Some of the characters in the Over the Edge series and the related romance series are marsupial humanoids. Not only do marsupials have two unified brain hemispheres and weird sexual apparatus, but they also see into the ultraviolet spectrum. What does that look like? It's quite difficult for us to imagine, harder for some of us than others because we don't all see the same colors within the narrow and of colors humans can see. Men are more likely to be unable to see certain colors and a few women might be able to see more colors than everyone else. The beast with the best color vision in the world is a particularly viscous shrimp--the mantis shrimp, who is sufficiently violent it can crack an ordinary aquarium wall.
The podcast is by RadioLab and is pretty interesting. If you've got an hour, give it a listen, if you don't right now, come back and listen when you do have the time. Enjoy. Colors by RadioLab