Deer have amazing eyesight with some exceptions

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As prey animals, deer are well equipped to detect and avoid predators, and one of their primary tools of defense is their vision. As such, deer hunters can be more successful when they understand the strengths and weaknesses of deer eyes, according to the National Deer Association who bases this information on research from University of Georgia Deer Lab. 

Here are some interesting facts derived from this research with the first one being the 20/60 factor. As many successful hunters know, deer eyes have pupils that are wide, horizontal slits. This shape allows them to let in more light than human pupils can, especially as they open wider in low-light. It’s important for them to detect movement across a wide, horizontal view where danger is most likely to appear. While this pupil shape helps them monitor a broader area, they sacrifice sharpness. Normal human eyesight is 20/20 whereas deer have a normal daylight eyesight of about 20/60. This means they see three times less clearly than humans. If you make eye contact with a deer for what felt like an eternity, it’s likely because they’re trying to figure out exactly what they’re looking at. 

With the 20x factor, deer and humans have photoreceptors in their eyes called rods and cones. Rods are responsible for light absorption and are what animals use to see in low light, while cones are responsible for color vision and distinguishing fine details. Deer have fewer cones but more rods than humans. Thus, deer see better in low light than we do, but they see with less clarity. 

The Blue factor takes in the question can deer see blaze orange? The short answer is no, not in the same way humans see it. Deer see oranges and reds as brown or gray. This is the reason deer have a distinct advantage when moving to and from cover. Therefore, deer can see blue nearly 20 times better than humans so don’t wear blue jeans when going hunting. 

The 18x factor shows that deer have a layer in the back of their eyes that act as a mirror. Any light that is not absorbed when it first enters the eye is reflected back across the rods. This allows deer to use the same light twice, while humans only get to use it once. But the shape and location of this reflective layer is adapted to  light coming from the horizon, which is strongest at dawn and dusk. Contrary to popular belief, deer are not nocturnal. However, they see about 18 times better at twilight than we do. 

As for the 4x factor, and even though deer have lower image sharpness, deer receive and process images nearly four times faster than humans at dawn and dusk. This means they are extremely good at detecting even the slightest movement in their visual field. It’s almost like they perceive the world around them in slow motion. So, distorted patterns in camo can help you blend into your surroundings due to a deer’s poor visual acuity – but only as long as you remain still. 

And lastly, the 300-degree rule points out that because deer eyes are positioned to the side of the head, deer have a large field of vision which is about 300 degrees, leaving only a 60-degree blind spot in the back of the head. So, unless you are directly behind a deer, they can see you. Humans only have a 180-degree field of view, but we have greater binocular overlap, which also helps with focus. Deer sacrifice clarity and focus for the ability to detect danger in almost every direction at once. Even if deer have their heads to the ground to feed, their pupils align with the horizon and maintain a wide field of view although their nose is pointed downward. They can still see you move. 

Hope these deer vision facts provide some insight to a deer’s good vision. 
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