks or to kill them for food or by accident when fishing. Some 300,000 whales, dolphins and porpoises die in this way each year. "Many dolphin brains are larger than our own and second in mass only to the human brain when corrected for body size," said Lori Marino, a zoologist at Emory University in Atlanta, Georgia, who has used magnetic resonance imaging scans to map the brains of dolphin species and compare them with those of primates. Thomas White, professor of ethics at Loyola Marymount University, Los Angeles, who has written a series of academic studies suggesting dolphins should have rights, [said], "The scientific research ... suggests that dolphins are 'non-human persons' who qualify for moral standing as individuals.