When his sight was blocked, Tanner used other senses to figure out what the other dolphin was doing and copied it, the researchers at the Dolphin Research Center in the Florida Keys explained.

Researchers at the non-profit center hope to conduct further studies to "map the dolphin mind" in order to learn more about the evolution of human cognition.

"Looking at an animal which is so far removed from us and yet shares some cognitive abilities, tells us something about us," said Dr. Kelly Jaakkola, the center's research director.

The ability to imitate is rare in animals. Primates such chimpanzees can sometimes do it but only humans and dolphins are proficient, added Jaakkola. "Most people think, 'Monkey see, monkey do.' It's a complete myth. Dolphins are really good at it. Aside from humans, they're the best at it."

CLICKS AND WHISTLES

In their test, the researchers gave Tanner a familiar hand signal asking him to imitate another dolphin, and then covered his eyes with soft latex eyecups to block his sight. Then they used hand signals to ask the partner dolphin to do a specific trick, and within seconds, Tanner imitated the other dolphin.

They tested him repeatedly on 31 different behaviors in sessions spread over 11 weeks. In some sessions he was blindfolded and in others he was not. In both cases, he was able to imitate the other dolphin's behavior far more often than would be expected by chance, the researchers said.

When blindfolded, he imitated the vocal behavior with 75 percent accuracy, motor behavior with 41 percent accuracy and combined behavior with 50 percent accuracy.

Researchers were uncertain whether Tanner figured out what the other dolphin was doing because he recognized the sound that action made or whether he used echolocation, a sensory system bats and dolphins use to determine the direction and distance of objects by how long it takes an echo to return.

"In either case, he's problem solving," Jaakkola stated. "That level of flexibility in imitation has never been seen in a non-human animal."

Tanner was chosen for the study because he "really loves playing games" and was comfortable with the eyecups, Jaakkola explained. He was partnered in the tests with two other males who live in the same lagoon.

Tanner was born in captivity but dolphins in the wild are known to imitate each other. Male dolphins do synchronized displays around females, with one leading, the other copying.

Dolphins also copy each other's distinctive signature whistles, which act as names. They call out their own to announce their presence and imitate another's whistle to call to that animal.

The Florida researchers want to conduct further studies to see if dolphins can learn new tricks while blindfolded. They hope that by demonstrating dolphins' intelligence, they will give humans more incentive to conserve them.