By Monica Weymouth
In some ways, humans and dogs see the world very differently. What you perceive as a fire hydrant, your dog sees as a can’t-miss communication center. It may look like an ordinary vacuum cleaner to you, but your pooch obviously detects something more sinister lurking in the closet.
One thing we do have in common with our four-legged friends? We see the world in color.
Are Dogs Color Blind?
Although early research suggested that dogs were unable to perceive color, the popular notion that dogs see in black and white turns out to be nothing more than an oft-repeated myth.
“Contrary to popular belief, dogs can see color, too,” says Dr. Shelby Reinstein, a veterinary ophthalmologist at Veterinary Specialty and Emergency Center in Pennsylvania. “Color vision is possible due to specialized types of photoreceptor cells in the retina called cones. When these cells are stimulated, they transmit a signal to the brain, which is perceived as a particular color. Humans possess three types of cones. On the other hand, dogs possess two types of cones, so their ability to perceive colors is limited compared to humans.”
Humans have blue, red, and green cones, whereas dogs have a blue cone and a visual pigment that falls between a human red and green, describes Dr. Gustave Aguire, professor of medical genetics and ophthalmology at PennVet. “The eye really is complex, and the retina is an extremely beautifully organized structure meant for capturing light,” he says.
In comparison to rods, cones also excel when it comes to the ability to see fine detail. Therefore, people are better able to make out the minutia of things seen up close in comparison to dogs.
Can Dogs See Color?
So what exactly is your pup seeing at the dog park? Even without being able to interpret every hue, his afternoon isn’t all that different from yours—especially if you experience a form of color blindness. “Dog color vision is quite similar to a person who has red-green color blindness,” explains Reinstein. “Dogs see shades of blue, yellow and green, which when combined, can be perceived as grayish brown, dark yellow, light yellow, grayish yellow, light blue and dark blue. This probably explains why dogs love chasing a bright yellow tennis ball on the green grass under the blue sky.”
Sight, of course, is much more complex than color—it’s not just about the colors of the rainbow, but the arc of the rainbow, the sharpness, the plane flying through it. While the human eye has advantages when it comes to perceiving some colors and fine detail, in other environments, canines have the upper hand. “While we do not think that dogs can focus as clearly on close objects, and therefore rely on smell and taste, we know that they are able to see better in dim light,” says Beale. “They possess more rod photoreceptors for dim lighting in the middle of their retinas and have a tapetum lucidum that reflects light through the retina twice—we see this as dogs' eyes shining in the dark.” Rods are also better at picking up movement than are cones. So, if your dog appears to be tracking something at a distance, particularly in dim light, you should pay attention.
“Even though a dog’s vision palette isn’t as vibrant as ours, their other senses are so heightened,” adds petMD trainer Victoria Schade. Take, for instance, a dog’s keen sense of smell. Dr. Katy Nelson, veterinary expert for petMD, shares an example of smelling a bowl of salad. “We would smell the salad and maybe the salad dressing,” she says. “If a dog smells that same salad, he’s going to walk up and smell the tomatoes, and the cucumbers, and the specific type of lettuce, and anything else you put in there. He’s going to smell all of those individual smells.”
While researchers believe that all breeds perceive roughly the same spectrum of colors, other components of sight do vary depending on anatomy and size, which can differ wildly when it comes to dogs. “Certainly the perspective differs between a Great Dane and a Chihuahua,” says Dr. Brady Beale, a clinical instructor of ophthalmology at the University of Pennsylvania’s PennVet. “Additionally, the position of the eyes on the head of the dog varies between breeds. If eyes are close together and a nose is relatively short, there will be a bigger overlap in the visual fields of the two eyes. This is called binocular vision, and larger overlap would provide more information for depth perception.”
So if you’ve been wondering whether dogs can see colors or if dogs can see in relative darkness, the answer is simple—yes. While their vision capabilities are slightly different than humans and they can see better in low light settings, dogs generally experience the world of sight in a similar way to their two-legged counterparts.
Even if their ability to perceive color is limited, “I certainly don’t think that changes their perception of the world by any means,” Nelson says. “I do feel like they get the full experience of it out there.”
Image: Annette Shaff via Shutterstock