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What’s the single biggest myth you know about dogs? There are certainly many to consider, and several of which you might not even realize are myths. For instance, dogs don’t ONLY eat grass when they are sick, dogs’ mouths aren’t cleaner than the human mouths, and a dog’s age isn’t quite equal to seven human years. But the single biggest canine myth of all is almost certainly the misconception that dogs are all completely incapable of seeing color.
Is it true? In short, no. Modern science has debunked this time and time again, finding that dogs are not color-blind in the way that many believe, which is that they see the world completely in black and white (or even in grey-tinted tones). In reality, dogs are only partially color-blind, meaning they can see colors, but they perceive them more like humans with red-green color blindness do as opposed to the majority of us with “normal” eyesight.
It all starts with rods and cones in the eyes. Rods help creatives (human and canine alike) recognize how bright or dim something is, which helps more with the black and white spectrum of things. Dogs have highly receptive rods, which means they have clear eyesight when viewing objects on the light spectrum. To them, dark tints are extra dark and light tints are extra light, hence the association with black and white.
Cones, on the other hand, help us all identify color. Because dogs only have two cone cells in their eyes (“dichromatic”), enabling them to see just shades of blue and green. Humans, on theother hand, have three cones (“trichromatic”), which lets them see red as well. For regular human eyes, blue, green and red are the basic primary colors that all other colors are made from (with the occasional assist from black and white, of course).
Now, imagine taking red completely out of that combination. A color like purple, which is made from a dense mixture of blue and red, would suddenly look vastly different—virtually unrecognizable to us humans as “purple.” But, thanks to the remaining red, a dog would still be able to perceive some color there. In fact, dogs recognize red as more of a brownish-black, much different than what a healthy human eye would perceive. Meanwhile, colors like orange and green appear as yellow, and the colors they are best able to distinguish between are yellow and blue. This is why so many canine agility courses are vibrantly painted with these two colors.
The basis for this myth is highly disputed and, basically, no one really knows for sure where it initially came from. One theory in particular, that has gained some amount of acceptance, claims that the myth originated and became prominent in the 1920’s due to the existence of a widely circulated scientific article claiming dogs (and cats) were completely incapable of perceiving color. This theory, and the research conducted, was eventually questioned by scientists decades later, who promptly dispelled the research as archaic and concluded the findings were inaccurate.
Another relatively popular origin story claims the myth originates from one Will Judy, the founder of National Dog Week. He was supposedly the first to claim dogs could only see single shades and tones, all in grayed-out tints, and even detailed his hypotheses in a famous 1937 manual. Again, however, there is no way to confirm this was actually the very first instance of this misconception being spread to a widespread audience.
Fortunately, it turns out that not all dogs are hindered by complete color-blindness after all. But that doesn’t mean there aren’t other eye-related health issues that could potentially compromise their sight.
Symptoms of impaired vision in dogs can range from the obvious to the unassuming. For example, if your dog isn’t eating right, it might be because he or she can’t find his or her bowl. Stress can also cause a loss of appetite, and eyesight issues can certainly be stressful. Other signs to look for are discharge, tearing, an inability to keep the eye(s) open, and unequal pupil sizes. These could all be potential symptoms of various canine eyesight issues such cataracts, corneal ulcers, infection, injuries from things like scratching or bumping into objects, and even tumors. If you notice any of these abnormal behaviors, contact your veterinarian right away!