Jane Goodall
In contrast to the peaceful and affectionate behaviours she observed, Goodall also found a mean side of chimpanzee nature at Gombe Stream. She discovered that chimps will systematically hunt and eat smaller primates such as Colobus monkeys. Goodall watched a hunting group isolate a colobus high in a tree, block all possible exits, then one chimpanzee climbed up and captured and killed the colobus. The others then each took parts of the carcass, sharing with other members of the troop in response to begging behaviours. The chimps at Gombe kill and eat as much as one-third of the colobus population in the park each year. This alone was a major scientific find which challenged previous conceptions of chimp diet and behavior.