My Pogs loves to play fetch.
But sometimes she struggles to find certain balls in the grass. She sniffs around, getting quite close but without seeing what’s in plain sight.
All of which set me wondering: Why does she have such difficulty locating certain balls by sight?
Don’t get me wrong — she hasn’t got a problem with her eyesight. But she does have normal “doggo-vision”? The latter makes it more difficult to spot some objects based on their color because dogs don’t see color as we do.
So what exactly do dogs see?
Do Dogs See in Color?
So what’s “normal” — what we see or what a dog sees?
Either way, one thing’s for sure: When people and pooches look at a rainbow, they see a different color spectrum.
Yes, dogs do see in color — but their color spectrum is more muted and muddy than what we see.
Instead a rainbow made up of red, orange, yellow, green, blue, indigo and violet, they see a study in shades of khaki, ranging from brown through yellow and mustard to blue.
This difference is because the canine retina contains only 2 types of cone (humans have 3) and in fewer numbers.
The retina (light-sensitive layer at the back of the eye) is made up of rods (designed for night vision) and cones.
Given that the retina is a finite size, you can only have a finite amount of rods and cones.
Human evolution favored cones, so in daylight, we see in glorious technicolor, but we fumble around in the dark.
Dogs, however, went down the other path: Their sight favors rods over cones. As a result, dogs see better in the dark than people, although not quite as well as cats. But color vision is about more than the numbers of cones — it’s about how many types of cones.
For example, people have 3 types of cone, whereas dogs have just 2. So if vision were like the sense of taste, where people experience sweet, sour and bitter, a dog only tastes sweet and bitter, and misses out completely on the experience we know as sour.
In other words, dogs miss out on part of the color spectrum that we can see.
In practical terms, lacking one type of cone is like having a paint palate that’s missing some colors. Because of this, dogs have a different view of the world:
- Red: A dog sees a dirty brown color.
- Orange: A dog sees a shade of mustard.
- Yellow: This one’s similar; yellow is yellow, albeit with a green tinge.
- Green: Nope, this isn’t green but instead a dirty mustard shade again.
- Blue: Bingo! Blue is … blue.
- Indigo: Oops, indigo is also blue. Confusing, no?
To a dog, a red ball on green grass looks like a brown thing against a shade of dirty mustard.
No wonder that a game of fetch can become a trial if the dog didn’t see where the ball landed.
This backs up what I’ve noticed with Pogs. She’s much better at finding a traditional yellow tennis ball than that bright red one that — to me — stands out clearly against green grass.
To her, that red ball is a brown object on a brown background.
How Dogs See in the Dark
So dogs sacrificed cones for the sake of rods. Does this mean dogs have the equivalent of night vision goggles?
Not quite, but they do have several adaptations that give them the edge on a dark night.
A Large Pupil
In the old days of 35mm cameras, you opened the aperture to let more light reach the film at the back of the camera. The canine eye has a similar system.
Their pupil (the black circle inside the dog’s colored iris) can dilate hugely. Much like a black hole, this sucks light into the eye, harvesting every scrap of available light.
A Reflective Tapetum
Traveling at night, your car headlights pick out cats eyes’ because they reflect light back at you.
A similar thing happens at the back of the canine retina. Dogs have a super-reflective layer that bounces light around to magnify it.
Lots of Rods
When the light hits the retina, those super-sensitive rods register it to piece together an image. Add all this together, and it makes for improved eyesight in dim light.
A dog sees 5 times better than people in the dark, but a cat sees 6 times better than a dog in the dark.
Here’s a handy visual aid of how dogs see the world:
Eyesight Is Less Important to Dogs Than It Is to People
When all’s said and done, dogs are less dependent on sight than people are.
This is because their other senses are so highly developed.
Indeed, a dog’s sense of smell is vastly superior to ours. Their ability to pick up scents could be described as a superpower, with the average dog being able to detect 1 bruised apple amid 1,000 perfect ones.
Add in those amazing whiskers and the sense of touch, plus an awesome ability to hear, and it pushes the importance of sight into the background. All of which is reassuring should a dog go blind for any reason, because they often cope just fine.
Quite simply, I must be patient when Pogs loses her red ball in the grass, because it’s not as obvious to her as it is to me.
Also, if yours is an older dog with failing eyesight, don’t worry — they’ll do just fine.
- Miller, Paul E., DVM, and Christopher J. Murphy, DVM, PhD. “Vision in Dogs.” Journal of the American Veterinary Medical Association 207, no. 12 (Dec. 15, 1995): 1623–1634. http://www.rctn.org/bruno/animal-eyes/dog-vision-miller-murphy.pdf.
- Granar, M.I., B.R. Nilsson, and H.L. Hamberg-Nyström. “Normal Color Variations of the Canine Ocular Fundus: A Retrospective Study in Swedish Dogs.” Acta Veterinaria Scandinavica 53, no. 1 (2011): 13. doi: 10.1186/1751-0147-53-13.
This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Nov. 29, 2018.
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