Some researchers have begun to question the notion that dolphins are the super-intelligent creatures they've been made out to be. Pavel Golovkin/AP hide caption

itoggle caption Pavel Golovkin/AP

Demonstrators at a rally in Tokyo on August 31 protest against the start of Japan's annual dolphin hunt in Taiji. Yoshikazu Tsuno/AFP/Getty Images hide caption

itoggle caption Yoshikazu Tsuno/AFP/Getty Images

An elephant at the Emmen, Netherlands, zoo stands at the edge of a ditch in 2009, a day after another elephant fell into the ditch and died. Olaf Kraak/AFP/Getty Images hide caption

itoggle caption Olaf Kraak/AFP/Getty Images