False Eyes

FROM Daily Speculations by Victor Niederhoffer

It's common among fish and butterflies to have false eyes, usually directly opposite from the placement of the real eyes.

There appear to be three reasons for this. The eyes often mimic dangerous prey like snakes and scare off potential predators. The eyes also serve to fool predators who focus on the eyes of the prey and try to approach from the opposite direction so as not to be seen. The false eyes allow the butterfly or fish to escape in exactly the opposite direction from what is expected, after getting a good look at the killer. Finally, sexual selection seems to be involved with the false eyes being a conspicuous mark of health and attraction to the opposite sex, thereby increasing reproductive potential.