When you look at a rainbow in the sky, you see shades of red, orange, yellow, green, blue, indigo, and violet. Can your canine friend distinguish the same range of color that you do? Does he see bands of black and white? Do the colors look blurred?
How dogs see color is a long-standing topic of research and the results are pretty amazing. While dogs cannot appreciate all the colors that humans do, their world is not entirely black and white. In fact, dogs live in a colorful world.
What colors can dogs see?
Color is discerned by the nerve cells in the eye. The retina of the eye has two main types of cells: rods, which detect light levels and motion; and cones, which differentiate colors. Human eyes have three types of cones that can identify combinations of red, blue, and green. Dogs possess only two types of cones and can only discern blue and yellow. This limited color perception is called dichromatic vision.
While humans have more cones, allowing us to see more colors and brighter colors than dogs, dogs have more rods, giving them the edge when it comes to seeing in low light or identifying moving objects.
What is color blindness? Are dogs color blind?
Color blindness is the term used for differences in the ability to perceive color. In humans, the degree of color blindness depends on which color receptors in the eye are affected. There are two basic types of color blindness in people: red-green color blindness and blue-yellow color blindness. A person with red-green color blindness cannot distinguish between these two colors. Likewise, a person with blue-yellow color blindness can’t tell the difference between a yellow shirt and a blue one.
"A dog’s normal vision is most like a person who has red-green color blindness."
When it comes to distinguishing color, a dog’s normal vision is most like a person who has red-green color blindness. No further degrees of color blindness have been recorded in dogs.
How does a dog’s vision compare to human vision?
Dogs can perceive different colors, even if they cannot appreciate the entire spectrum of color that humans do. They just may not see the “true” color of an object. They are also less sensitive to changes in brightness, so they can’t perceive color in the rich, vibrant tones that we do.
For example, red appears dark brownish-gray or black to a dog. And yellow, orange, and green all look a bit yellowish to a dog. Our furry friends see blue well, but purple looks the same as blue to them. When playing a game of fetch, dogs cannot tell the difference between a red ball and a yellow ball. Luckily, they have a great sense of smell, so they can usually identify their ball and avoid mix-ups when playing a game of fetch in the park.
In addition to color perception, canines and humans have other visual differences. In some respects, canine vision is not as acute as human vision. Dogs are more near-sighted than we are. When looking at an object from the same distance, the object may appear crisp to us, but blurred to our dogs.
Are there other visual differences between dogs and people?
Canines have some visual advantages over humans. Dogs have eyes that are set more on the sides of the head, which allows them a broader range of peripheral vision than we have. The trade-off is a smaller range of visual acuity, so dogs do not have the depth perception that we do.
Also, dogs have pupils that dilate maximally, allowing them to capture as much light as possible. They also have reflective cells under the retina, which form the tapetum. The tapetum reflects all the light information back through the retina, increasing a dog’s ability to see in low light. It is also what makes a dog’s eyes glow at night or when a photo is taken with a flash.
"When compared to humans, dogs see better in dim light (dusk and dawn)
and can more accurately detect motion."
Dogs also have more rod cells in the retina than their human friends. Rods are responsible for detecting motion, even small movements at great distances. So, when compared to humans, dogs see better in dim light (dusk and dawn) and can more accurately detect motion.
Why do dogs’ eyes work like this?
Dogs are equipped with visual accommodations that allow them to survive and thrive in the wild. Seeing well in dim light and picking up slight movements in the forest at great distances improve the dog’s hunting ability. These assets also help dogs know when they are the prey and need to flee.
Times have changed, and most dogs are members of our human families now, so we provide them with nutritious food and protect them from predators. Even so, these visual abilities remain in the canine family.
