Do dogs see in black and white? How do we know?

Erik Mahler

Contrary to popular belief, dogs do have some colour vision, though theirs is undoubtedly different to the vision of humans. In the human eye there are two types of photoreceptors: rods and cones. Rods help us to determine differences in brightness and darkness, while cones are sensitive to colour. We have three types of cones: some are sensitive to red light, some are sensitive to green and some to blue. Dogs have more rods than humans, but less cones. Rods need less light to work, and this accounts for dogs having better night vision than humans. Humans rely more on cones, and differences in wavelength are harder to detect when there is less light, hence why we don’t see very well in the dark. Dogs are said to have dichromatic vision – they can only see a part of the range of colours which are in our visible spectrum. It’s thought that dogs can see different shades of yellow and blue as they have cones which correspond to being able to detect these wavelengths of light.