Do Dogs See Color?
Color blindness in dogs is a myth. The basis for this myth is not known, but it persists in culture. The truth is dogs do see color. While dogs can't appreciate all the colors that humans see, their world is not entirely black and white. In fact, dogs live in a pretty colorful world.
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 identify combinations of red, blue, and green. Dogs possess only two types of cones and can only discern blue and yellow (dogs have dichromatic vision).
Although humans have more cones, allowing us to see more colors and see them brighter than dogs see them, dogs have more rods. Having more rods gives dogs an advantage when it comes to seeing in low light and for identification of moving objects.
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 humans: red-green color blindness and blue-yellow color blindness. A person with red-green color blindness can't distinguish between these two colors. Likewise, a person with blue-yellow color blindness can't tell the difference between yellow and blue.
Veterinary ophthalmologists have determined that a dog's normal vision is most like a person who has red-green color blindness. Dogs' eyes have receptors for blue and green shades, but not for red shades. As a result, it appears that dogs cannot easily distinguish between yellow, green, and red, but they can identify different shades of blue, purple, and gray. No further degrees of color blindness have been recorded in dogs.
Therefore, dogs don't appreciate the entire spectrum of color that humans do, but they do perceive color. They just don't see the "true" color of an object. For example, the color red appears dark brownish-gray or black to a dog. Further, the colors yellow, green, and orange all appear yellowish to a dog. However, our furry friends see blue really well. Purple appears the same as blue to them. So, when playing a game of fetch, dogs can't distinguish between a red ball and a yellow ball. Fortunately, they have a great sense of smell, so they can usually identify their ball.
In addition to color perception, there are other visual differences between canines and humans. Dogs are more near-sighted than humans. Further, dogs are less sensitive to changes in brightness. However, canines do have some visual advantages over humans. Since their eyes are set more on toward the sides of their heads, it allows them to have a broader range of peripheral vision than possessed by humans. The tradeoff is a smaller range of visual acuity so dogs don't have the depth perception we humans possess. Additionally, as mentioned earlier, dogs possess more rod cells in the retina than their human friends. Rods are responsible for detecting motion, even small movements at great distance. Therefore, when compared with humans, dogs see better in dim light (dawn and dusk) and can more accurately detect motion.
Knowing how and what your canine friend can see will help you make good choices for him or her. For example, keep your dog's color range in mind when shopping for toys. Your dog will enjoy blue and yellow toys more than red ones. You will know that to get his or her attention, you should stand directly in front of her or him, where his or her visual acuity is greatest. Additionally, you will better understand why your dog gets distracted during a game of fetch as she or he hones in on a bird flying 40 yards away.
Next time you are enjoying a bright blue sky or a colorful rainbow in the sky, your furry friend can enjoy it, too. He or she can see that blue sky and, although he or she won't see all the colors of the rainbow, he or she will see pretty yellow and blue. Dogs are happy with their colors of the world.
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