Dog Vision

Dog vision - what do our friends see?
There are some common misconceptions in the canine-lover's world about how well dogs see.
In fact, for their purpose, dog's have quite useful optical tools at their disposal. While it is true dogs usually depend more on their sense of smell, evolution has provided them with some quite complimentary eye-sight.

A myth: Dogs are color-blind....not!

It is a common to hear people say dogs are color blind, and that simply is not true.
What is true is that dogs eyes have only two cones each, whereas the human eye has three. Thus, dogs are "dichromatic" while you and I are "trichromatic".
Here is a nice comparison of the color spectrums visable to humans and dogs:

Basically this means that dogs cannot see green or probably red. But they can still see violet, indigo or blue. So a dog has difficulty differentiating between objects that we see as, green, orange, yellow or red.
Think about that when you choose which color ball to toss to pooch in the back yard. He's going to have problems finding a red ball that has found it's way into long green grass!
Interestingly, however, the fact that dogs are dichromatic makes them much more sensitive to different hues of grey, meaning they can see much better than we do at night or near night.
So don't feel so bad for him.
On the left is a picture of the way we would view the puppy, and on the right, how the same picture would look to a dog:


Read more about dog color blindness (or lack thereof), here.

While our eyes are built to detect both color and light, dogs have a greater need to see light than color. Their eyes contain more rods (the light detection pieces of the eye) than cones (the color detectors) to allow them to see fairly well even in darkness.
In addition to their night vision, dogs also have bigger pupils than people. This helps them track moving objects for longer distances without having to move their heads. And there was me thinking that my dog just couldn’t be bothered!

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