From Nature:
Elephants possess the highly cerebral ability to recognize their own jumbo reflections in mirrors, scientists have found. Traditionally, only an elite group of animals including humans, chimpanzees and orangutans have been proved to be capable of self-recognition in a mirror. A lone study several years ago also reported that dolphins could recognize their own gaze in a glass. To study the elephants’ behavior, the researchers placed an “elephant-proof, jumbo-sized” mirror, 2.5 metres high by 2.5 metres wide, inside the enclosure of three female Asian elephants (Elephas maximus) at the Bronx Zoo in New York City. The team used a still camera on a roof to observe the animals over a period of five months.
Upon entering the yard, all three elephants ran to inspect the mirror. The elephants, named Happy, Maxine and Patty, immediately investigated the surface by sniffing and touching it with their trunks — even attempting to climb the mirror to look behind it and kneeling down to look under it. They didn’t display threatening behaviour such as trumpeting, which might have been expected if they saw the images as intruder elephants.
More here.