LOU WATERS, CNN ANCHOR: Now let's get to the animals. Marine biologists know dolphins are smart. We've known that for a long time. They figured that out a long time ago.</s>NATALIE ALLEN, CNN ANCHOR: But now research shows they possess a specific kind of awareness and that's leading researchers to think in a new way about intelligence and evolution. We get our report from Denise Dillon.</s>DENISE DILLON, CNN CORRESPONDENT (voice-over): Dolphins aren't just athletically inclined. For years, we've known they're intelligent. But now researchers may have uncovered something even more remarkable about them. Marine biologists say these two bottlenose dolphins, Presley (ph) and Tab, at the New York Aquarium can recognize themselves in mirrors, a reflection of their intelligence.</s>DIANE REISS, SCIENTIST: What is so important about that is that in the past we have only been able to demonstrate this in primates, in humans and the great apes. And no monkey species or other species have shown this ability.</s>DILLON: So, how do we know they actually recognize themselves and aren't just playing? Well, researchers say they display different social responses, and to test that, researchers put markings on the dolphins' bodies in black ink. The dolphins then swam to the mirrored walls to look at the marks. Researchers also say they spent more time in front of the mirror when their bodies had the marks. Not only is self-recognition in dolphins and apes considered a benchmark of intelligence, the finding could change what we know about evolution.</s>REISS: Showing this kind of convergence in cognitive ability that animals with very different brains, with different evolutionary histories can accomplish the same task, like mirror self-recognition, suggests that we really need to look at our theories about evolution of intelligence in a new light now.</s>DILLON: Experts are now trying to determine if this self- recognition in dolphins means they are capable of much more than we ever imagined. Denise Dillon, CNN.
Dolphins Show Another Sign of Their Intelligence