Last week’s column addressed the senses deer use to detect danger: sight, hearing and smell. This time we’ll take a closer look at vision, with a bit more detail on how and what deer see.

As previously noted, deer have larger eyes and larger pupils. That means a larger retina with more and more effective light receptors, and a larger opening that allows more light to reach those receptors. However, the deer’s pupil differs from ours in shape.

Our pupils are round and forward facing, which is likely a result of our position on the food chain as a carnivorous predator. This allows us to see best in a sphere directly in front. The deer’s pupil is more oval or rectangular, which reduces light energy entering the eye from above and below while maximizing light from the horizon, where danger is most likely to occur. Their visual acuity is best along this horizontal plane while their upper and lower peripheral vision is poorer than ours. Having eyes more to the side of their head also affords deer a wider field of view.

Old timers used to say that deer don’t look up. They most certainly do, especially if their blurry peripheral vision picks up movement. They need to in order to bring the image into focus.

Deer don’t see, or at least don’t perceive color the same as we do. They see green wavelengths very well, which only makes sense given that’s a prominent color in their environment. They also see very well in the blue-violet and possibly even ultraviolet (UV) range. This is one of the last color ranges to vanish in the fading light.

Knowing this is important to hunters. Most standard household laundry detergents contain fabric brighteners, which is what gives you whiter whites. They make fabrics highly reflective of light in the blue-violet UV range. It may not make as much difference in bright daylight, but if you wash your hunting clothes in regular detergent, you will literally glow to a deer’s eyes in low light.

If you don’t believe it, take a black light and illuminate your clothes in a dark room. If it glows there, it glows in the woods. And there has been substantial research at the University of Georgia’s deer lab demonstrating deer see very well in this range. Treat your clothes with a UV-killer solution and only wash in hunting soaps and you won’t have a problem, unless you’re wearing blue jeans.

“What about orange?” you ask. Deer don’t see colors in the red-orange end of the visible spectrum nearly as well, and likely see those colors as gray. However, a solid gray shape may still look out of place, but orange camo will help break up the human outline. It’s also worth noting that orange fabric dyes are made in two ways. One is by mixing yellow and red, which should cause no issues. The other is by mixing yellow and violet, and you should be able to see the issue there. It’s less common, but you’ll never know until you hit it with a black light.

As bowhunters know, the best way to break up the human form is with camouflage. Camo companies go to great lengths to develop the most realistic patterns possible. Does it make a difference? Maybe, maybe not, but it does look good on the rack. Some patterns may be so detailed that from a distance you just look like a gray blob, shaped like a human. Better ones have a matrix of larger, light openings mottled with blotches and lines that better obscure your outline. Regardless of what you wear, if you sit still, break up your outline and properly treat and wash your clothes you’ll gain a slight edge.

Bob Humphrey is a freelance writer and Registered Maine Guide who lives in Pownal. He can be reached at: bob@bobhumphrey.com

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