Did you know that some animals do in fact have a third eye? Some lizards, amphibians and fish have a small dot at the centre of their heads, this is the pineal eye. Although it's not functional anymore in most of cases, there is an endangered species, the tuatara, that lives on a few islands in New Zealand, whose pineal eye actually works! Besides being similar to a compass, it allows them to see light and dark, so if you tried to snatch the tuatara, your shadow would give you away before your footsteps did!