Chimpanzees have a reputation for being aggressive, while bonobos are often seen as their peaceful counterparts. This contrast has frequently been used to explain different sides of human nature. However, a new study by Utrecht University behavioral biologists Emile Bryon, Edwin van Leeuwen, Tom Roth and international colleagues shows that, in zoos, chimpanzees are not more aggressive than bonobos. The study was published in Science Advances.