Part 1 of 3 parts on the deer’s eyes, ears and noses
Every day as wildlife participates in a battle between predator and prey, each side has its advantages. Predators have eyes on the front of their heads to give them an offensive advantage. Front-facing eyes give better visual depth perception, enabling an animal’s brain to calculate speed and distance so he can strike at the most optimum instant.
Next time you see a picture of a coyote, note that its eyes face forward. Now that you know why, take note that your own eyes are also on the front of your head. You’re built to be a predator too.
Eyes on the front of your head have limitations. Despite what you and your siblings thought about your mother and regardless of the rumors about what a few of your schoolteachers were able to do, they did not really have eyes on the backs of their heads.
Unlike coyotes and distinct from humans, deer have eyes on the sides of their heads (much closer to the back of the head). Your front-facing eyes give you better depth perception than a deer has, but a deer’s side-eyes allow him to see more of what’s behind him, a clear defensive advantage.
To put this into simple mathematical and geometrical terms, your field of view (thinking of yourself at the center of a circle and using both eyes) is about a third of the circle, or 120 degrees. Your peripheral vision (the area you can see with each eye individually) adds about 20 degrees on each side. So your total field of view is about 160 degrees. That’s where a deer has you and me beat, by a lot, because two-thirds of our circle (240 degrees) is in our “blind spot.”
A deer, with eyes positioned on the sides of its head, has a much greater field of view, about 310 degrees. That’s more than 85% of a circle. With a field of view more than double that of his predators, his blind spot is only 50 degrees of the circle. The better to see you with, my deer!
One weakness of the deer’s eyes is that he doesn’t have the precision binocular-like focus that humans have. We see with the greatest resolution when we use both eyes, putting the object of our vision in the center of our retinas. The deer can’t do that with both eyes at the same time.
That means the deer can’t identify everything he sees as quickly as we can. Instead, he notices movement, or something out of place. Then he brings his other receptors into play to do the fine-tuning. He applies both eyes to the task, he rotates his ears to pick up any telltale sounds, and he employs his nose. When his eyes and ears can’t be certain about a threat, his nose will establish danger beyond doubt. It will tell him if he needs to skedaddle.
What does this mean for the still-hunter, oozing through the woods at a cold snail’s pace? Your advantage is that a deer can’t always identify what it sees.
Although we can’t get away with a lot of movement, we can get away with some. So, walk very slowly. Spend more time standing still than walking. Stop beside trees to break up your outline and to serve as a rifle rest if you need to shoot. Don’t exaggerate your horizontal movements by reaching out to touch a tree or by bending at the waist. Use binoculars to see farther ahead.
To get a better perspective, you may want to back up slowly rather than move sideways or forward. Study everything you see, looking for parts of a deer, the twitch of an ear, or the horizontal line of his back. See him not necessarily before he sees you, but before he knows what you are.
A deer’s eyes are large, but that doesn’t mean his vision is better than yours. In general, it isn’t. In daylight when you have your best vision, he might have his worst, so capitalize on the visual advantage you have.
When “The Everyday Hunter” isn’t hunting, he’s thinking about hunting, talking about hunting, dreaming about hunting, writing about hunting, or wishing he were hunting. If you want to tell Steve exactly where your favorite hunting spot is, contact him through his website, www.EverydayHunter.com. He is a field contributor to Deer and Deer Hunting magazine, and won the 2015 and 2018 national “Pinnacle Award” for outdoor writing.