Have you ever thought about how dogs see the world? I’ve often wondered why Haley doesn’t seem to notice our resident chipmunk sitting on the edge of the porch during the day, even when I try to point him out to her. Yet, she’ll let me know that she sees something up ahead while we’re walking through our wooded neighborhood late at night. It always scares me a little bit when she alerts me to something lurking in the dark and I’m unable to see right away that it’s only a meandering cat or deer. Yes, our dogs definitely see the world differently than we do.
People used to think dogs were color-blind, but research has shown that dogs do see some colors, just not as many as we humans see. Here’s a quick refresher from science class to help explain why.
It’s All About the Rods and Cones
Humans and dogs both have photoreceptor cells called rods and cones in the retina of their eyes. Rods are more sensitive to changes in light and in detecting shapes and movement, but rods are not sensitive to color. Rods help us see when it’s dark but we’re basically color-blind in low-light conditions. Cones are better at detecting color and creating fine detail; it’s what we rely on in daylight to view all those amazing shades of color. Hang in there with me, all this scientific talk gets more interesting when you compare the rods and cones of the human eye to that of a dog’s eye.
We humans have three types of cones that are sensitive to the colors red, blue and green whereas dogs have only two types and they mostly see the colors yellow, blue and various shades of gray. The image below helps illustrate the comparison mapping of the color ranges.
Humans have 6 million cone cells compared to the 1.2 million that dogs have. We can see about a million different shades of color and all those colors help distinguish fine details in our surroundings. Dogs can only see about 10,000 different shades of color and far less detail because of their low number of cones. When it comes to comparing the number of rods, it’s a different story. Although it’s not known how many rods dogs have compared to our 120 million, we do know that a dog’s eye is about five times more sensitive to light, so perhaps they have five times more rods than we humans have.
What Colors Can My Dog See?
Researchers are pretty sure this is how dogs see color: Dogs don’t see shades of red or green. Reds appear to be dark gray to black. Orange, yellow and green appear to be different shades of yellow. Blue and violet colors appear as different shades of blue to blue-gray. Click on the picture below to view how your dog would likely see the image. Notice the difference in colors as well as the lack of detail dogs have. The green, red and orange toys tend to blend in with the grass but the blue toys are much easier to see.
Click the image below.
Practical things to consider about how your dog sees color.
I’ve never tried agility with Haley and have never owned hunting dogs, so I’m hoping some of you experts will weigh in with your opinions on those last two points.
Your Dog’s Vision Acuity
Another difference in how dogs see the world is they don’t have sharp distance vision. They are nearsighted to varying degrees but on average their vision is about 20/75 which is much worse than a typical human’s vision acuity. This could explain why your dog might not seem to recognize you or other family members at a distance. You appear as an outline of a figure until your dog approaches closer or perhaps he picks up your scent or recognizes your unique body movements. This is something to keep in mind when working on recall at a distance; some trainers even suggest using arm movements along with the recall command.
Check out the two images below to compare how your vision acuity likely compares to that of your dog’s vision acuity.
The Good News
If you’re starting to feel sorry for your dog, don’t worry. In some ways, your dog’s vision outperforms your own. Remember those rods? They play a big role in how dogs are able to see and hunt prey at night. Here are three amazing qualities about a dog’s eye.
Humans don’t necessarily see better than dogs, we just see differently. Even though we see more colors, details and have better distance vision, a dog’s sense of sight was designed to be efficient for hunting, especially at night.
If you feel bad that your dog doesn’t see as well as you, remember that dogs primarily “see” the world through their sense of smell. I’m sure our dogs would feel sorry for us if they knew how much we’re missing by not having the ability to experience so many varied aromas.
Have you noticed anything unique about your dog’s vision or how he sees the world?