Fair or unfair? Even Capuchin monkeys recognize unequal pay

You do your job, you get paid. Life is good, right?

Unless you're a monkey -- and you see your buddy is getting a better reward than you for doing the exact same task. 

Frans de Waal, a primatologist and Emory University professor, conducted an experiment on Capuchin monkeys about 10 years ago, which he dubbed the “Fairness Study.” During the study, two monkeys were each asked to perform a task for a reward. If you’re a monkey, a chunk of cucumber is an acceptable reward, but you know you’re really keeping up with the Joneses when you get rewarded with grapes.

In the viral video, uploaded to YouTube in May, the first time a monkey completes the required task (which involved handing a lab worker a small rock), he is paid with a small chunk of cucumber. But then the monkey discovers his buddy is rewarded with a grape -- valuable currency in the monkey world -- for doing the exact same job. Well, that wasn’t going to fly. What was going to fly were chunks of cucumber as the first monkey, now green with envy, pounds the table in protest and rattles the walls of his cage.

"So, this is basically the Wall Street protest that you see here," says de Waal, referring to the Occupy Wall Street movement.

De Waal as his colleague, Sarah Brosnan, published their findings in the journal Nature in 2003. The video from May has gone viral, with more than 1.2 million views. 

Joy Jernigan contributed to this report. Dana Macario is a Seattle-area writer who, like the Capuchin monkeys, has been known to have a case of the wants now and then.