How Does a Dog See the World?

Dog eye
Photo: Monica Martinez Do-Allo/Shutterstock

Not much gets past a dog's nose, but what about those soulful eyes? What do dogs see when they gaze up at us or ogle a squirrel?

Despite an old misconception, dogs can see in color. Yet while human eyes contain three kinds of color-sensing "cone" cells, dogs have just two, leaving them red-green colorblind. Dogs also have less visual acuity than we do, which makes everything look blurrier, although they excel at motion detection and night vision.

We may never know what it's like to be a dog, especially without their sense of smell, but science can at least estimate what it looks like. The search engine Wolfram Alpha has a research-based dog vision tool, for instance, that edits photos to mimic canine eyesight. Here are a few examples, used with permission, to reveal the world as our best friends see it.

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Flowers

Photo: Wikimedia Commons/ Wolfram Alpha

To be fair, dogs know more about flowers than this. We often assume other animals share our emphasis on sight, but images can only scratch the surface of a dog's scent-centric existence.

Still, we know dogs lack the ocular equipment to see red, and a 2017 behavioral study backs that up. Using a modified version of the Ishihara color vision test, researchers found that dogs perform similarly to humans who are red-green colorblind. Dog vision is blurrier, though, since they have four to eight times less visual acuity. That's roughly 20/75 vision, meaning dogs lose sight of patterns from 20 feet away that most humans could see from 75 feet.

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Other dogs

Photo: 123RF/Wolfram Alpha

Since dogs can't see red, scientists used to think they use luster more than color as a visual cue. But a 2013 study disputed that idea, finding color is "more informative than brightness" for a dog comparing two objects that differ in both.

Fur color might therefore help dogs recognize each other from a distance, along with related signals like body size and shape. This chow's reddish coat may seem green to other dogs, but that skewed hue could still help them distinguish the chow from a Swedish Lapphund down the street — at least until they get close enough for a proper sniff-down.

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Humans

Photo: U.S. Library of Congress/Wolfram Alpha

Canine communication is big on folded ears, tucked tails and other body language, but pet dogs are also careful students of the human face. Not only can a dog identify her owner's face in a crowd, but research has shown she can even tell when a stranger is smiling.

Since former U.S. President Barack Obama is widely recognizable, our view of this modified image may resemble how dogs see a familiar human face. It's much blurrier than what we see, but that basic amount of visual information still sparks welcome-home frenzies from dogs around the world every day.

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Squirrels

Photo: Wikimedia Commons/Wolfram Alpha

Despite their limitations with visual acuity and color, dogs are uncanny motion detectors. A stationary squirrel might blend into the background, but any sudden moves could alert dogs as far as half a mile away.

Canine retinas are packed with light-sensitive "rod" cells, helping them detect even slight motion in daylight or darkness. A 1936 study on police dogs found that some could identify moving objects from 2,900 feet away, but their visual range dropped to 1,900 feet when the same objects were motionless.

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Bacon

Photo: 123RF/Wolfram Alpha

Bacon may smell great to a human nose, but imagine how it must smell to dogs. They have about 50 times more olfactory receptors than we do, helping make their sense of smell up to 100,000 times stronger. They can also hear it sizzling from four times farther away.

We might end up enjoying it more, though: Not only does bacon probably look greener and blurrier through dogs' eyes, but they have one-sixth our number of taste buds.