7 Most Dangerous Apes / Monkeys That We Should AvoidCape Baboon. These are among the largest monkeys as well as one of the most dangerous monkeys to avoid. Chimpanzee. It comes as a surprise to know that chimpanzees are one of the most dangerous apes we should avoid. Gelada. With giant manes and weird flat faces, geladas are actually very calm and peaceful. Gorilla. Macaque. Mandrill. Olive Baboon.