Happy the elephant recognises herself in a mirror.

Credit: Diana Reiss/Wildlife Conservation Society.

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SYDNEY: Elephants can recognise themselves in mirrors, an ability which gains them membership of the cognitive elite, U.S. researchers say.

"We report a successful MSR [mirror self-recognition] elephant study and report striking parallels in the progress of responses to mirrors among apes, dolphins and elephants," said the researchers. They report their findings today in the U.S. journal Proceedings of the National Academy of Sciences.

Mirror self-recognition is considered a sign of self-awareness which, until now, has been observed only in humans, apes and dolphins. These animals - as well as elephants - all have large brains, complex social systems and high intelligence levels.

"It is interesting to wonder whether a sufficiently large and complex brain results in this kind of processing ability or whether other factors also play a role in its emergence," said co-author Diana Reiss from the Wildlife Conservation Society.

In the study, three Asian elephants were introduced to a huge, 'elephant-resistant' mirror at the Bronx Zoo in New York City. The female elephants, Happy, Patty and Maxine, were observed while they interacted with the mirror.

Humans, apes and dolphins typically go through four stages after being introduced to a mirror. In most cases, an animal will first engage socially with the reflection through visual, vocal or agonistic displays. Interestingly, the elephants in this study showed no social interaction behaviours.

The second stage of mirror self-recognition is physical inspection of the mirror. Maxine and Patty both threw their trunks over the mirror, reared up on their hind legs in order to peer over the top, and knelt down in front of the mirror, attempting to get their trunks underneath it.

The third stage is repetitive testing of the mirror. Each elephant tried out some vertical and horizontal head and body movements in front of the mirror, moving in and out of view of the mirror. The elephants also used the mirror as a tool to investigate their own bodies. They brought food over to the mirror and watched themselves eat. They also inspected the insides of their mouths and pulled on their ears with their trunks.

The fourth and final stage is a test. For the scientists to be sure that the elephants were recognising themselves in the mirror, they had to pass the standard 'mark test'.

The elephants each had two marks painted on their heads. A visible X was painted on the right-hand side and an invisible mark was painted on the left-hand side. The elephants were only able to see the visible mark if they looked in the mirror. The scientists observed the elephants to see if they would touch the visible mark.

Happy repeatedly touched the visible X after seeing it in the mirror. The other two elephants did not touch the visible mark on their foreheads, and none of the elephants touched the invisible mark.

"Only one elephant, Happy, passed the mark test," explained Reiss. But only one elephant needed to pass the 'mark test' to demonstrate that elephants are capable of self-recognition and self-awareness. "This is consistent with reports of tests with the great apes. Not all of the apes that are tested pass the mark test, nor do all children it turns out," she said.

According to the Reiss, this study shows that the ability to distinguish oneself from others has evolved independently in several branches of animals. "This is a marvelous example of cognitive convergence," she said.