Humans aren’t the only ones who hate a bum deal, it turns out.

In a study, brown capuchin monkeys trained to exchange a granite token for a cucumber treat often refused the swap if they saw another monkey get a better payoff — a grape.

Instead, they often threw the token, refused to eat the piece of cucumber, or even gave it to the other capuchin after viewing the deal, Emory University researcher Sarah Brosnan said.

She said the results indicated man and monkey might have inherited a sense of fairness from an evolutionary ancestor.

“This implies we evolved this way,” said Brosnan, whose work with colleague Frans B.M. de Waal is reported in today’s issue of the journal Nature.

The researchers, at Emory’s Yerkes National Primate Research Center, studied five female monkeys, testing them two at a time.

When both monkeys were given a cucumber slice after handing over the token, they completed the trade 95 percent of the time.

But when one was given the tastier grape for the same amount of work, the rate of cooperation from the other monkey fell to 60 percent, with the cheated primate sometimes throwing the token, refusing the cucumber or giving the cucumber to the other monkey. And when one didn’t have to do anything to get a grape, the other made the trade for the cucumber only 20 percent of the time.

“They were not happy with me,” Brosnan said.