Those clever little monkeys are on strike again. And I don't mean the Writers Guild. No, I'm talking about the tufted capuchin monkeys at Yerkes Primate Research Center. Those headstrong primates have put down their feet—all four of them—and refused to work for unfair wages. Their grievances are presented in the current online edition of the Proceedings of the National Academy of Sciences. To examine capuchins' sense of fairness, Frans de Waal and his colleagues at Emory University designed a bartering task in which monkeys are given tokens they can then exchange for food. Some monkeys get a plain old cucumber slice, others get a coveted grape. What the researchers discovered is that when monkeys who get salad fixins see their friends get fruit, they basically refuse to play anymore. But were the monkeys really reacting to inequity.