Ah, to know what goes on inside those puppy dog eyes. Aside from “food!” “ball!” “squirrel!” and “outside!”, people like to think their pets are contemplating life, maybe making minor judgments about us.
Whether they’re watching TV or surveying the scenery while on a walk, it’s hard to put ourselves inside their
shoes paws and really see what they see. But up until recently, humans thought they knew this one thing about canine vision: that dogs see life in black and white.
Wrong. Turns out they don’t even see in shades of gray. The misconception that pups are colorblind is actually a major dog myth. Alexandra Horowitz, the author of the 2016 book Being a Dog, recently explained to Business Insider that even though it’s difficult to know exactly which colors our pups see, the cones and rods which work as light receptors inside their eyes (as well as our own) are likely able to detect some colors. While humans can best see three colors of the spectrum — red, green and blue — experts believe dogs, who have less cones than us, may have the most sensitivity to two colors — yellow and blue. Horowitz says this vision field probably compares to what humans see at dusk.
However, dogs have more rods in their eyes than humans do, plus another layer of eye tissue, which means their night vision is better than ours. And while cats are the domestic pets most often lauded for being able to see in the dark, our friends over at Dogtime report that dogs’ vision at night is actually pretty comparable to that of their feline counterparts —and as much as five times better than that of humans. Dogs have larger pupils than us, allowing for more light to pass through, and (as mentioned above) more rods, which makes the image on the retina larger, even in dimmer light.
Dogs also have another, surprising advantage over people when it comes to detecting motion. Humans have something called a fovea in both eyes. It’s a small indentation in the retina that makes it possible for us to see sharp, vivid details. Because dogs don’t have foveas, they can’t see precise detail as well as us, but this lacking feature of the canine eye allows for far better motion and movement perception. Along with their sense of smell, it’s another reason why many dogs are such great hunters.
Finally, in terms of visual acuity, dogs are generally thought to have 20/75 vision, as compared to humans’ typical best 20/20 vision. This means our pups see in a somewhat softer, blurrier focus from far away than we do. But it also explains why they love on us and lick us no matter what we look like! Perhaps unconditional love and fuzzy eyesight go hand in paw, after all.