Are Dogs Colour-blind?


Myself . 

By T. V. Antony Raj
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(Source: ScienceDaily.com)

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Question: Are Dogs colour-blind?

Answer: No, dogs are not completely colour blind. They have a dichromatic colour perception and so perceive a limited colour range when compared to the colour spectrum we humans see.

The dogs see more than just black, white, and grey. Most humans have three different colour sensitive cone cells in their retina (red, green and blue) while dogs have only two (yellow and blue). So, instead of perceiving the intensity of three colours like us, red, green and blue, the dogs perceive the intensity of only two colours: blue and yellow, similar to colour blindness in humans. So, basically, the canine colour field consists mostly of yellows, blues, and violets.

This does not mean that dogs can’t see green or red objects. While blue and yellow are the easiest for them to see, they perceive the intensity of red as different levels of grey.

Many think that dogs may be slightly near-sighted and have a visual acuity (contrast) of much less detail than we humans do and so objects at a distance may appear blurry to them. Studies show that most dogs have an eyesight equivalent from 20/50 to 20/75.  Due to of their ability to visually discriminate motion, they have been known to recognize their owners even at 800-900 meters distance. However, it is widely accepted that dogs do see better at night which is certainly an advantage and one that helps dogs a great deal.

The following video is a rough simulation of what a dog sees with its eyes.

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Now, if you begin to feel sad for your pet dogs, just remember that the dogs have an incredible sense of smell that basically lets it “perceive and sense” the world in different scents.

In the following video, the dog though green-blind perceives the intensity of the green traffic signal as a level of grey and makes us wonder whether the dogs can see all colours.

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