You don’t see many dogs wearing glasses, so their eyesight must be better than humans, right?
Okay, that may not be the best place to start for a discussion on whether or not dogs can see in the dark, but here we are anyway. The truth is, dogs can’t see in complete darkness, but they do have better night vision than their human counterparts.
Why is that?
The Anatomical Structure of Your Dog’s Eyes
Your Dog’s Retina
To understand why dogs can see better in dim light, you need to understand the structure of the eye, particularly that of the light-sensitive retina. Located in the back of the inside of the eyeball, the retina is made up of two types of light-sensitive cells called rods and cones, and each serves a certain purpose.
The number of cones in human or animal eyes determines how well they can see detail as well as color. Humans also have a cone-rich structure called a fovea in the back of the eye that further enhances this ability. Several bird species, such as hawks, actually have two foveas, which goes far in explaining why they can detect a tiny mouse in a field while soaring a hundred feet above it. Dogs have far fewer cones than humans, and as a result, they have less visual acuity. Their ability to see detail is six times poorer than that of humans.
On the other hand, the canine eye has far more rods than that of humans. These light-sensitive cells help dogs see in dim light and better detect motion. Because of these extra rods, dogs can see in light that is five times dimmer than that which humans can navigate.
The pupils in dog’s eyes are also larger than that of humans, another factor that helps them see better in the dark.
The Mirror Within Your Dog’s Eye
Another reason dogs can see in the dark better than humans is because of the reflective layer under their retinas called the tapetum lucidum. Canines, including dogs, wolves, and coyotes have this feature as well as cats, deer, and several other species. This special layer reflects light back through the retina allowing animals to see better in low light. When you see your dog’s eyes glow when illuminated by a bright light, you’re actually seeing the tapetum lucidum.
Are There Other Factors That Impact a Dog’s Ability to See at Night?
Because of the lower number of cones in their retina, dogs have developed other means to help them see better at night.
As mentioned earlier, the light-sensitive rods in dog eyes not only help them see better at night but also detect motion more rapidly than human eyes. Because of the fewer cones in dog’s eyes, they can only see blue-violet, yellow, and gray colors. This is referred to as red-green color blindness. (And it’s why so many dog toys come in blue and yellow colors). Dogs’ enhanced ability to see movement helps to offset their diminished ability to see colors as well as the lost visual detail due to the fewer cones in their eyes.
Field of Vision
Depending on the breed, the position of a dog’s eyes garners them a greater peripheral vision that than of humans–anything from 240 to 270 degrees. In comparison, a human’s peripheral vision is about 180 to 190 degrees.
Unfortunately, an increased peripheral vision often goes hand in hand with poorer depth perception. In order for humans or animals to perceive depth, they need to have binocular vision, an overlap in the field of view for each eye. Additionally, the length of a dog’s nose can also interfere with binocular vision.
Because of some of the shortcomings in dogs’ visual abilities, they tend to rely more heavily on other senses, such as their strong sense of smell as well as their sense of hearing.
Can dogs see in total darkness?
Can dogs see in the dark? Yes, they can, but they can’t see in total darkness. As different as dog’s eyes are from humans, we both share the necessity of having to have at least some light in order to navigate in dim light.
Do dogs need a light on at night?
If you’ve ever lost electricity in the evening after dark, you know how it feels to stumble around trying to find a flashlight or a candle and matches. You may even have cursed yourself for not having set one out in a predetermined spot. Just like you, your dog may be able to find his way around if he is well-acclimated to the set-up of your home, but he probably won’t like it.
Despite having eyes that perform better in low light, if left to deal with darkness for an extended period of time, your dog is apt to display anxiety. He may whine or bark in their crate at night or become destructive. He might also become frightened by unfamiliar noises, which is why so many pet owners struggle to keep dogs calm during fireworks. Using a simple plug-in night light, particularly one that has a sensor to make it come on only when it detects the loss of light will not only help your dog feel comfortable, it will be helpful for those humans in the household that shares the same space.
Do dogs have night vision?
They certainly have better vision at night. The larger pupil, the makeup of their retina, and the reflective layer all help to enhance their night vision.
Should dogs sleep in the dark?
Your canine companion should be able to sleep without issue in the dark. Some dogs, however, may become less comfortable or even fearful in complete darkness, which may also set off unnecessary barking. In that case, a simple night light may solve the problem by providing a modicum of comfort in a completely dark environment.
Just like humans, your dog’s vision can become diminished or impaired due to age, illness, or accidents. Most of the time, veterinarians will suggest not making any great changes to the layout in your home so your pet can more easily maneuver the landscape. She may also suggest you limit his exercise to walking him on a leash. However, believe it or not, veterinary ophthalmologists can also test your dog’s sight and have him fitted for “doggy glasses” to address problems with diminished vision, light sensitivity, or as a means of protection from airborne debris when he hangs his head out your car window.
After all, a happy dog should be able to enjoy the best vision he can under any conditions!