Are Dogs Really Colour Blind?
Have you ever wondered how dogs see the world? We already know they have a phenomenal sense of smell and hearing. But does that also apply to their vision too? Or, as common urban myth asserts, are dogs actually colour blind? That’s what we set out to find out.
Is the world of dogs just black and white? Or do dogs see in technicolour?
If you’ve ever wondered how your dog perceives the visual world, read on to find out.
What colours and shades do dogs see?
Dogs aren’t actually colour blind. At least not in the way most people think about it. They don’t see the world in black and white. But they still don’t see the spectrum of colours humans see.
Well, to understand that, you first need to appreciate how sight works. In the retina – the layers of cells at the back of the eye – there are two visual receptors: rods and cones.
Rods work in low-light situations, processing a black and white image. It’s the cone cells that add colour to the picture. Humans are trichromatic, meaning we have three different types of cone cells: blue, green, and red. Dogs, however, are dichromatic, seeing the world using only two colours: blue and yellow
That means that while dogs do see colours, they’re capable of seeing substantially fewer colours than humans. Even worse, dogs cannot appreciate all the tones and shades humans can perceive.
So, the world to a dog is most likely just shades of blue, yellow, and grey.
How does a dog’s vision differ from other people’s?
In people, a dog’s vision is equivalent to a form of colour-blindness. Indeed, dogs are most similar to red-green colour-blind people. Meaning, they’re excellent at distinguishing between blues and yellows but struggle with reds and greens.
To properly appreciate the difference in vision, picture two spectrums.
First, see the full rainbow spectrum of colour, from pink, through red, orange, and yellow into green and eventually deep blue and purple.
In contrast, the spectrum begins as dark grey to a dog, fades to a bright yellow, then white, followed by a gradually darkening shade of blue.
Thank you for your interest!