Artistic color theory the modern phrenology #5: bird brained
Jun 4th, 2007 by Brad
We are taught human vision is wonderful and near perfect. We all like to believe we are unique and special. We are only tri-chromatic which means we really only have 3 color sensors (cones) in our eyes. Birds are tetra-chromatic and some butterflies are even penta-chromatic. Feeling left out like I do? As it turns out our color sensors are not even evenly spaced in the visible spectrum. Birds cones are. They even have little globules of filtering oil on top of each to make them even more refined (drop of blue oil to filter blue light before it gets to the blue cone, etc.)
By the way, we are better than most mammals who are di-chromatic, yes fido doesn’t see in black and white, she’s just a bit more color blind than we are. In fact this is a clue to evolution as we likely had 4 cones and lost 2 as small mammals running in tunnels (also lost the oil globules as that allows more light to hit the cones at night). Then another mutation in great apes of the green cone gave us an imperfectly spaced red cone back.
One theory is the evolutionary advantage of red is not to find brightly colored fruits, but to allow great apes (leaf-eaters) be able to distinguish a younger and better eating young green (slightly red tinged leaf). You can read more about this in research by Peter Lucas {sorry I have printed journal articles, but I can’t find them online since I’m in a bit of a hurry).
You can read more specifically about bird vision and our likely evolutionary mammalian evolution in an interesting article in Scientific American (July 2006) called “What Birds See: Evolution has endowed birds with a system of color vision that surpasses that of all mammals, including humans” by Timothy H. Goldsmith.
