Are dogs colour-blind?

Have you ever wondered if your dog sees things the same way that you do? Maybe they see in black and white rather than in colour or see some colours but not others. Read on to discover the truth of the matter.

---

For many years, it was thought that dogs only saw in black and white. While that theory has now been disproved, it’s true that dogs don’t see colour in exactly the same way as we do. These differences affect how your dog perceives the world, and might even make you rethink the colour of toys that you choose for your dog!

How dogs’ eyes are different from humans’ eyes

Before we dig into the science between the differences in human and canine vision, let’s look at the two main types of light-sensing cells found within the retina:

• Cones: control colour perception and work best in bright light conditions
• Rods: detect movement and work best in low light conditions

Dogs’ eyes have more rods and fewer cones, which makes sense given dogs are descended from wolves and would have hunted fast-moving prey during dusk and dark. Dogs also have a larger lens and eye surface than humans. They also have a reflective membrane, known as a tapetum, which helps them see better than us in the dark. It’s also the reason their eyes ‘glow’ when the light hits them, or in flash photography!

In contrast, humans’ eyes have more cones and fewer rods, so while we can perceive more colours than our dogs can, we can’t see as well in the dark, or sense movement as quickly.

Why are dogs colour-blind?

The human eye picks up red, green and blue. This trichromatic vision means we can see a range of colours across the visible light spectrum. In comparison, dogs can only perceive yellow and blue. This means dogs have what’s known as dichromatic vision.

So although dogs aren’t completely colour-blind, they can’t perceive reds and greens in the same way that we can. Scientists think that they essentially see the world the same way as someone with red–green colour-blindness.

Are all dogs colour-blind?

The anatomy of all dogs’ eyes is the same, meaning they all perceive colour in the same way, and can’t see reds and greens as well as humans can. If you want to experience how your dog sees the world, the image processing tool Dog Vision allows you to upload a photo and strip away the colours your dog can’t see.

Your bright green lawn will look like a muted grey-green, and those bright red, pink or purple toys will appear grey or pale yellowy brown. For dogs, toys in these colours can be extremely difficult to discern from a green background – such as your lawn!

What colours are best for dog toys?

Ever wondered why agility equipment is almost always coloured blue and yellow? Now we know those are the colours a dog sees best, it makes complete sense! You can also choose dog toys with this in mind. Bright blue or yellow toys are much easier for your dog to see, as they’ll stand out against their surroundings.

If you’re practising advanced recall training, wearing a blue or yellow top can also make it easier for your dog to spot you from a distance! It’s also advised to have your dog’s eyes checked at least annually to stay on top of optical healthcare.