Monkeys and apes
These animals are most similar to humans, creating a natural bond and some pitfalls as well. Some diseases carried by monkeys and apes can be easily transmitted to humans. Even a small monkey can bite, potentially transmitting a virus like hepatitis C. Larger apes, such as chimpanzees, orangutans and gorillas are powerful animals capable of mauling a human if they feel threatened.
Sometimes even chimps kept as pets have harmed their owners. It could be due to aggressive tendencies, illness or even frustration, say experts. In any case, the one thing that can't be underestimated is their brute strength.
"The chimpanzee has strength for a human that is utterly incomprehensible," Frans de Waal, lead biologist from the Yerkes National Primate Research Center, told Scientific American. "People watch pro wrestlers on TV and think they are strong. But a pro wrestler would not be able to hold a chimpanzee still if they wanted to."