The question ‘do dogs see in color’ has been making the rounds ever since that famous scene in Cats vs. Dogs. In this scene one of the dogs must disarm a bomb with different colored wires, the issue being that in the dog’s vision the wires are just varying degrees of grey. However, this is not technically true.
The myth that dogs cannot see in color was spread because of the word colorblind. Just like in humans color-blindness is not being blind to all color, but rather being blind to specific colors in the visible light spectrum. Dogs do not see everything in varying stages of grey. Scientists figured this out almost 30 years ago, but only with the rise of the internet is it becoming more common knowledge
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How do eyes see color?
Eyes ‘see’ color using very specialized cells, known as cones. These are cells that are able to catch the light and convert it into data that is then fed to the brain. Unlike rods, the other light-catching cells in the human eye, cones contain three different photopigments. Photopigments are chemicals that will change their state depending on the wavelengths of light entering them.
Now in cones, these three photopigments are attributed to the three primary colors we see; blue, yellow and red. These are different colors because the length of the wave that makes up their light is different as illustrated below:
What you can see here is that the range between each of the waves is different, with red being the longest, and blue being the shortest. This is very important as if all the waves were the same length we would see everything in one color making depth perception and seeing anything in 3 dimensions impossible.
So these three different cones allow us to see three primary colors. Now the actual number of these cells in your eyes is close to 7 million. This value represents how rich or intense the colors we see will be. Think of your favorite colored t-shirt the day you bought it and then three years later after it has been washed 1000 times. After all these washes the color begins to leave the shirt, and it looks faded. In the same way, if you had fewer cones, colors would look more faded.
Neitz’s Discovery
In 1989 Jay Neitz, a member of the Department of Psychology at the University of California, published paper titles ‘Color vision in the dog‘. In this paper, he described a test. Three domestic dogs were shown three light panels in a row. Now two of these panels were the same color, but the third was different. They were shown these in a random order. The dogs were trained to press the panel that was different, which would then give them a treat.
This test was completed a vast number of times. It was also done with a large number of different colors that humans would be able to differentiate between. Neitz saw two things. First was that if you feed a dog a large number of treats they start to get quite fat. And second, Neitz saw that when the test was done with colors in the Yellow to Blue spectrum of light, the dogs had a high rate of success. But in the Red to the Yellow range of light the dogs had only a small amount of success, that could be put down to random occurrences.
Why does this happen?
Dogs have two types of photopigments in their cones, in comparison to humans three. This means that where we will see a mixture of blue, yellow and red dogs will only see yellow and blue. So if you show a dog something like a red chew toy, they will actually see it as dark brown color. Therefore if you are out shopping for a chew toy for your dog, and can’t decide between a red and an orange toy, remember that it makes very little difference to them.
Another aspect of dogs vision is the actual total number of cones that are present in their eyes. Our central retina, the center of the human eye where the cones are located, is made of 100% cones. Due to the way that dogs eyes work, and the way they have evolved to fit their lifestyle, their central retina is made up of only 20% cones. So the dog’s vision will be much closer to your 3-year-old t-shirt, with ours being like the new one. When you are throwing your bright red toy for your dog, and they seem to ignore it, they are actually looking for an entirely faded brown chew toy.
Why do dogs eyes work in this way
So why is it that dogs eyes have evolved in this way, surely seeing in color is a beneficial trait in all mammals? Before they were domesticated and became, mans best friend dogs were predators, similar to wolves. They mostly hunted late at night. Therefore dogs eyes evolved over thousands of years to be able to see well in the dark.
Rods are the other light-catching cells in human eyes. They don’t see color like cones do. Instead of â catching’ light and measuring the wavelength like cones, rods measure the intensity of light, i.e., how bright it is. They are far more sensitive to light than cones. This makes them fantastic for seeing in low light situations.
What you will find in dogs, and all animals that operate at night is that the ratio of rods to cones is much higher. Giving them the ability to see well at night, but seeing less color because of it. The rate in humans is around 20 rods to every 1 cone. In dogs, it is about 200 rods to every 1 cone.
This more significant number of rods also gives dogs a more substantial advantage in motion detection. It is another beneficial trait in a predator. They can even see the flicker on your TV screen as the next frame loads. Even more interesting the fact that dogs may not actually recognize humans through sight by the way they look, but more by the way they move.
So there you have it. Dogs can see in color! You can now use this knowledge when playing hide and seek with your puppy and never lose again, just remember not to move, at all. Or possibly to buy it a chew toy that it can actually see.
Bonus fact
The animal with the most significant number of different cones is the Mantis shrimp. It has 16 compared to the humans 3. This means that it can see 16 primary colors!
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