Good link. Interesting article. Somewhere in the back of my mind, I keep thinking all they did was teach the deer to eat at the trough with a light shining over it. I'm sure that is not the case, and I believe there conclusions are probably correct - to a point. I'm sure the deer responded better to the blue light, which may mean something. I question though whether you can "infer" what colors deer see based on how our eyes work. The signals received by the deer's retinal rod cells (that in us sees blues) that is transmitted to the brain may not be interpreted the same as it would in a human brain. The eye does not "see", but instead captures the light with and then transforms that the information received into an nerve impulse that is then interpreted by the brain.
I ask myself, "what possible reason would a deer eye have for seeing the color blue the best?". What advantage would it give a deer to see blue better than others. I can't think of a single reason. Certainly not food. If you believe in the theory of evolution, the deer we know today were selected for/ successful enough to survive, based at least partly on the improvements in eye (and of course, the nose). I seriously doubt that they evolved their ability to see blues in order to avoid human hunters wearing bluejeans. Certainly, many, many, blue jean clad hunters were very successful while wearing blue.
I think that we only understand a small part of the story. Hmmmm.......
