Deer have a very different visual system compared to humans. Their eyes are located on the sides of their head, giving them a wide field of view. This allows them to easily detect movement and spot predators. However, it also means they have poor depth perception. Let’s take a closer look at how deer see the world.
The structure of a deer’s eye
Like humans, deer have two eyes. But there are some key differences in the structure:
| Human eye | Deer eye |
| Forward facing | On the sides of the head |
| Good depth perception | Poor depth perception |
| Higher concentration of cones | Higher concentration of rods |
| Three types of color cones | Two types of color cones |
Having eyes on the sides gives deer a field of view of around 310 degrees. They can easily spot movement behind or beside them. Humans have a field of view of around 180 degrees.
Deer also have a higher concentration of rod cells compared to humans. Rods detect motion and work well in low light conditions. This allows deer to see well at night.
Humans have more cone cells which detect color. We have three types of cones that allow us to see red, green and blue light. Deer only have two types of cones, so they can’t distinguish red and green hues.
What colors can deer see?
As mentioned above, deer have two types of cone cells in their eyes that allow them to detect some colors:
– Blue cones detect short wavelength blue and ultraviolet light
– Yellow/green cones detect middle-to-long wavelength green, yellow and orange light
This means deer can distinguish between blue, purple, green, yellow, orange and brown colors. However, reds, pinks, greens and oranges may appear as shades of yellow.
So while deer don’t see the full spectrum of color like humans, they do have some color vision. This helps them find food and detect predators.
Deer vision in daylight
During the daytime, deer rely more on their cone cells and color vision. Their eyes adapt to brighter light in order to pick out details and movements.
A deer’s daytime vision is actually thought to be quite good. Their visual acuity is similar to a human with 20/40 vision. This means they can’t see quite as sharp at a distance as humans, but their vision would still be considered normal.
Deer use their daytime color vision to:
– Locate reddish-brown fur of other deer against green foliage
– Spot the orange and white markings of fawns
– Detect blue denim and other unnatural colors that could indicate a human presence
However, deer do have a few blind spots due to their wide angle vision. There are blind areas directly in front and behind them. So they may not detect motionless predators like crouched hunters in these spots.
Deer vision at night
Deer are crepuscular, meaning they are most active at dawn and dusk. But they also spend a lot of time moving and feeding at night.
In low light, a special layer of cells in their eyes called the tapetum lucidum reflects light back through the retina. This allows the rods another chance to detect the light signal.
The tapetum lucidum is what makes deer and other animals’ eyes appear to “glow” at night when light shines on them. It’s an adaptation to help them see in darkness.
At night, deer vision relies almost entirely on the rod cells. While they can’t distinguish colors very well, the rods allow them to detect shape, movement and light contrasts. Their night vision is actually thought to be around 5-6 times better than humans.
So deer can navigate through forests, spot predators and forage in very low light conditions. Their vision is optimized for the crepuscular periods when they are most active.
Other adaptations for deer vision
Along with the specialized structure of their eyes, deer have other adaptations that aid their vision:
– Wide placement of the eyes – As mentioned, this gives deer a wide field of view to easily spot predators.
– Vertical slit pupils – The rectangular pupils allow precise control over how much light enters the eyes. This helps in both bright and dim conditions.
– Brows and lashes – Deer have pronounced brows and long eyelashes. These help shade their eyes from harsh sunlight and improve vision.
– Speedy eye movement – Deer can quickly scan their surroundings by moving their eyes without turning their heads.
– Swiveling ears – Deer continuously swivel their ears to pick up the smallest sounds and pinpoint the source. This complements their wide field of view.
How deer use their vision when interacting with humans
A deer’s vision has important implications in how the animal perceives and interacts with humans. Here are some key points:
– Deer can easily detect human movement even in peripheral vision. Sudden movements will alert them.
– Unnatural colors like bright orange may startle them, while camouflage can help hunters avoid detection.
– At night, deer can likely see vehicle headlights from a significant distance away due to their excellent night vision.
– Deer have trouble seeing humans who remain motionless. Their narrow focus and blind spots means still hunters can avoid being spotted.
– Objects directly in front or behind a deer fall in its blind area. Hunters should avoid these positions.
– Deer likely can’t read signs or decipher human facial expressions due to lower visual acuity and color limitations.
Understanding exactly what deer can and can’t see helps hunters be more successful, wildlife photographers get better shots, and drivers reduce deer collisions.
Conclusion
The key takeaways about deer vision include:
– Widespread placement of the eyes gives them a wide 310 degree field of view to spot predators
– More rod cells allow excellent night vision, but fewer cone cells limit color distinction
– Deer see blue, purple, green, yellow, orange and brown, but reds and greens appear dull
– Daytime vision adapted to see details, movement and some colors
– Tapetum lucidum enables great night vision by reflecting light back through the eyes
– Other adaptations like elongated pupils, eyelashes, ear swiveling and neck flexibility aid vision
– Deer can detect humans easily through movement, but have difficulty seeing motionless hunters
– Limitations like lower visual acuity and narrow focus create some blind spots deer hunters can exploit
So while deer have some visual disadvantages compared to humans, their specialized eyes allow them to thrive as prey animals that are most active in crepuscular periods. Their vision equips them perfectly for detecting predators, foraging at night, communicating through body language and navigating their environment safely.
Frequently Asked Questions
How good is a deer’s sense of smell compared to its vision?
A deer’s sense of smell is thought to be much more important for survival than its vision. Their eyes are a secondary sense compared to their ability to detect scents. Deer likely depend more on smell than sight for activities like detecting predators, finding food sources and communicating.
Can deer see as far as humans?
No, deer have lower visual acuity than humans, meaning they cannot see fine details as sharply from a distance. A deer with 20/40 vision would be considered to have normal vision, but a human with 20/40 vision would be moderately near-sighted.
How well can deer see at night versus day?
Deer see around 5-6 times better at night than humans due to a high concentration of rod cells and the tapetum lucidum. During the day their vision is adapted more for seeing colors and details, albeit with some limitations on visual acuity.
What colors can deer not see?
Due to only having two types of cone cells, deer cannot distinguish between reds and greens. These colors likely appear as shades of yellow or brown to a deer. They also can’t see pure pinks or dark greens the way a human would.
Do deer have good depth perception?
No, since deer have eyes on the sides of their heads, they have poor depth perception compared to animals like humans that have forward facing eyes. This impacts their ability to accurately judge distances.
Can deer see UV light?
Yes, deer can see into the ultraviolet spectrum due to their blue cone cells that detect short wavelengths of light. This may help them spot urine and other cues not visible to humans. Many birds and insects also see UV light.
Why do deer look directly at an approaching car at night?
Deer likely stare at oncoming headlights because the brightness overwhelms their vision. This can cause them to freeze up instead of fleeing the roadway. Drivers should slow down and sound the horn to encourage the deer to move.
Can deer see orange clothing?
Yes, deer have cone cells that detect medium to long wavelength light, so they can distinguish the color orange. In fact, the high visibility of orange gear compared to natural colors may startle them or make them raise their heads.
How can hunters use knowledge of deer vision to their advantage?
Hunters should wear camouflage instead of bright colors to avoid detection. Moving slowly and stopping frequently helps avoid attracting attention through movement. Staying out of a deer’s forward and backward blind spots also helps. Calling on a deer’s limited color vision, orange can be used to track blood trails.
