A Dog’s Vision
You’ve always been told dogs were color blind, thought a dog’s vision is built to see the world in black and white, right?
Unlike the old belief, dogs aren’t actually color-blind. No, they can’t see the full spectrum we can; unless new evidence has arisen since last time I checked, dogs are able to perceive Yellows and Blues.
How can we tell? Whereas physical tests have been conducted, the absolute best way is to examine the cells responsible for vision themselves, and their similarities to ours. You’ve heard of the ‘Rods and ‘Cones’ in the retina of a human eye? Well, dogs have them too, but in different quantities. This can tell us a lot about how they see!
In both humans and dogs, Rods detect motion and are responsible for night vision. A dog’s retina is dominated by rod cells, which makes a lot of sense- having evolved to detect small, rapid movements of prey.
Dogs also have a mirror-like membrane called a tapetum lucidum at the rear of the eye (which humans don’t) helping them with low light vision.
In both dogs and humans, cones are responsible for color perception and details of objects. Whereas we contain three types of cones, a dog’s eye contains just two. Current scientific belief indicates dogs detect hues of yellow and blue, which makes perfect sense! How many reds, greens and purples existed in the great tundras of the early north? Remember, these are abilities that likely didn’t change much since the early days of man’s existence.
As far as perception, dogs are said to have a 20/80 to our 20/20; they can see at 20 feet what we can see at 80. In this way, dogs are very near- sighted.
What This Says
So, again- what does this tell us?
- We already know a dog’s vision is built to pick out small, rapid movements; that clearly supports their hunting ability.
- They are able to see well in low light- which makes a lot of sense, since their ancestors (wolves) did a lot of hunting during the dusk hours.
- They aren’t believed to be able to perceive green, but can perceive shades of blue. So the area they originated from probably didn’t contain much green, but likely a whole lot of blue. Which again makes perfect sense, since the area we believe early wolves to originate from contained just that.