Understanding Deer Vision: Why Do They See So Well? - North American Whitetail

Nov 12, 2024

A couple years ago, I was hunting with my friend Barrett on a sunny day with blue skies and high pressure during the heart of the Illinois whitetail rut. He and I were targeting a huge, mainframe 8-pointer that I had encountered a few days prior, and the calm wind and weather made for ideal conditions to tag-team the buck.

We were in separate stands, both on different ridges in the timber, but still within 100 yards of one another. Barrett messaged me and said that I stuck out like a sore thumb. This was because I was wearing a very trendy set of outerwear that didn’t blend in with the foliage around me, especially in the bright sunshine.

An hour before sunset, I heard the unmistakable dry leaf crunching cadence of a buck headed my way from the east side of the ridge; and then I saw the buck. Target acquired!

He was in a zombie-like rut state headed right to the base of my tree. I positioned my video camera, hit the record button and prepared for a very tight encounter. I came to full draw well before the buck got to nine yards where the animal abruptly stopped, snapped out of his testosterone induced stupor and jerked his head up to look right at me.

The quartering-to angle made selecting my shot placement tricky, but I had confidence in my fixed blade broadhead and arrow combo. With him looking me dead in the eye, I picked my spot and let it rip. The buck bounded away and only made it 100 yards before toppling over.

I sat there wondering what had just happened! I wasn’t moving, and the buck certainly didn’t smell me because there was no wind blowing in his direction. The stand didn’t squeak, and I was ultra-silent during the encounter. Then it hit me that Barrett was right: I stuck out like a sore thumb! And that big buck clearly saw me 24 feet high in the treetops. His vision and my inability to blend in almost cost me the biggest 8-pointer of my life.

As an 18-year veterinarian, I took great interest in learning more about how a deer views his environment after my encounter with the big 8-point. Let us examine just how the cervid eye works on an anatomical level.

For vision to occur, there must be a cascade of light transmission from the animal’s environment to the brain. Light first meets the cornea, which is the physical outer globe of the eye, and then travels to the iris and pupil. The iris is the yellowish/tan colored ring that surrounds the circular black pupil in the center. These structures act together to regulate the amount of light allowed through the lens and ultimately the retina. The lens of the eye acts on light to focus it into the retina where specialized cells (called photoreceptors) convert light into electrical impulses. These signals rapidly travel through the optic nerve to the brain for interpretation of an image.

To this point, the visual circuit of the whitetail doesn’t appear to be much different than ours, but the animal has several unique adaptations and anatomical variances that contribute to the visual process.

The white-tailed deer is a prey species, and we are not! Therefore, the vast majority of a deer’s senses are designed to do one thing: survive predation. With this in mind, consider the positioning of the eyes on a mature buck. His eyes are on the side of his head and his field of vision is a whopping 310 degrees, which gives him a tremendous field of view to detect danger.

A deer’s eye position can be independently controlled to better see the horizon line for this reason, a phenomenon called cyclovergence. When a deer’s head goes into a feeding position, the eyes will align themselves vertically and horizontally to give the animal a level view of the surrounding area and binocular overlap of both eyes in front of the head.

Perhaps the most telling anatomical adaptation of deer vision is the whitetail’s ability to perceive low light. In the back of the eye, along a horizontal band of tissue in the retina, specialized cells called photoreceptors can be found. There are two basic types of photoreceptors: rods and cones. These cells occur in unusual numbers when compared to human anatomy. I spoke with the University of Georgia’s Dr. Gino D’Angelo about this.

“Whitetails have a tremendous number of rods compared to cones,” Dr. D’Angelo says. “Rods are photoreceptors that are much more sensitive to light than to color, where cones are used for color vision and visual sharpness. A whitetail’s visual acuity is around 20/60 where ours is 20/20, meaning they see the world three times less clearly than we do. What the animal has is very similar to red-green color blindness in humans with poor clarity at distance.”

Looking at the crepuscular nature of deer, their vision makes them very capable of seeing in dusk and dawn hours. Have you ever been sitting in a tree stand on an overcast morning and noticed how “blue” the light appears to be at dawn? The structure of the rods and cones in a deer’s eye allows the animal to see extremely well during this time of day. Furthermore, deer have a shiny membrane at the back of the eye called the tapetum lucidum. Ever notice the shine to a deer’s eye after dark in your headlights? The tapetum lucidum serves as a light reflector, forcing available ambient light to the photoreceptors of the retina. The combination of blue light sensitive rods and the tapetum make for an animal with crepuscular tendencies.

It appears a deer’s visual capabilities are much worse than our own on many levels. However, one thing a whitetail can see is ultra-violet light. Light is in a physical wavelength spectrum, and I learned the saying ROY G. BIV when I was in physics class in college, which means Red-Orange-Yellow-Green-Blue-Indigo-Violet in decreasing wavelengths. Due to the structures of rods in the retina, deer perceive the world like a color-blind person. Dr. D’Angelo notes that the shorter the wavelength, the better a deer can interpret that color. Although the animal may not see blaze orange or red plaid well, blue jeans are another story.

With the ability to see into the UV spectrum of blue light, deer are much more likely to travel by twilight or under the cover of a full moon.

If I’m being objective, a whitetail’s eyesight is much easier to trick than their nose; and in my opinion, as a prey species, they use their eyesight to confirm the dangers noted by their nose. Because of this, there are several rules of thumb I adhere to so I stay hidden in hunting scenarios.

Go Early, Stay Late: When hiking to and from tree stand locations, I like to use the darkness to my advantage. Though a deer’s night vision is not infinite, it is certainly better than mine; however, their ability to see in the blueish hues of dawn and dusk is second to none. When it comes to entering or exiting the woods, the less available ambient light the better.

Avoid the Open: I hunt a lot of open prairie ground here in the Midwest, and I have spooked hundreds of deer off feeding fields over the years. Access routes to and from hunt sites should be selected to avoid open country contact with feeding deer during their crepuscular activities.

Cover is King: When selecting a tree stand location, height is less important than cover to conceal your movements. A deer’s eyesight may not be acute, but it is adapted at seeing movements along a lateral plane. So both front and back cover need to be considered for optimal concealment when drawing a bow or raising a firearm.

Blend: Though a deer’s color vision is poor, it is still beneficial for hunters to color match their hunting area. And you need to be prepared for this to possibly change from hunt to hunt. An outerwear color scheme fit for the skyline may not blend as well deep in the hardwoods or on the ground in natural cover. Likewise, I try to avoid blacks for grays and browns, and I usually keep my backpack on my tow rope to reduce my profile in the tree.

No Glow: Want a wake-up call? Buy a good quality black light and look at your outerwear in a dark room. A lot of today’s outerwear are printed with inks that shine like a diamond under a black light, and this could be interpreted as UV-light to a deer’s eye. I have tried UV-killer detergents with mild success depending on the garments to mitigate this. Natural fibers like wool or wool blends of brown or drab green seem to perform better under the black light.

So, what happened in the hardwood timber that day when the biggest 8-pointer of my life picked me off at point-blank range? I’ll tell on myself here and admit that I did just about everything wrong in terms of beating the buck’s eyesight. My choice of outerwear was a blueish-gray pattern meant for a skyline, and its color was wholly out of place in the reds and browns of the timber. My tree stand was high, roughly 25 feet, but it had no front cover and minimal back cover. The sunset was bright and over my shoulder from the buck, and I probably glowed like a stoplight up there above him. The subtle movement of full draw caught his eye, and I was extremely lucky to tag the animal. The only thing I did right in that situation was making a great shot!