In just five hours, an average farm pig can learn how to interpret an image in the mirror and use it to find hidden food.
Scientists consider the ability to use a mirror a sign of complex cognitive processing and an indication of a certain level of awareness. In addition to humans and some primates, dolphins, elephants, magpies and a famous African grey parrot named Alex have all been known to retrieve objects or remove marks on their body using a mirror. Now it looks like pigs should be added to the list of clever critters that can master a mirror: After spending five hours with a mirror in their pen, seven out of eight pigs could use the reflection to find a hidden bowl of grub.
“This is the first demonstration of the ability of pigs to use mirrors,” animal behavior expert Donald Broom of the University of Cambridge wrote in an e-mail. “Finding sophisticated learning and awareness in animals can alter the way that people think about the species and may result in better welfare in the long run.” Broom co-authored the paper published this month in Animal Behaviour.
Like most animals, the pigs were immediately curious when researchers placed the shiny, reflective object in their pen. They approached the mirror until they bumped into it with their snout, and then checked to see what was behind the mirror. The pigs spent an average of 20 minutes gazing at their reflection, often turning in different directions to inspect themselves from several angles.
“We have no conclusive evidence of a sense of self,” Broom wrote, “but you might well conclude that it is likely from our results.”