This allows other chimps in the area to be aware and steer clear of this monkey. If you’ve ever watched a monkey at the zoo, when they are afraid, chimpanzees often begin to grin. This grin, however, is not a happy grin but is instead known as the “Grin of Fear”. The “Grin of Fear” is often closely compared to a human’s nervous smile when laughing at an awkward joke or feeling uncomfortable in a situation. Finally, chimps must find a way to proclaim their dominance to one another and they do this by slapping their hands together, stomping their feet and hurling rocks (very similar to their angry gesture). These gestures are used in order to show a chimp’s aggressiveness without actually having to prove it in a fight.