Humans see their reflections in mirrors and recognize them to be themselves in daily life. They do so not by looking at their chest, tummy or limbs, or movements in mirrors. They recognize themselves in mirrors by their faces pure and simple. In doing so, they actually check their own faces in mirrors against the images of their faces in mental. This process is very similar to recognizing someone else by face. Then we found that fish also recognize themselves in a mirror by their face.