It’s long been debated and contested whether or not dogs can see what they can. There is a peculiar feature of dogs featured in many movies namely that dogs are colorblind. For this reason, many people believe that they see only black and white. However, is this actually true?
Dogs Can See Colors
Yes, they can. Like us, dog eyes have a cornea, pupil, lens, retina, and rods and cones. However, there is a difference between what we see and what dogs see.
A human eye’s retina consists of certain receptors called ‘cones’ and ‘rods’. Cones are responsible for perceiving colors. A human eye consists of 3 types of cones, which are activated by a certain wavelength of light that falls upon it. Normally, a human eye has the type of cones that can detect the three basic colors: red, green and blue.
However, in the case of dogs, there are only 2 types of cones, which can perceive only 2 colors: blue and yellow. This definitely allows them to see fewer colors than humans, but that certainly doesn’t make them completely color blind.
So what is called colorblind in dogs?
Dogs do not see in black and white, the word “color-blind” here means they have only two color receptors (called cones) in their eyes, whereas most humans have three as we mentioned above.
The color receptors in the eye work by perceiving only certain wavelengths of light. In humans, each cone perceives, roughly, the wavelengths of light that correspond to red, green, and blue-violet. By overlapping and mixing the spectrum of colors that the three human cones perceive, we are capable of seeing a wide variety of colors. In dogs, however, the two-color receptors in the eyes perceive wavelengths of light that correspond to blue and yellow, meaning that dogs see only in combinations of blue and yellow. So instead of bright red roses, dogs likely see yellowish-brown petals, and lively green grass looks more dehydrated and dead.
Is a dog’s vision based on movement?
A dog’s retina doesn’t have the ability to sharpen details the way human retinas do. For this reason, dogs rely much more on movement (and smell, obviously) to determine what’s happening. Dogs rely mainly on movement and contrast to identify objects. A large number of rods help dogs detect light and dark and help them perceive light and movement even when it is dim out.
So, when your dog is chasing a ball through the grass or fetching a stick, it’s quite possible she’s relying more on the clarity of movement than searching for the actual color of the item against the color of the grass.
What colors dogs actually see?
Research by the clinical ophthalmologist Dr. Jay Neitz at the University of California, Santa Barbara in 1989 reported that humans see the rainbow as violet, blue, blue-green, green, yellow, orange and red. The long-held belief has been that our canine companions see it as dark blue, light blue, gray, light yellow, darker yellow (almost brown), and very dark gray. In short, dogs see the colors of the world as basically yellow, blue and gray.
Not all scientists agreed with Neitz, so a team of scientists from the Laboratory of Sensory Processing, Institute for Information Transmission Problems, Russian Academy of Sciences designed a clever experiment to settle the debate of color versus brightness.
They trained dogs to receive a food reward when shown four different colored pieces of paper, dark and light yellow, dark and light blue. They then introduced dark and light shades of other colors the dogs hadn’t been taught. A significant majority of the dogs chose the dark and light colors they’d been shown, not the dark and light new colors. This proves dogs can use color to differentiate rather than brightness. Dogs can most certainly see in colors, at least blues and yellows as reported by Neitz.