ShareThisBy LEE BOWMAN
Sunday, November 19, 2006
Researchers have determined that elephants, along with people, great apes and dolphins, are part of an elite group of species that are able to recognize their own reflected image.
Biologists had expected that elephants, given their social complexity and behaviors, should be able to recognize themselves in a mirror but several previous tests using relatively small mirrors that the elephants couldn't reach had been unconvincing.
In a Bronx Zoo study, scientists used an 8-by 8-foot mirror that the pachyderms could "touch, rub against and try to look behind,'' said Joshua Plotnik, a researcher at the Yerkes National Primate Research Center at Emory University in Atlanta, and lead author of a report on the tests published online Monday by the Proceedings of the National Academy of Sciences.
While the mirror was in the elephant yard, all three elephants tested the mirrored images by making repetitive body movements and using the mirror to inspect themselves, such as moving their trunks to look inside their mouths, a part of the body they usually can't see.
The elephants didn't react socially to their own image or mistake it for another elephant, as many animals do when they see their reflection.
"The social complexity of the elephant, its well-known altruistic behavior, and, of course, its huge brain, made the elephant a logical candidate species for testing in front of a mirror," said Plotnik, who worked on the study with Yerkes colleague Frans de Waal and Diana Reiss, a researcher at the Wildlife Conservation Society in New York.
One of the elephants also passed a standard test known as the mark test. Each elephant was marked with a highly visible paint on its forehead _ a place it could not see without a mirror, and also got a splash of colorless face paint, which controlled for whether an animal reacted only to the reflection in the mirror, as opposed to the odor or feel of the paint.
Like great apes and human children, the elephant only paid attention to the mark it could see in the mirror.
"As a result of this study, the elephant now joins a cognitive elite among animals," de Waal said, noting that it appears the ability to distinguish oneself from others evolved independently in several branches of animals.
"Although elephants are far more distantly related to us than the great apes, they seem to have evolved similar social and cognitive capacities making complex social systems and intelligence part of this picture," de Waal said.
On the Net: www.pnas.org
