SCIENCE

Mirror Image

The first evidence that elephants can recognize themselves

December 2006

By exposing elephants to mirrors, scientists have spotted a hidden side of the giant creatures: the ability to recognize themselves.

Self-recognition in mirrors is rare among animals. Until now, only people, apes, and debatably dolphins have demonstrated this ability. Most animals ignore their own reflections or, in the cases of monkeys and birds, perceive themselves as strangers.

Previous research has linked self-recognition with advanced social abilities such as empathy and deception, says evolutionary psychologist Gordon G. Gallup Jr. of the State University of New York at Albany. An animal that's aware of itself can likely infer the thoughts of others, he says.

Elephants are highly social and have large brains — traits that make them good candidates for self-awareness, explains Diana Reiss of the Wildlife Conservation Society and Columbia University.

To test that theory, Reiss and two colleagues from Emory University placed mirrors in the yard where three Asian elephants live at the Bronx Zoo in New York. All three elephants displayed unusual, self-directed behavior in front of the mirror. Such behavior included pulling their ears back and forth with their trunks and eating hay in front of the reflection, often swinging the bales as though testing the image.

"[People] used to think we were alone in many of our abilities," says Reiss. "This [study] presents an interesting picture as we try to understand the evolution of intelligence."

Only one of the elephants, named Happy, completed the highest level of mirror self-recognition, known as the "mark test." During part of the study, the researchers placed a white "X" above one eye of each elephant. After approaching the mirror, Happy touched the mark with her trunk 12 times in 90 seconds — a high rate for an atypical behavior.

To make sure the sight and not the feel of the "X" caused the excess touching, the researchers also placed an invisible "X" of the same texture above her other eye. Happy never tried to touch this false mark, Reiss' team reports in the Nov. 7 Proceedings of the National Academy of Sciences.

Happy's behavior, however suggestive, failed to convince psychologist Marc Hauser of Harvard University.

"It's not like when chimps sit in front of the mirror and stare at a spot and pick at it," he says.

Even if the elephant had recognized itself definitively, the mirror test leaves many unanswered questions about the animal's thought processes, Hauser explains. For example, monkeys have shown signs of self-monitoring on mental tasks even though they fail the mirror test.

The finding should be replicated, agrees Gallup, who created the mark test several decades ago. But the two elephants that failed to recognize the "X" should not diminish Happy's accomplishments, he says. After all, many people fail the mark test, including those with autism and babies younger than 18 months.

If the research does hold up in time, the result would be both surprising and exciting, says Gallup, because elephants don't share a common ancestor with people the way apes do.

"This kind of adaptation may represent a solution to similar problems in unrelated groups," he says. "This would represent a striking instance of convergent evolution."