Found this regarding Coyotes and colors.
Dr. Vaughan played a role in this well-known study of color vision in dogs published by J. Neitz, T. Geist, and G.S. Jacobs (1989), "Color vision in the dog", Visual Neuroscience Vol. 3, pages 119-125.
As a result of this study, it was found that dogs indeed lack the same color vision as humans. Humans have three types of color receptors in their eyes. Each color receptor picks up a small portion of the visible light spectrum. Dogs were found to have only two of these three types of color receptors in their eyes. This means that while dogs do see color, they are only able to differentiate a limited number of colors. This is very similar to a human who is colorblind. They are unable to differentiate between certain colors or shades.
Dr. Vaughan summarized the findings of the study by saying,
“These experiments showed that dogs do see color, but in a more limited range than that seen by normal humans, who see the rainbow of colors described by "VIBGYOR": Violet, Indigo, Blue, Green, Yellow, Orange, and Red (plus hundreds of variations on these shades).
Instead, dogs see "VIBYYYR" (Violet, Indigo, Blue, Yellow, Yellow, Yellow, and Red). The colors Green, Yellow, and Orange all look alike to dogs; but look different from Red and different from the various Blues and Purples. Dogs are very good at telling different shades of VIB apart. Finally, Blue-Green looks White to dogs
So, What does this mean to the average hunter? Probably not much since we tend to buy what we feel looks "really cool" as much as what is functional. What this does mean is that we don't necessarily need to be so picky about the exact color of our camo. It is also a great argument in favor of using hunter orange to prevent hunting accidents. Since dogs (and probably deer as well) can't distinguish between orange, green and yellow, you can very easily get away with blaze orange gear because it will blend into all of the other greens and browns in the environment.
As Dr. Vaughan stated, there are more elements to a dogs/coyotes ability to detect a hunter in the wild. While color can play a factor, it is most likely not the most critical factor in going unnoticed in the field. We'll examine those other factors in other articles.