In Defense of Dolphins: The New Moral Frontier, $28.95 (2007)  

Thomas I. White  is a philosopher and professor of business ethics.   He argues that dolphin intelligence and social ability qualifies them as “nonhuman persons” who deserve rights.   Some may find his concept eccentric or extreme.   However, in the process he provides a very good survey of current dolphin research and also describes practices that most would agree are necessarily cruel.