Ravens and other members of the corvid family (crows, jays, and magpies) are known to be intelligent. They can remember individual human faces, expertly navigate human environments (like trash cans), and they even hold funerals for their dead.

Some ravens, it seems, even know the art of making a deal.

A new paper published in the journal Animal Behavior tested how well a raven could judge a deal that was "fair" or "unfair."

The study was conducted by researchers from the Lund University in Sweden, the University of Vienna in Austria, and others. Co-author Jorg Massen is a post-doc at the University of Vienna specializing in cognitive biology.

"This sort of cooperation is a part of [a corvid's] complex social life,"