
Humans and animals come hand in hand. Humans do in fact differ from animals in a way you probably not normally think of. Humans have muscles in our faces which allow us to create facial expressions to show how we are feeling, for example: happy, sad, confused, scared, angry, and excited. Facial expressions are way of telling others how we are feeling; for instance, the smile. Some scientists think the origin of the smile goes way back to when humans were more primitive, when parting the lips into a smile and showing your teeth was a way of telling someone else “Don't worry, I'm not going to bite you”! An interesting thing about the smile is that scientists have discovered that it is linked to the special chemicals in our brains which make us feel happy. This means that if you are feeling sad, smiling can actually help to make you feel better.