Both humans and animals communicate a lot through their body postures. A cat, when energy humps its back and its skin ruffles up so that it appears bigger and more dangerous. In this way, it warns its opponent not to come near. Humans frown when in doubt and smile when happy. We use the thumbs up or the thumbs down signs as common gestures of approval or disapproval by extending the thumb upward or downward. We also make use of a universal sign language; we know what an index finger on the lips or a waving hand is trying to tell us. But watch out: signs do not mean the same all over the world – if you make an ‘O’ with the index finger and the thumb, it means ‘okay’ in USA, but at other places it is an insult.
