Are cats colour blind?

If you’re like most cat owners, you probably have a basket full of brightly coloured toys for your cat to play with. Fuzzy mice in different shades, balls with tiny bells in them for batting around, colourful feathers to chase—but do cats actually see all of these different colours? Are the vibrant hues just an advertising gimmick to entice owners to buy, or do they truly catch your cat’s eye?

How do cats see?

The answer to this question lies in the anatomy of the feline eye. The formation of a visual image starts with light rays entering the transparent cornea at the front of the eye. The light rays travel through the gel-like liquid that fills the eyeball until they hit the retina lining the back of the eye. Within the retina are receptors for vision—rods and cones.

When rods and cones are stimulated by light rays, they transmit an impulse to the brain that’s interpreted as a visual image. The cat’s brain then sees whatever she is looking at. Although rods and cones are both light receptors, they allow for different types of vision.

Rods are particularly sensitive to light, and allow for vision in low-light levels. They produce a coarse image in shades of grey, much like what you see when you are walking through a dark room. Cones are sensitive to color and detail. They produce an image that is sharp, detailed, and contains vibrant colors in various hues of the color spectrum.  

How are your cat’s eyes different from yours?

 Cats and other predators are designed to hunt for their survival. Cats are most active in the early morning and evening, when light levels are low. It’s more beneficial for them to be able to see in the dark than to see vibrant colors, so the retina of the cat’s eye contains a greater proportion of rods than cones. In fact, according to Live Science, your cat’s eyes have eight times as many rods as your eyes. This allows her to see a small mouse scurry across her path in the twilight hours.

Humans, in comparison, have 10 times as many cones as our feline friends. We’re able to see vibrant colors and images with sharper detail, but we don’t have very good night vision. The fewer cones in your cat’s eyes are most sensitive to wavelengths of light in the blue-violet and the yellow-green range. This allows her to see blue, yellow, and green fairly well. The image the cat’s eye produces during the daylight contains these colors, but the colors are not as vibrant as those seen by the human eye.

What is color blindness?

Color blindness typically refers to an inability to distinguish some colors from others. According to the National Eye Institute, the most common type of color blindness to affect people interferes with the ability to distinguish green from red. A second type does not allow people to distinguish blue from yellow. A third, much rarer, type called monochromatism only allows people to see black and white. Since a cat’s cones are most sensitive to blue and yellow wavelengths of light, they do not see colors like red, orange, or brown. They are similar to people with red-green color blindness—red hues likely appear as the color green to your cat.

What do cats see?

Research tells us the image seen by your cat likely contains muted shades of blue and yellow, mixed with varying shades of grey. Cats also have a broader range of vision than humans do, although they do not have the visual acuity of their human owners. While we can see items in sharp detail 100–200 feet away, cats can only see clearly for about 20 feet. All of this is a fair trade-off for the ability to see slight movement of prey in the dark.

How can I stimulate my cat’s vision?

Since your cat’s vision is designed to make her the ultimate hunter, you can plan stimulating activities that will activate her inner predator. Try these ideas to keep your cat’s senses invigorated:

  • Play a laser pointer’s light across floors and walls through your house. The quickly moving light will be picked up by your cat’s rods, prompting her to chase it like she would a prey animal.
  • Ditch the boring food dish. Instead, hide your cat’s dinner in multiple places around your home to bring out the natural hunter in her. You can also purchase indoor hunting feeders or puzzle toys that your cat has to solve in order to score her next meal.
  • Play videos for your cat while you are away for visual and auditory stimulation. Search for footage of birds flitting around, colourful fish swimming in a tank, or mice scurrying around.
  • Treat her to some fresh catnip. When your cat smells the oils produced by the plant, she will experience increased activity and ecstasy-like enjoyment.