Bonobos

That's because rather than fighting, bonobos turn to sex as a way of dealing with disputes. It's also used as a greeting, as a way to apologize, as a way to ask for some extra food and more. And sex isn't just limited to mounting animals of the opposite gender – masturbation, mutual masturbation and homosexual romps are all encouraged by these frisky critters. In fact, the only thing that seems off limits is for a mother to engage in sexual activities with her son – hey, you've got to draw the line somewhere.