Can Dogs see Colors?
- Posted by Daniel Flück on February 27th, 2007 filed in Animals
The question if dogs are colorblind, specifically red-green colorblind or if dogs only see shades of gray is raised among dog owners quite often. Even on the internet the question concerning dog vision is discussed controversial. But there is a simple answer to that question which I would like to share with you supported by some scientific resources.
Actually there are two distinct questions which I would like to ask, answer and set in relation hereafter:
- Can dogs see colors? — Answer: Yes
- Are dogs colorblind? — Answer: Yes
Let me explain this two answers to you a bit more in detail.
Dogs can see colors
Dogs not only see in shades of gray but also can see distinct colors contrary to what most people belief. About one hundred years ago some scientific tests were made to find out more about the color vision of dogs. But these tests weren’t that scientific as they thought and the researchers concluded only that color vision doesn’t play a part in the daily life of a dog.
Only about 90 years later distinct researches have shown that dogs can perceive colors. Neitz, Geist and Jacobs researched in 1989 the color vision of domestic dogs and found the following facts:
- Dogs have two different color receptors in their eyes and therefore are dichromats.
- One color receptor peaks at the blue-violet range, the other at the yellow-green range.
- Conclusion: Dogs are green-blind which is one form of red-green color blindness also called deuteranopia.
This results were support by later researches of Jacobs with colleagues in 1993 and Miller and Murphy in 1995.
Dogs are colorblind
This directly leads us to the second question concerning the color blindness of dogs. Colorblind doesn’t relate to not see any colors but describes the fact that you can’t see the same color range as somebody with normal vision. Because of that any kind of color vision deficiency is called color blindness. Therefore dogs are colorblind because of their dichromatic color vision.
Colors dogs can’t distinguish
Actually the color spectrum made up of wavelengths of light is the same to all of us. Only the perception of those colors can be quite different. As dogs only have two different color receptors in their eyes they have problems to distinguish certain colors:
- Red — Orange — Green
- Greenish Blue — Gray
- Different shades of Purple
The list is not completed and there are a lot of different shades which can’t be differentiated if you are colorblind. And the conclusion is dogs can see colors but are at the same time colorblind.
More facts on the vision of dogs can be found in the book Handbook of Applied Dog Behavior and Training, Vol. 1: Adaptation and Learning
September 9th, 2007 at 9:42
Hi Daniel
I’m just a novice but I have difficulty in considering dogs to be colour blind. Because they are dichromats, that only means that a typical dog sees differently to a typical human. Wouldn’t it be more appropriate to consider a dog to be colour blind if it only had a single type of cone? Further, if you do consider dogs to be colour blind, wouldn’t you also have to consider almost every human with normal S M L cones to be colourblind as there are some animals (and humans) that are tetrachromats?
Any comments?
Regards
Ewen
September 9th, 2007 at 15:52
Ewen, you are definitely right. There are even animals which can see ultraviolet and therefor all humans should be called colorblind compared to them.
When talking about color blindness we take the most intuitive interpretation of those words. This means, we call everybody (and every animal) colorblind, if they have less color vision than a human being with normal (trichromat) color vision.
October 8th, 2007 at 4:12
this was very helpful but i dont like it
November 24th, 2007 at 12:48
Hi Ben
I’m not quite sure what you don’t like, particularly as you say the response is helpful. Can you be more specific?
I think Daniel’s interpretation is probably the most reasonable one we can take. We always seem to judge based on our own experiences.
Regards
Ewen
November 24th, 2007 at 13:01
Hi Daniel
I’m intrigued by the way in which we try to accurately represent images with primary colours. While we trichromats seem to be quite able to do this with three primary colours, I would assume that tetrachromats would not see an image created with three primary colours as being an accurate representation of the real thing. I can’t find anything on the Internet that discusses this, and in particular, whether RGB and CMY images of the same object are seen as equivalent or different by tetrachromats.
I presume that a tetrachromat needs four primary “colours” to accurately represent an image and since no pigments represent UV, the only way a tetrachromat can accurately represent an image is electronically.
Do you have any references that you think might throw some light on this topic. (Sorry about the pun!)
Regards
Ewen
November 25th, 2007 at 17:51
Ewan, very interesting thoughts you are sharing here with us. Unfortunately I also haven’t any reference I could pass on to you.
But I agree with you. Our visual color world is just limited to a trichromatic color perception. What about a decachromat (a not existing person with ten different color receptors). She would be able to distinguish not only up to 150 different hues but let’s say 100′000 different hues. And this definitely wouldn’t fit in our color systems.
December 6th, 2007 at 6:11
Hi Daniel
Thanks for your website. You’ve stirred old thoughts that have been dormant for some years and made me start thinking about these things again. My line of thought is almost certainly not what you intended when you first wrote the article but I found it very worthwhile.
What I’m now looking at is colour recognition by artificial devices and methods of representation. Thank goodness for the Internet.
Best wishes for your site and to all associated with it.
Cheers
Ewen
March 18th, 2008 at 17:11
heyyy daniel,
your website helped me alot!
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