Posted by: courtneygrapperhaus | May 5, 2015

What can your dog actually see? and do we really know?

The question has often been raised about what dogs see versus what their human companions see.  Many people believe that dogs only see the world in black and white. I was one of these people until my husband and I adopted Dorothy. After witnessing her pick out the orange ball from the other colored balls several times, we both came to realize that dogs must see color to some extent. That prompted me to do some research.

Dorothy through a human's eyes VS Dorothy in

Dorothy through a human’s eyes VS Dorothy in “Dog Vision” (image created at https://dog-vision.com)

Aside from just 2 articles, one published in 1995 and one in 2013, I was surprised to find very little scholarly research on the subject. “Because a multitude of factors are involved in the sensation of vision, the outwardly simple question of how well dogs see is, in reality, quite complicated.” (Vision in Dogs by Paul E. Miller, DVM and Christopher J. Murphy, DVM, PhD).  Even though just a few studies have taken place, research has lead to some common conceptions among scientists.

We know that different breeds of dogs have different vision just based on the fact that their eyes are different sizes, shapes and locations. A lot of this has to do with what the breed was “born to do”. Wikipedia states that “many long-nosed breeds have a “visual streak” – a wide foveal region that…gives them a very wide field of excellent vision. Some long-muzzled breeds, in particular, the sighthounds, have a field of vision up to 270 degrees (compared to 180 degrees for human). Some broad-headed breeds with short noses have a field of vision similar to that of humans.” In addition to the variances between breeds, there is a difference amongst dogs of the same breeds, just as humans of the same ethnicity have different vision. Visual acuity in dogs is thought to have a Snellen fraction of about 20/75. That means, if a person with normal vision acuity (20/20) stood 75 feet away to see an object, their dog would have to stand 20 feet away to see the same object.

Dogs only have 2 types of cones in their eyes. Humans have 3. This means that a dog’s ability to see color is less than a human’s. Most scientists compare a dog’s color vision to that of a human who is red-green color blind. Until a 2013 study published in the Proceedings of the Royal Society B, many researchers believed that dogs respond to brightness variation in colors more than the colors themselves. The new study concluded that dogs can perceive the difference in both colors and brightness, and perhaps that color is more of a deciding factor. The study only consisted of a small group of eight dogs so it is difficult to say how much the findings represent dogs as a whole, but it is still interesting research. You can view the entire article at http://rspb.royalsocietypublishing.org/content/280/1766/20131356.

Dog Color Spectrum

Dog’s ancestry and breeding has prepared them to be great hunters and their sight has evolved accordingly. For example, if you have ever had a dog, you probably noticed that they respond to moving objects much more than they do stationary ones. Dogs can also see better than humans when it comes to low light environments (like dawn or dusk) and they have remarkable night vision. We all know that dogs, like humans, use all of their senses. Our senses help us to determine what is around us. One major difference in humans and canines is that while our dominant sense is vision, theirs is smell. So, it stands to reason that dogs rely much less on their sense of vision and that the differences in our vision versus theirs has no real meaning to them.

All in all, we still have a lot to learn about dog vision, and we will probably never know the whole story.

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Responses

  1. Reblogged this on Amcon GAZEtte and commented:

    Did you go to Pet Palooza at Purina Farms this weekend? This blog may give you insight into how your dog saw the festivities.


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