Article on canine vision.

[jcwa]

Can You See Me Now?

I believe that hunters have a specific gene that accounts for many of the manias we suffer. Whether it’s our gun obsession, hand or electronic calls obsession or our obsession with tracking, stalking and taking game animals, I think they can all be attributed to the “Hunter gene”.

This may be the only explanation as to why we spend millions of dollars a year on camouflage clothing, guns and accessories. There’s just something that tickles the hunter gene when we watch someone walk out into the wild, sit down and disappear.

We all experienced it while watching the movie adaptation of Tom Clancy’s book “Clear and Present Danger” You all know the scene I’m talking about. Each of us had one of those “I’ve gotta get me one of those” moments when PFC Chavez popped out of the brush in his ghillie suit a mere 10 feet from the men looking for him.

But when we’re hunting predators, how much camo is too much camo?

There has been a long running debate over the ability of dogs (including foxes and coyotes) to see color. Some hypothesize that dogs can only see in black and white and shades of gray. If that is true, then why isn’t all hunting camo black, white and shades of gray?

The following is taken from an article by Dr. Dana K. Vaughan, Ph.D., from the University of Wisconsin at Oshkosh:

"Vision is just one of several senses that dogs use to scan their world for important information. Any visual scene has multiple aspects to which dogs’ brains are sensitive: brightness, shape, contrast, and motion are a few of these. But what about color?

Many authorities have stated that "dogs are colorblind", with the implication that dogs perceive only black, white, and shades of grey. In fact, this was not known for certain, but became "folklore". Then, in the late 1980s, a definitive set of experiments was done at the University of California, Santa Barbara, by what may well be the world’s foremost research program on comparative color vision.”

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. The complete article may be found by clicking HERE

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.

In the meantime, stay upwind and don't move.

[Doc]

Re: Article on canine vision.

I have often wondered about blaze orange in particular. While various animals may not be able to recognize that color as being different from it's surroundings, I have to wonder about the light reflectivity intensity as a contrast to surroundings. The same thing might be true for any "bright" colors. Might some of these colors stand out just because of their reflective intensity?

I'm sure that an artist could paint a picture that only had greens in it and still highlight an object merely by painting it in a more vivid and intense green in such a way that your eye was immediately drawn to it.

The other question is since color distinction is limited in some animals, do they become more sensitive to shades and hues of the colors that they supposedly can't see. For example, we can look at a black and white photograph and not have any problems picking out the most delicate and insignificant detail. Would animals have any greater problem doing so, or perhaps they may even be more attuned to this kind of vision and be even better at recognizing shape, hues and contrasts.

Just a little more to think about.

Doc

[wtnhunt]

Re: Article on canine vision.

That is very interesting. Sounds very similar to research I have read on deers vision.

Bet like a deer, the canines probably have a much more acute sense of depth and perception at longer distances than we do as well.

[Guest ronin]

Re: Article on canine vision.

I'm familiar with the information but in order to truly validate the experiment relative to hunting it should be, at minimum, conducted on other Canis sp.: lupus, rufus, latrans, etc. It may be that the spectrum and range in nm that the dogs perceive is different with other specieis, sub-species, and hybridization.

The choice of dogs for the test is curious as both can be considered to have extremely good vision. In particular, the greyhound which is known as a sight hound or reliant on it's eyes for it's hunting prowess. Also, both breeds are not known for their scenting abilities. A sense that is crucial for all other Canis sp.,(other than some familiaris breeds), to survive in the wild.

It is known that various breeds of C. familiaris have various levels of sight acuity with range and depth being among the differences. I wonder, too, about color spectrum? Neitz, Geitz and Jacobs account for a very narrow selection of the domestic dog but not their wild cousins.

Not to say that the same might be true for both but I truly wonder. Particularly, in light of numerous experiments and encounters I have had with both sp.

I have never seen a domestic or wild dog pick out a non-moving human based on color alone. The reason was always scent or prominent outline on a visual horizon. The journal does point out that it is unclear the dogs useful capacity for color discrimination. This might be due to the section on intensities and the dogs ignorance of perceived changes.

Good journal, though. I'm glad that you posted it and that I now had a chance to really read it.