In the middle of the night, you wake up to let Rover outside. Your eyes might be open, but your shoulder hits the corner of the wall, you trip over a dog toy, and you can barely navigate the path to the back door. Even as your eyes adjust to the dark, you still struggle to see.
But your dog sees just fine. He’s outside sniffing everything in the yard, roaming around, picking up sticks, even looking up into trees for a squirrel or bird, and he’s not walking into anything. While he roams around like its bright and sunny outside, you grab a midnight snack and wonder how on earth is he seeing things right now?
The Root of the Behavior
Dogs, similar to other animals, have better night vision than humans. Before dogs became domesticated, they hunted during low-light times, like dusk or dawn. Their ability to see images and shadows was necessary for survival and their eye structure is made to optimize this ability.
A dog’s eye has a similar composition to a human’s eye, but with a few significant differences. A dog’s pupils are larger so more light can get in. Have you ever seen your dog excited after chasing a squirrel and noticed his pupils are larger than usual? Or when he wakes up his pupils are smaller? This natural ability is to help his eyes gather as much information as possible. A human has this ability, too, and our pupils will dilate if something is exciting or enticing, or we are in low light.
A dog’s retina has cells that are sensitive to light and motion, called rods. This helps a dog differentiate between lights and shadows and gives them the ability to see more clearly at night. Humans have these too, but dogs have more, which gives them that midnight advantage.
Another feature of the dog’s eye is the tapetum lucidum. This feature lies just behind the retina and is a reflector. It mirrors light through the retina, which increases the amount of light a dog's eye captures. This is also the mechanism that makes a dog’s eyes glow in the dark and look creepy. However, the tapetum helps dogs see better than humans at night. Humans do not have this as part of their eye construction, which is one reason dogs see better at night than we do.
Dogs are also better at seeing at night because they have superior peripheral vision. Dogs have approximately 250 degrees of vision, while humans have approximately 180 degrees. Their eyes are also in the front of their head, rather than the side like a horse, so their range is better than other animals, too.
A dog's eyes receive more light than a human's, but less detail. If an object is 20 feet away, a dog will be able to see it as a human would at 75 feet away. He can make out the shape, but vague details. This is one area where humans have dogs beat.
Encouraging the Behavior
This is one feature of a dog that humans can’t control. A dog’s eyes are made to accommodate their predatory behavioral history and it’s a great tool for them. It could become problematic if your dog begins barking at night. Dogs bark for a lot of reasons at night. If your dog is a loyal watchdog and staring out the window, something in the distance might catch his eye and he’ll start barking. This could wake up you and your neighbors, but also start a call between other neighborhood dogs. The midnight howl could start, and your dog started it.
If this is the case, you’ll have to take measures to limit what your dog sees at night. Closing the blinds or limiting access to certain areas of the house would help keep the midnight guarding to a minimum.
One problem of aging we all face is parts of our body deteriorating. An aging dog’s vision could be compromised, which will affect his ability to see in the dark. Other problems include health conditions, like diabetes, cataracts, glaucoma, high blood pressure, or trauma to the eyes can cause a dog to lose his vision. If you notice your dog is walking into things like furniture, isn’t seeing squirrels in the yard like he used to, or you see any visible signs of problems in his eyes like cloudiness, take him to the vet.
Other Solutions and Considerations
Under the moon shadow, your dog can see much better than you. When you’re on night walks, he can guide you. If you ever go camping, he can be your fierce protector and see things as they approach. And if you want a dog for protection in your home, he’ll see intruders before you can rub your eyes to see clearly.
If your dog tends to bark at everything at night, take him to a trainer to learn how he can protect the house, but not cry wolf. You want your dog to be helpful, but you don’t want to wake the neighborhood up every time he sees an image 50 feet away.
Little Red Riding Hood said it best, “But Grandmother! What big eyes you have!” The wolf is a cousin of the dog and their eyes are very similar. Next time you see your dog’s pupils dilate or those creepy glow-in-the-dark eyes, know he is focusing in on something. It might be a squirrel, a cat, or even that midnight snack you just placed on the table.