Recognising your own reflection has been termed Mirror Self Recognition (MSR) by scientists, and it is an indicator of self-awareness. Like humans, some animals recognise their mirror image and are aware of themselves in a manner once thought to be unique to humans.
To prove chimps can recognise their own refection, they were trained to touch a coloured dot in their enclosure. Each time they touched this spot, they were rewarded with food and when a spot was placed on their forehead they were allowed access to a mirror. Rather than touching the spot reflected in the mirror, like many other primates would, each chimp upon seeing its reflection touched the spot on its own forehead.
2. Bottlenose dolphins
Similarly to the chimpanzee experiment, dolphins were marked with waterproof pens, or pens filled with water. Once marked with either ink or water, the dolphins raced to the mirror to see the mark, and those marked with ink spent a long time looking at the exact place the mark was. Those that were sham marked with water took a quick glance in the mirror, then simply swam away.
Magpies were marked with either a bright coloured spot (yellow or red) or a black spot that blended in with their black feathers. They were given the choice between looking into a mirror, and looking at a non-reflective plate, and all the birds chose to spent time in front of the mirror, looking at their brightly coloured marks under their chin.
4. Asian elephant
When given access to a mirror, elephants performed a series of behaviours. First, they behaved socially towards their reflection, as if it were another elephant, before physically inspecting the mirror by looking behind and around it. The elephant would then test the mirror by making repeated movements, before making the realisation that the reflection was its own mirror image.