The eyes of dogs are uniquely designed to give them maximum sight to see the slightest movement at long distances, but they still don’t have 20/20 vision. When I watch one of my dogs gazing into the distance or seemingly searching the sky, I can’t help but wonder what they see that I don’t. The world from canine eyes is much different from ours, and yet, dogs can still see the world far better than we can. And despite popular belief, dogs can see colors. Just not in the same way we see them.
Without his nose, a dog would be at a disadvantage when it comes to moving through his world. Depending on the breed, dogs have 125 to 300 million scent receptors compared to our 5 million. It’s the smell that attracts your pet to his favorite CANIDAE treats or dog food, not the shape or color. If we saw our food like dogs see theirs, most food wouldn’t be very appetizing to us by sight alone.
Like cats, canines see best in the low light of dust and dawn. Their eyes are designed to pick up the slightest movements, and they have much better peripheral vision than we do. However, a dog’s vision is half as sharp as ours. Color, focus and detail are sacrificed in order for dogs to see subtle movement.
The retina of the human and canine eye is made up of two types of photo receptors: cones and rods. Cones give us color perception and details; we have three types of cones and dogs have two. Rods detect motion and make night vision possible; dogs have far more rod cells than humans. With the higher concentration of rods, dogs have no trouble picking up movement even at night. Seeing things in focus isn’t necessary to track prey as long as there’s movement. Their excellent sense of smell and hearing also help when there’s no motion to detect.
Dogs can see certain colors, but they are colorblind much like a colorblind human. Both have similar eye structures that are missing the extra cone most of us have. We are trichromatic, which means we see the primary colors of blue, yellow and red. Dogs are dichromatic and can only see two primary colors – blue and yellow.
The wide variety of colorful toys in pet stores isn’t for the benefit of dogs, it’s to entice us! If colors were based on what a dog can actually see, we would be buying toys in only shades of blue and yellow. A red or orange ball appears in the yellow spectrum for dogs, and if you roll that red ball in green grass, dogs see both as a shade of yellow. So your dog tracks the ball by its movement, not the color. Humans see all of the colors in the rainbow unless they have colorblindness. Blue, green, violet, orange, yellow and red to our dogs are shades of blue, shades of yellow, shades of gray or a grayish brown.
At one time researchers thought dogs might use the brightness of a color to distinguish between objects, but one study indicates dogs rely on color alone. For example, if you wanted to teach your dog to bring you a toy in one of the shades of color dogs can see versus another color, he has the ability to learn the name of the toy and the color.
Why some dogs scare easily is because their vision is blurry. They have 20/75 vision, which means they can see patterns up to 20 feet away that most people can see at 75 feet. Canines know the shape of prey, deer, other dogs and animals, and people. If the human shape is changed, like holding an umbrella or wearing a hat or a shape-altering Halloween costume, a dog that isn’t well socialized may be startled or confused.
A dog’s eyes may not be as focused or clear as ours, or see all of the colors of the rainbow, but when you add in their sense of smell and hearing, dogs “see” their world much better than humans.
Top photo by Putneypics
Middle photo by Rob Unreall
Bottom photo by John Talbot
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