In 1998, a team of researchers marked the foreheads, backs, and flippers of a pair of show dolphins with triangles and circles, then placed a mirror in their tank. The two dolphins swam to it and immediately began checking out their new tattoos, which were on areas of their bodies they couldn’t normally see, thereby demonstrating that they could recognize their own reflections—a test of self-awareness that only chimpanzees and humans had passed at the time. The finding was a breakthrough in dolphin research and a milestone in the field of animal cognition. But it also sowed an uncomfortable seed in the minds of some researchers: If dolphins are as self-aware as people, how can we keep them locked up in concrete pens? Some researchers have since launched a crusade to free all dolphins from captivity. But they are swimming upstream. Although their colleagues are concerned about the welfare of dolphins, most have concluded that captive research is both the best way to learn about the intelligence of these creatures and the best way to protect them in the wild.
Source and full report: Science