Why'd the chicken cross the road? Cause it saw the light was green

• Color receptor organization in the retina chickens exceeds that of mammals and most other retinas observed in nature.
• But why is that? One explanation:
• Millions of years ago, during the evolution of birds and mammals, our ancestors were primarily nocturnal, adapting night-vision receptors called rods for survival from the threat of larger predators.
• Birds on the other hand, widely believed to be descendants of dinosaurs, were able to survive during the daytime and further develop their light-sensing receptors called cones.
• Humans have retina cones sensitive only to red, blue, and green wavelengths.
• Birds share these and have other receptors to detect violet and ultraviolet (UV) wavelengths, and another specialized receptor believed to detect motion.
• Relevance:
• Could lead to new understandings of inherent problems in human eyes and ideas on how to fix them.

http://www.physorg.com/news185539169.html