Are Cats Red-Green Color Blind? Can’t They See Red at All? What Colors Can Cats See? Do They Have a Preferred Color? How Do Our Eyes Differ from Cats’ Eyes? - The Differences May Surprise You.
As humans, we are omnivores. Our ancestors not only hunted but also gathered a large number of plants and berries, primarily during the daytime. Therefore, the ability to distinguish food by color is crucial for us. On the other hand, wild cats primarily hunt at night, eliminating the need for them to distinguish prey by color. As a result, a cat’s vision is primarily focused on night vision and capturing moving objects. The difference in the primary functions being carried leads to a big difference in color vision between us and cats.
Both humans and cats have two types of photoreceptive cells: cone cells and rod cells. Cone cells are primarily responsible for strong light and color, while rod cells are mainly responsible for weak light stimulation. Humans typically have three types of cone cells, which can identify various colors from the combination of three primary colors, and our visible light wavelength range is about 780-400nm.
However, cats only have two types of cone cells (though some researchers suggest there may be a third type, but in rare cases), and their visible light wavelength range is only about 450 nm to 556 nm. This leads to the fact that when cats distinguish longer-wavelength red color, they may only distinguish it based on brightness, but cannot see the true red color. (However, cats can distinguish between “red” and “green”).
At the same time, due to the difference in the number of cone cells, the color seen through a cat’s eyes is very different from the color seen through our eyes, and the saturation is also very different because the saturation seen through a cat’s eyes is lower.
When you and a cat observe the same scene, the difference might look something like this:
Left: what you see; Right: what a cat sees.
The absence of longer-wavelength colors such as orange and red, and the lower saturation of blue and green, are the main differences between our color vision and that of cats.
While it may seem unfortunate that cats can’t see red, researchers speculate that cats might be able to see something we can’t - ultraviolet light.
Ron Douglas, biologist at City London Metropolitan University, examined the eyeballs of various animals and found that the crystalline lenses of hedgehogs, dogs, cats, and ferrets allow ultraviolet light to pass through. However, scientists are still unsure what color a cat’s lenses would display when ultraviolet light passes through it (after all, we can’t see it with our own eyes). How the world appears through a cat’s eyes still requires further exploration by scientists.
Currently, there are two prevailing theories about what color cats prefer.
The more classic one is that cats favor the color red. Supporters of this theory argue: “Cats are carnivores, and the color of meat is red, so cats should be sensitive to the color of meat, hence red is a cat’s favorite color!” However, as we’ve mentioned before, cats can’t see the true color "red". When they are hunting, the importance of color is further diminished, but their superior senses of smell and hearing are their most powerful aids. Therefore, the claim that cats prefer red isn’t entirely convincing.
Some researchers, led by Lynn Buzhardt, believe that cats may prefer the colors blue and green, which they can see most clearly.
These researchers believe that cats see a shade of gray when they look at red, which their cones simply cannot recognize, and that this color lacks stimulation and should not be appealing to cats. There is some truth to both claims, but unfortunately, no one has done a more scientific experiment on cat color preference. Pet owners can give priority to the three colors of red, blue and green when purchasing toys on a daily basis, and as to which one a cat prefers, it can only be slowly observed in daily practice.