Are Dogs Color Blind? Scientists Claim Canines Use Color To Distinguish Objects In New Study [REPORT]
It was long thought that man's best friend viewed the world as Kansas farm girl Dorothy Gale did before her journey to Oz - in dull shades of gray. But research into dog sight has proven that's not the case. Not only do dogs see some color, they also use color to distinguish between and identify objects, says a new study from Russia.
According to The Daily Mail, a team of researchers from the Russian Academy of Sciences tested the sight of eight dogs of varying sizes and breeds and found that canines have a limited color range in their vision. This is because dogs have about 20 percent of the color-perceiving photoreceptor cells, called cones, that humans have.
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"While human eyes have three 'cones' that detect color and can identify red, blue, green and yellow light; dogs only have two," the Daily Mail reports. "This means dogs can distinguish blue and yellow, but not red and green."
To test the dogs' visions, the researchers at the Academy used different colored paper to distinguish between various food bowls, some of which contained raw meat, kept inside locked boxes. After just a few trials, the dogs learned which color paper was placed before the box containing the desired treat.
"Our results demonstrate that under natural photopic lighting conditions color information may be predominant even for animals that possess only two spectral types of cone photoreceptors," one of the researchers said.
Scientists have known for some time that dogs' vision isn't limited to black and white. In 2008, Psychology Today reported that dogs do see colors, it's just that the colors they see are not as vibrant nor as varied as those seen by humans. From Psychology:
The eyes of both people and dogs contain special light catching cells called cones that respond to color. Dogs have fewer cones than humans which suggests that their color vision won't be as rich or intense as ours. However, the trick to seeing color is not just having cones, but having several different types of cones, each tuned to different wavelengths of light. Human beings have three different kinds of cones and the combined activity of these gives humans their full range of color vision.
Instead of a color spectrum made of violet, blue, blue-green, green, yellow, orange and red, dogs see a color spectrum that includes dark blue, light blue, gray, light yellow, darker yellow (almost brown), and very dark gray.
To dogs, anything green appears as white, and anything red looks black. So if you want your canine friend to be able to see his or her favorite chew toy in all its bright glory, make sure to buy it in yellow or blue.
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