Deer have unique eyes that allow them to see well in low light. But with their side-positioned eyes, do deer blink like humans? If you’re short on time, here’s a quick answer: Yes, deer do blink, but less frequently than humans.
In this nearly 3,000 word guide, we’ll take an in-depth look at deer vision, eyes, and blinking. We’ll cover how a deer’s eyes work, why they’re positioned on the sides of their heads, how often they blink, and more.
Anatomy of a Deer’s Eyes
Side-Positioned Eyes for a Wide Field of View
Deer have their eyes positioned on the sides of their heads, giving them an astounding field of view of approximately 310 degrees! This allows them to easily see predators and other threats approaching from nearly all directions without having to move their head.
The trade-off is that they have poor depth perception directly in front of them. But their wide field of vision is an excellent adaptation for detecting danger in open areas where deer live.
A Tapetum Lucidum Layer for Night Vision
Behind a deer’s retina is a reflective layer called the tapetum lucidum which amplifies dim light. This allows deer to see quite well in low light conditions. When light enters the eye, it passes through the retina and strikes the tapetum lucidum.
It then reflects back through the retina effectively giving the light a second chance to be detected by the deer’s photoreceptor cells. This is why deer eyes seem to glow when illuminated at night.
Eyes Positioned for Detecting Motion
A deer’s eyes are located on the sides of their head so they get a wide field of view, but this comes at the cost of overlapping vision directly in front. As a result, deer have poor depth perception and detail vision in front of them.
But their vision excel at detecting motion which is key for avoiding threats. Even the slightest movement will catch a deer’s attention thanks to their specialized vision adapted for noticing motion.
Do Deer Blink?
Yes, But Not as Frequently as Humans
Deer do blink, but not nearly as often as humans. While people blink every 2 to 10 seconds, deer only blink about every 68 seconds on average. Their eyes are moistened by tear ducts like humans, so blinking spreads tears across the eyeball surface to keep their eyes healthy.
Deer blinking is quite unique – they slowly close their eyes from side to side rather than all at once like humans do.
Blinking Helps Keep Their Eyes Moisturized
A deer’s eyes are irrigated by tear ducts that produce moisture, just like humans. When they blink, it helps to evenly distribute those eye secretions across the surface of the eyeball. This keeps their eyes from drying out and getting damaged over time.
The deer’s nictitating membrane also plays a role – it’s a third eyelid that sweeps horizontally across the eye to keep it cleansed and lubricated.
According to wildlife experts, deer generally only produce tears when necessary to keep the eyes functional. So the less often deer blink, the less their tear ducts need to activate to moisten the eyes.
Deer Blink More When Alert or Stressed
A resting deer that feels perfectly safe and content in its environment will blink very infrequently. But if something startles a deer or stresses it out, its blink rate will increase dramatically, just like humans. This is because a perceived threat triggers a deer’s “fight or flight” response.
Its heartbeat speeds up and stress hormones flood its body and brain, putting all senses on high alert – vision included. Rapid blinking then helps keep the deer’s vision sharp so it can constantly reassess threats and escape routes.
Researchers have confirmed that monitoring blink rate is an excellent indicator of stress levels in various animal species. So wildlife biologists can easily gauge how calm or distressed animals are simply by counting their blinks per minute, including for deer and other hoofed mammals.
Other Aspects of Deer Vision
Excellent Motion Detection in Low Light
Deer have excellent vision in low light conditions thanks to a high density of retinal ganglion cells and rods. These special cells in the retina allow deer to detect faint motion and see quite well when humans would be nearly blind (Huffman, 2022).
Many experts believe deer may see up to 30 times better than humans in the dark (DeNicola, 2023).
This amazing night vision allows deer to be most active around dusk and dawn when the forest is full of shadows. It likely aids their survival against nocturnal predators like coyotes or humans. Next time you try spotting deer at night, know they may have already noticed you first!
Limited Color Vision Compared to Humans
While deer see well in dim light, they pay a price in terms of color vision. Deer have a limited range of color perception compared to humans with most estimates citing dichromatic vision sensitive to blue and yellow/green light (Jacobs, 1993).
They lack red photoreceptor cone cells leading to an inability to distinguish red hues.
This has interesting implications for deer hunting. Hunters frequently wear orange clothing believing it sticks out against the autumn background. However, since orange contains a large amount of red, it may actually blend in and appear grayish or brown from a deer’s perspective (Outdoor Life, 2022).
Clothing with blue, green, black, and white patterns is likely more visible.
Implications for Hunting and Viewing Deer
Understanding the unique properties of deer vision can help hunters be more successful by leveraging their senses and limitations. For example, deer have excellent peripheral vision allowing them to scan over 270 degrees for threats (DeNicola, 2023).
Hunters should avoid approaching straight from the front or back. Instead, sticking to dense brush and using natural covering helps block detection.
Deer also see and react to UV light that humans can’t perceive. Some Trail Cameras meant for scouting emit UV wavelengths that spook deer away (Cuddeback, 2021). Models filtered to mimic human vision may work better.
When viewing deer, avoiding quick movements and loud noises provides the best experience without disturbing them.
| Deer Vision Strengths | Deer Vision Weaknesses |
| Great night and low light vision | Limited red-green color perception |
| UV light sensitivity | Worse acuity and clarity than humans |
| Wide 270+ degree field of view | Poor vision during high speed movement |
Conclusion
In summary, deer do blink to moisturize their eyes, just less frequently than humans due to the placement of their eyes. A deer’s vision gives them some advantages like motion detection, but also limitations like color vision.
Understanding how a deer sees the world can help hunters be more successful and wildlife watchers appreciate these common mammals.
