Doing so, the reasoning goes, means the animal understands when it is looking at itself rather than another animal. In the earliest studies on elephant self-awareness, researchers placed a one by 2.5–meter mirror outside the bars of an enclosure, angled in such a way that the animals could see only the upper thirds of their bodies. The elephants reacted to the reflection as they would to another elephant, raising their trunks in greeting. When the scientists dabbed the elephants’ faces with white cream, the animals failed to recognize that the marks were on their own bodies.
But what if the experimental design itself prevented the elephants from understanding that they were looking at themselves in the mirror? After all, elephants identify one another primarily by touch, scent and sound—not sight—and the animals in the study could not physically investigate the mirror. So Reiss, de Waal and Plotnik decided to redo these experiments, this time allowing the elephants to use all their senses.
In 2005 the trio constructed a 2.5 by 2.5–meter shatterproof mirror and bolted it to a wall surrounding an elephant yard at the Bronx Zoo in New York City. Three female Asian elephants named Patty, Maxine and Happy were free to approach and inspect the sturdy mirror at their leisure. When they first encountered the contraption, Maxine and Patty swung their trunks over it and attempted to scale the wall to which it was attached, as though checking to see whether another elephant was hiding behind the glass. When they found nothing, all three elephants swayed their trunks and bobbed their heads while looking right into the mirror, just as we might wave our hands to see whether a shadow is our own.
They stared at their reflection and stuck their trunks inside their mouths as though searching for snagged spinach. A few days later the scientists painted a white X onto the right side of each elephant’s face. Maxine and Patty did not seem to notice the marks, but Happy began to touch the X on her face with her trunk after strolling past the mirror a few times. Eventually she faced her reflection and repeatedly swiped at the painted part of her face with the tip of her trunk. The fact that only one of three elephants noticed the X on its face might seem a disappointing performance, but it is actually quite remarkable. Reiss points out that even in studies with chimpanzees—which most researchers accept are self-aware—sometimes fewer than half pass the mirror test.