Veterinary ophthalmologist Stephanie Pumphrey, V08, an assistant professor at Cummings School of Veterinary Medicine, responds
Photo: Bruno Rodrigues B Silva / Shutterstock
Dogs do see color, although not as vividly as people do.
The retina is the thin layer of tissue at the back of the eye that transforms light into a signal that can be transmitted to the brain. That signal to the brain is what we perceive as vision. Cone photoreceptors are the cells that the retina uses to sense color.
People have three kinds of cone photoreceptors. One type senses red wavelengths of light, a second senses yellow-green light, and the third senses blue light. Our eyes and our brains use the information from these three different types of cone photoreceptors to perceive a rainbow of colors.
Dogs, cats, horses, and many other mammals only have two types of cone photoreceptors, however. They lack the cone photoreceptor that senses red light. Because of this, while they do perceive color, their view of the world is muted compared to ours—kind of like looking at an old-fashioned black-and-white photo that has been hand-tinted.
On the other hand, birds and other non-mammalian species sometimes possess not only three but four or more types of cone photoreceptors—allowing them to see colors in the infrared or ultraviolet portions of the light spectrum that are invisible to people. This ability may help them find food or recognize a particularly attractive potential mate.
