It may surprise you to know that this well known statement is in fact a myth. Dogs in fact can see in color, even though the amount is minimal. Dogs can see the amount of color that a typical human with color blindness can. It is not so surprising that our vision is different from a dogs, but what is it that makes it different? Eyes seem to work the same way for everyone so why can humans see differently than dogs can? To answer this question we have to look at it from a biological stand point.
Color comes from the back of the eye from the retina. The retina contains calls called photoreceptors. The macula, which is the most sensitive part of the retina, holds millions of these photoreceptors. Cones and rods are the main two kinds of photoreceptors. There are more rods than cones. The rods are responsible for night vision and side vision. Rods are also more sensitive to light. Cones play a much larger role when it comes to our vision, and we rely on them a lot. The cones are responsible for responsible for sharp, detailed vision, and most importantly in my opinion, colored vision. Dogs also have cones and rods just like we do. Humans have 6,000,000 cones which help us perceive red, blue, green, and yellow. Dogs only have 1,200,000 cones and they can only identify blue and yellow.
How was this tested? Russian scientists from the Laboratory of Sensory Processing carried out experiments to test the theory. They started off by printing out four different colored papers: Dark yellow, dark blue, light yellow, light blue. The reason they used the different shades were to test if dogs actually used brightness to distinguish between items. The scientists proceeded to pair the dark yellow and light blue sheets together and the light yellow and dark blue sheets together. They were placed in front of two food bowls placed inside of locked boxes. After, they unlocked one of the boxes and put the dark yellow paper in front of the box which held a piece of raw meat. There were multiple trials and each one involved eight different dogs, varying of breed and size, given the opportunity to attempt to open one box before being removed. The results were that it only took the dogs three trials to learn which colored paper was in front of the box with the raw meat.
So in conclusion, dogs CAN see in color, even though this color vision is limited. Dogs only have 1,200,000 cones in their retina, as opposed to humans who carry 6,000,000. Humans can see red, blue, green and yellow, and dogs can only see blue and yellow. This is equivalent to what a human who is color blind might see.
Fun Fact: If you have ever seen any dog competitions or watched them on TV, you will notice that many of the obstacles are usually blue and yellow, now you know why!
Here is a video explaining things further
Sources: http://www.dailymail.co.uk/sciencetech/article-2374872/Dogs-CAN-colour-Scientists-dispel-myth-canines-black-white.html
http://www.merckmanuals.com/home/eye-disorders/biology-of-the-eyes/structure-and-function-of-the-eyes
I have two labs at home and I always found it so weird that the could only see in black and white. I always pictured what it would be like ( would it look like an old movie?). So, I found it really interesting that you blogged about this! The fact that they can’t see full color and only as much as a color blind human is fascinating to me. The fact that they can see color at all amazes me!!
Two scientists, Murphy and Miller, “note that green, orange, red and yellow probably look like different yellowish hues to the dog, while blue-green, blue and violet look like various shades of blue-gray. That makes sense when we consider dog ancestors probably didn’t need to see red colors, and dealt with the blues, greens and shaded browns and grays of hunting prey through vegetation.”
I think that gives us some good reasoning as to why dogs have red-green color blindness , don’t you?
http://www.colormatters.com/color-matters-for-kids/how-animals-see-color
This link shows comparisons of how we see colors vs. how dogs and other animals see colors
This is a very interesting topic to me! I absolutely love dogs, I have two of them at the moment and I adore them! Because I like dogs so much, the saying that dogs can only see black and white has always captured my intention, but I have never looked deeper into it. It is very cool to learn that dogs to actually see in color even though it is not as intensively as humans do! This really opens me eyes and makes me realize that my puppies do actually see the color of some things and that makes me happy! Another experiment that would be interesting to see would be to see how various other animals see in comparison, namely cats. Because cats are very good hunters it would be interesting to find out more about their vision!