There was an incident in California recently, last 5 yrs or so, at a Chimpanzee rescue place(where circus or zoo or testing animals go to die). 2 males broke free and attacked some visitors to the park. A mans face AND genitals were removed. That is how they do things, tear off the face and genitals, and then you are theirs. There is also footage in Africa of troops of Chimps hunting down and eating other primates. These animals lives and hierarchy is based in confrontation and violence... and they are our closest relatives in the primate world, being separated by 1 pair of chromosomes, it is easy to see why some people are much more prove to violence, murder, cannibalism etc... than others.