Insight on Eyesight

By Josh FletcherOctober 28, 20103 Comments

LAST UPDATED: May 8th, 2015

  I feel that to be successful at consistently taking an animal each year, you need to know about that animal. Most articles that you read are about scents or hunting tactics, but often overlooked are articles about the particular animal. How does an animal actually use their sense of smell? How does odor work? How do they see? What do they see? I think it is ironic that we as hunters spend millions of dollars each year on the latest and greatest camouflage patterns on the market that are manufactured to please the human eye and not hide us from a deer’s vision, the exact purpose of camouflage.  In fact with so many manufacturers and styles we now treat it like a fashion show.   The real issue is what camouflage pattern is most effective to fool the deer’s eyes?
  Last year I wrote an article on scents and scent elimination. I now want to take time and cover the topic of how a whitetail’s vision differs from ours. In this article I will cover the information on how we as humans see the world versus how deer and other animals see the world around us. I will also cover topics such as Ultra Violet (UV) and UV brighteners in hunting clothes and how this affects the camouflage patterns, and which camouflage pattern works best to fool a deer’s eyes, not the hunter’s.
  First to be able to understand and picture how a deer sees the world, we need to understand how our eyes work and why we see what we do. By understanding how you see will help the hunter better picture the world that a deer sees.  Use of this knowledge will assist in picking the right camouflage pattern, right back ground in a tree, and even when to move and when not to move while in the stand.

Understanding how a deer sees makes you a better hunter an can ultimately help you score on bigger bucks.

 To start off with, in the retina, located in the back of the eye, consists of two types of light sensitive cells called rods and cones. These cells collect light that the brain perceives as vision. Now the simple version is that rods are for night time or low light vision and cones are for color and daytime vision.  The hunter’s eye consists of three types of cones. One is for short wavelength light (blue), consisting of approximately 10% of our cones.  The second is for middle wavelength light (green), the second most common cone in our eyes.  And the third is for long wavelength light (red), the most common cone in our hunting eyes. Having these three cones is called Tri-chromatic vision. By having Tri-chromatic vision allows us to see a broad spectrum of color, everything from blue to red.  Hunters see the green-yellow spectrum of color the best out of the three different cones.  Humans also have a UV (Ultra Violet) filter in our eyes. This protects our eyes from the sun’s damaging UV rays. This UV filter also allows a clearer and crisper vision. This is also the reason most target shooters wear amber or yellow colored shooting glasses. This allows us as hunters to see fine objects and read fine print. The down side of this filter is that it lessens our sensitivity to short wave length colors (blue) and does not allow us to see UV. If we did not have this UV filter it would cause the short wavelength light to blur the image. We as humans use the center of our retina the majority of the time to look at an object. This area of our eye is full of cones and no rods; the rest of our eye consists of rods and cones. This allows us great detail and color and very poor night vision. Also we are predators. Our eyes are positioned at the front of our head similar to other predators such as bears, foxes and wolves. Prey animals such as deer have eyes on the side of their heads giving them a broader field of view. If you think about it, as a predator we lock on to our prey and focus on the animal. A prey animal is constantly scanning, looking for danger as it goes about its day.  As a hunter we see a broad range of color under a bright lighting condition, however because we are able to see such a broad range of color, our eye used up the majority of its room on cones, and we have less rods. By having fewer rods, causes us to have poor vision under low light condition.
  Now that we have an idea of how our eyes work, let’s take a look at a deer’s eye and how it differs from ours.  Knowing that we humans have almost all cones in the central part of our retina, and a low number of rods in the remainder of our retina allows us to see a greater spectrum of color. A deer’s eye consists of more than 90% rods giving deer excellent night vision. By having more rods than cones a deer can see more detail in low light than it can during bright light. Humans have three types of cones (Tri-chromatic vision) but deer only have two types of cones (Di-chromatic vision) The two cones they have are short wavelength light (blue) and middle wavelength light (green). Deer do not possess the long wavelength cones, so they cannot see reds, oranges, browns, and most shades of greens. These colors can be seen by deer, however, are perceived differently than we see them. They are most often perceived as different shades of yellow because they don’t have the long wavelength cone. A deer’s most sensitive vision is that of short wavelengths (blue) and they do not have the UV filter that humans do. This allows deer to see the blue spectrum much better than we do. They can also see UV while we cannot. However, by not having the UV filter, their vision is slightly blurred and thus not as crisp as ours under good lighting conditions. Because deer are prey animals their eyes are on the side of their head, giving them a much larger field of view, also since they don’t focus on an object like we do, they have better peripheral vision allowing them to pick up movement much faster and better than we can. Just because they have a blurred vision during day light doesn’t mean you will get away with movement much easier. Also deer can see better in low light conditions than they can under bright lighting conditions, which is the exact opposite of that of a human.

My 2009 buck.  Knownig which camouflage pattern to use during the right situation is a subtle hint that can tip the odds in your favor.

  Now looking at the central region off the eye in a human, we posses all cones for great color vision. In a deer’s central region of the eye, they posses both rods and cones and rods are about one thousand times more sensitive to light than cones and deer have a higher ratio of rods to cones giving them a great night vision. So we now know that deer can see better at night but lack the ability to see the long wavelength  colors such as reds and oranges, however they can see short wavelength color better than we can which is blues, violets, and UV.  We now know that they have a better vision under lowlight than they do during the day time. So how can they see much better at night and what does their night vision look like to them? First off, a deer is designed for low light conditions which would make sense because that is when they are most active.  A deer’s eye is all about light gathering. They have a reflective membrane on their eye called a tapetum. A tapetum reflects the light not absorbed by the receptors on its first pass to be absorbed a second time, basically recycling the non used light. The tapetum is what causes the deer’s eyes to shine under a light at night. A deer’s pupil can also open much larger than ours can also allowing more light to reach the retina, and the fact that a deer’s eye is 90% rods. The use of rods in a deer’s vision under low lighting conditions causes the deer to see in shades of black and white when the lighting conditions are too low for cones to work; essentially a deer’s night vision consists of the black and white color spectrum.

Deer see far better than we do at night, however, their vision is at it’s best during low light conditions.  Namely, dawn and dusk.

  Now that we have a better understanding on how deer see the world around them, what does this mean to the hunter?  First off we need to start paying attention to UV and UV brighteners that are in our hunting cloths. So what are UV brighteners? They are what cause your “whites to be whiter and your brights to be brighter.” UV brighteners gather light from a wide range of wavelengths and reflect the light in a strong band that is best seen by deer from their short wavelength cones and rods, also they do not have a UV filter on their eye like we humans do. Most fabrics that are used to make cloths are dyed with UV brighteners; this makes the color on the fabric look much brighter and crisper to the human eye. When camouflage companies buy their fabric to be printed and made into hunting cloths they want the fabrics to be UV brightened. This makes their camouflage pattern look brighter, crisper, and better to the human eye. Essentially most camouflage companies are trying to fool the human eye and not the deer’s eyes. This can cause the exact opposite affect that we the hunter want our camouflage to do for us. Because the UV light spectrum appears to be a glowing blue to a deer or an animal without the UV filter on their eye, making you look like a radioactive smurf sitting in a tree, versus blending in with your surroundings. To avoid this you have several different options.  The first is that there is a company that makes a UV inhibitor that eliminates UV from reflecting off of your clothes.  You spray the UV inhibitor on your cloths and allow it to soak in and dry prior to hunting.  Second option is use natural wool clothing. The old time hunters have used wool forever and swear by its warmth, they just weren’t aware of an additional benefit was that natural wool does not contain UV brighteners.  You can also look for camouflage fabrics on the market that say on their tag that they do not contain UV brighteners and dyes. When it comes time to wash your cloths make sure that the soap that you use for your hunting cloths is not the same for everyday laundry. Number one reason is the scent and number two reason is because they all contain UV brighteners. Use soap designed for hunting cloths that say right on the bottle that it does not contain UV brighteners.

Deer are grazers and because of this, their eyes are positioned on the side of their head to better scan for predators while feeding.

  Now that we understand the importance of not glowing like a radioactive smurf, let’s talk about choosing a camouflage pattern. We know that deer can see shades of blue much better than we can so wearing blue jeans is out of the question if you don’t want to get spotted by a deer.  I feel that matching your camouflage shade is much more important when picking out camouflage. For example, if you hunt a darker area such as pine trees or evergreens you will want a darker color shade of camouflage.  If you hunt open hardwoods during the rut you will want a much lighter shade of camouflage. Modern camouflage companies are catching on to this and are marketing camouflage patterns designed for tree stand hunting and open sage country. One company is Sitka; I just saw a recent ad in a magazine for their camouflage.  Their design is based on how deer see. I have never used this camouflage or seen it in person but it does spark my interest.
Whichever camouflage pattern you choose is up to you, however if you really want your camouflage to be effective and more than just a fashion statement, you will want to make sure you do the following: eliminate any UV brighteners,  match the shade of the background you plan on hunting and make sure it breaks up your outline. If you have ever been spotted by a deer and wondered how they saw you, chances are it was one or all of these things that caused the deer to see you even if you thought you were well hidden.
Hopefully in this article I was able to provide you with information on how we see the world versus how deer see the world, and that this information will help you better blend into your surroundings this fall. After all a big old buck sometime seem impossible to get a shot at, and we need as much to our advantage we can get. Until next time I’ll keep you posted.

Josh Fletcher
    Post a Comment View 3 Comments
    Want to win a Pulsar Axion Thermal Imaging Scope?
    Pulsar Cam.png

    On July 23rd, we’re giving away a FREE Axion XM38 unit to 1 lucky winner!