Quote Originally Posted by cornflake View Post
Ravens refuse to associate with humans who cheat them, or other ravens who steal.
And Capuchin monkeys have a fairness ethic. They get angry about unequal rewards when they perform tasks in an experiment: https://www.youtube.com/watch?v=meiU6TxysCg

If you reward them both with a cucumber, they're fine with it. But if you give one a cucumber and one a grape...