http://anthro.palomar.edu/primate/color.htm
First off, I would like to say how much I still appreciate Dunn as an author, and I will discuss his writing style further in our discussion this week. One example though, is his ability to link past occurrences to the modern actions of humans, a task Bulliet failed to achieve (in my opinion). He mentions in his novel Wild Life of our Bodies, that old world monkeys had a full spectrum similar to humans of color vision, probably for discerning which fruit was ripe. Apparently, this trait has been passed on to New World monkeys, but it is far less common than with the ancestors.
I have always sort of struggled with concepts of evolution because I believe in the “Creation” theory for the development of mankind, though, over time, I have come to accept that natural selection could have absolutely modified and even killed off thousands of species. That being said, I wanted to explore first how scientists know that monkeys saw or can see color, but also find some other theories on why that is. Shockingly, the best answers I found as to how scientists can tell which colors animals can see appeared in a yahoo blog. Simply stated, researchers can tell from cones in the eyes of the animal whether he can determine red from green (the true test for color blindness), which Dunn briefly mentioned in the passage.
Now, as to why the monkey used to see in full color as opposed to the New World monkeys, I found the article I have attached to this post. You may wish to read it for yourself, but in summary, the article verified Dunn and Isbell’s proposal that monkeys had to use their vision to see whether the fruit was ripe or not. Furthermore, the article also presented that females develop red skin near sexual organs (sorry for that visual) that would help a male with a poor sense of smell (causing him difficulty in sensing female pheromones) mate. Other than these two proposals for the monkey’s ability to see red, the article said there were not many other accepted proposals for the monkey’s inherited ability to distinguish colors.
One discrepancy I would like to point out in the article, is that it gives credit, for the theory of the monkey being able to see red in order to find good fruit, to Andrew Smith of Scottland, when Dunn writes an entire passage on how the personal life of Isbell became affected by her desire to prove why the monkeys could see red. It does not mean either author was wrong, but I would favor Dunn’s credibility over the article’s because Dunn does not often propose his opini0ns as facts, and he tends to support his theories with formal citations, as well as with historical anecdotes that only an expert and great researcher could access.
I could be wrong, but my sense from that chapter was that Dunn did not so much buy into the claim that better vision in Old World monkeys was related to fruit. Instead, as my post focuses on, he proposes the snake theory of better vision as a better alternative (that I disagree with). I may have missed something though.
You’re right that he found a few inconsistencies with that particular theory, but he did not go very in depth with it, which is what prompted me to further research it. His main issue to me, seemed to be with the notion that a species (of plant or animal) could impact a separate species’ ability to see color at all (page 175). When I mentioned his “theories” in my post, I should have clarified that these were simply others’ theories he brought up in his novel, not necessarily ones he held true. He seemed to struggle with any of the theories for the reasoning behind their ability to see color, and he did not make many absolute statements on the matter, but the article I attached gave a little more background on that area of research.
It’s not so much that one species is causing another’s vision to change. It’s that a monkey may be more likely to survive if it can see a snake and avoid it. Monkeys that don’t see the snakes are more likely to die.
Are you saying that’s how Dunn viewed it? I was simply stating what I see as Dunn’s key struggle with the theory, my personal views on it aside.