Bonobos, one of humans' closest relatives, generally live in female-dominated societies, despite the fact that the males are typically larger and stronger. After three decades of observations, researchers have discovered that "girl groups" chase males out of trees, secure food for themselves, and have a female-dominated social ladder. "It’s very clear that you don’t want to overstep as a male bonobo," study author Martin Surbeck said. This system could help protect females from male violence. (AP News)