When dogs look up at us with those big, soulful eyes, they are pretty irresistible. It’s easy to assume that what they see when they look at the world is the same as what we see. But actually, dog vision isn’t the same as human vision. If that’s the case, then can dogs see in the dark?
Dogs see fewer colors than most humans (yellows and blues) and recognize objects only at much shorter distances (maybe that’s why your own dog barks at you when you’re in the driveway). Dogs’ depth perception is poorer than human depth perception. However, when it comes to seeing in the dark, dogs definitely have us beat.
Understanding Dog Vision
- Visual perspective
- Field of view
- Depth perception
- Sharpness of vision (Dogs typically have 20/75 vision.)
- Perception of color and form
- Ability to perceive light and motion
Understanding dog vision starts with understanding our pets’ evolution from wild canines. Wild canines were crepuscular, derived from the Latin word for twilight, meaning they were active primarily at dusk and dawn. They needed to be able to spot movement in the dim light in order to track and catch their dinner or breakfast. As dogs evolved, they retained this advantage to see in the dark, while adapting to function in broad daylight.
The Structure of the Canine Eye
When you take your dog out at night, do you ever notice how they alert to objects more quickly than you do? Obviously, their stronger sense of smell is useful, but it’s also because dogs can see movement and light in the dark (and other low-light situations) better than humans can.
They are assisted by the high number of light-sensitive rods within the retina of their eyes. Rods gather dim light, which enables better night vision. In contrast, the human retina is dominated by cones that detect color and function in daylight.
How can dogs see in the dark? Their secret weapon is the part of the canine eye called the tapetum lucidum. The tapetum is a special layer of reflective cells behind the retina that acts as a mirror within the eye, reflecting the light that enters it and giving the retina another opportunity to register that light. This magnifies and enhances visual sensitivity under low light conditions and increases the dog’s ability to detect objects. Human eyes don’t have the tapetum.
An animal’s ability to see in the dark is also influenced by Critical Flicker-Fusion Frequency (CFF), also known as Flicker Fusion Frequency (FFF). This is the rate at which an animal understands flickering light to be a constant image. Generally speaking, the faster a species moves through its environment, the higher its CFF or FFF. “Dogs have a higher flicker fusion threshold than humans, so a television screen that appears to show continuous motion to humans might appear to flicker to a dog, while this sharpened ability to see flickering light allows the dog to detect slighter movements in the dark,” says Dr. Jerry Klein, Chief Veterinary Officer for the AKC.
Most dogs, depending on breed, have eyes located more on the sides of their heads than humans do. This also gives them a wider range of view than humans, allowing them to scan their environment more quickly.
Why Do Dogs’ Eyes Glow in the Dark?
You’ve no doubt seen that eerie, greenish-yellow glowing look of a dog’s eyes when light hits them at night from headlights or a flashlight, and in photos (caused by the camera flash). What you’re seeing comes from the tapetum.
The color of the tapetum as it reflects light back and forth can vary from a green, blue, orange, or yellow hue. This coloration often changes over the first three months of life. Some dogs, most commonly those with blue eyes, don’t have a tapetum. So, when you take a picture of these dogs, rather than getting the greenish-colored reflection from the tapetum, you instead often get red eyes – coming from the red blood vessels at the back of the dog’s eyes.
Importance of Understanding Dog Vision
Information about what and how dogs see can help us understand how vision works and is affected by the environment for dogs and for humans. It also helps us breed and train working dogs for specific tasks that are dependent on different types of vision.
For example, a Labrador Retriever must visually track and mark the places where birds fall in the field or the water. Border Collies must detect the smallest movements of their sheep. And guide dogs need excellent peripheral vision to keep their human partners safe.
If you’d like a more visual sense of a dog’s night vision, you can experience the spectrum of vision dogs possess online. This image-processing tool allows users to upload a photo that can be modified to show the difference between how humans and dogs see it.