Humans, chimpanzees and dolphins were believed to be the only animals capable of recognizing themselves in a mirror, but now a recent study showed elephants also have this ability.

Researchers set up a cumbersome experiment at the Bronx Zoo in New York, spending weeks to install a huge mirror, 2.4 meters high and 2.4 meters wide in the pen of three female Asian elephants.

"Maxine, Patty and Happy (the elephants' names) immediately went over to the mirror when they were let out, which was really a surprise to us because most animals, when exposed to a mirror, act immediately as if it were another animal," said Josh Plotnik, a graduate student who worked on the study.

The elephants used the mirror to inspect themselves, moving their trunks to look inside their mouths, and tested the mirrored images by making repetitive, rhythmic movements.

Happy, a 34-year-old elephant, even passed an important test of self-recognition, known as the "mark test."

Each elephant was marked with visible paint on its forehead, and Happy repeatedly used the tip of her trunk to touch the mark. That response required an understanding that the mark was not on the mirror but the elephant's body, the researcher said.

An invisible "sham" mark was also placed on each elephant, to see if the feel or smell of the mark might cause him or her to touch that spot. Happy only touched the visible mark with her trunk.

The other two did not, but the researchers were not surprised.

"As a result of this study, the elephant now joins a cognitive elite among animals commensurate with its well-known complex social life and high level of intelligence," said Frans de Waal, one of the authors of the study.

The researchers hope other animal experts will try to replicate their findings with animals and other species.

Source:Xinhua/Agencies