The Truth about Cats and Color. Do They Really Only See Black and White?

Introduction

Cats have a unique visual system compared to humans and other animals. While we see in full color, cats have dichromatic vision, meaning they can only see some colors. Understanding how cats see the world can give insight into cat behavior and help us better care for our feline companions. A cat’s vision allows it to effectively hunt, especially at night, but also causes some colors to appear washed out or indistinguishable. Examining the differences between human and feline eyesight reveals fascinating adaptations and helps explain why cats interact with their environments differently than we do.

Cats Have Dichromatic Vision

Cats have dichromatic vision, meaning they have two types of color receptors (cones) in their eyes that allow them to distinguish some colors, but not as many as humans. Humans have three types of cones, making our vision trichromatic. Cats’ cone cells absorb wavelengths in the blue-violet and green-yellow ranges, whereas humans have additional cones that detect red light.

Having only two cone types means that cats have a reduced color spectrum compared to humans. With dichromatic vision, cats can’t distinguish between certain colors in the red, orange, yellow, and green parts of the visible light spectrum. These colors appear similar or indistinguishable to cats. This is why cats can’t see the difference between red and green.

Overall, cats see a more limited range of colors than humans do. While we can see the full spectrum of visible light, cats are missing the ability to discriminate some colors that require input from red-detecting cones. So cats effectively see the world in a mix of blues, grays, and yellowish-greens. Their vision isn’t truly black and white, but it’s more muted compared to human color perception.

Sources:
https://www.wired.com/2013/10/cats-eye-view/
https://pubmed.ncbi.nlm.nih.gov/27720709/

Cats Can See Some Colors

While cats can’t see colors as vividly as humans, they do have some color vision, especially for blues and greens. According to VCA Animal Hospitals, cats have dichromatic vision. This means they have rods and cones in their eyes that detect only two primary colors – blue and green.

Cats’ eyes have six to eight times more rods than cones. The rods allow for excellent vision in low light situations, which is why cats can see so well at night. But it also means they don’t have strong color perception. The cones they do have are most sensitive to blues and greens.

So while cats can’t see the full spectrum of colors that humans can, they can differentiate between blue and green. Their world consists of muted versions of those colors. Scientists believe cats see blues and greens as shades of gray, from light silver to dark charcoal.

This is why cat toys and laser pointers often use blue and green colors. To cats, these stand out the best in their vision. So they are more likely to pay attention to toys that incorporate shades like blue, teal or lime green.

Cats Can’t Distinguish Red from Green

Unlike humans who have trichromatic vision and can perceive the full spectrum of colors, cats only have dichromatic vision. This means they have two types of color receptors (cones) in their eyes, compared to humans who have three. Cats are missing the red cone, which allows organisms to see warmer colors like reds, oranges, and pinks.

Without the red cone receptor, cats see colors from the green to violet end of the light spectrum, but they can’t distinguish between red and green hues. Instead, cats perceive reds and greens simply as shades of gray. So a red object and a green object would look identically gray from a cat’s visual perspective.

This is why cat toys and laser pointers use blue and green light rather than red. To a human eye, a red dot or toy stands out clearly. But because cats can’t distinguish red from other colors, a red laser pointer or toy would just blend into the background as a nondescript gray shape from a cat’s point of view.

So while cats can see shades of blue and green, reds and oranges appear as various tones of gray. Their vision is dichromatic, seeing the world in muted grays, blues, greens and yellows rather than the full spectrum of colors that humans perceive.

Cats Have Excellent Night Vision

Cats have a number of adaptations that allow them to see exceptionally well in low light conditions. Their eyes have a larger corneal surface and a larger pupil opening compared to humans and many other mammals. This allows more light to enter the eye and hit the retina, improving their ability to see in dim lighting (https://www.purina.co.uk/articles/cats/behaviour/common-questions/can-cats-see-in-the-dark).

Cats also have a reflective layer behind the retina called the tapetum lucidum. This acts like a mirror, reflecting light back through the retina and giving light particles a second chance to be detected by photoreceptors. This enhances cats’ ability to pick up more subtle light cues in darkness (https://medium.com/@penjourney/seeing-in-the-shadows-the-secrets-of-cats-nighttime-vision-62eba77f4054).

Additionally, cats have a high density of rod photoreceptor cells in their retinas compared to humans. Rods are more sensitive to light and motion than cone cells, so this allows cats to detect movement more easily in dark environments when cone cells may not pick up enough light.

Cats Rely on Motion and Contrast

Cats rely more on detecting motion and visual contrast than distinguishing colors. Their vision prioritizes perceiving movement over making out fine details. Cats have significantly more rod cells than humans, which are more sensitive to light and motion, but fewer cone cells that detect color. Their retina contains only about one sixth the amount of cone cells compared to humans.

This gives cats excellent night vision and ability to track moving objects in low light. However, it comes at the cost of discerning stationary objects and colors. Cats see about 6 times better than humans in the dark. Their retinas have a reflective layer that bounces back any light that passes through, allowing the light to stimulate the rods twice. This adaptation allowed cats to be efficient nocturnal hunters.

In addition to favoring motion over color, cats rely heavily on visual contrast. Their vision is attuned to detecting outlines, shapes and patterns that stand out, rather than a wide spectrum of colors. Strong contrasts in brightness, rather than hue, are most visible to cats. This again suits their needs as hunters to spot camouflaged or moving prey against complex backgrounds.

How Cats’ Vision Compares to Other Animals

Cats have very different vision compared to humans and other animals. While humans and primates have trichromatic vision and can see a full spectrum of colors, cats have dichromatic vision. This means they can only see a limited range of colors, similar to someone who is colorblind. Specifically, cats cannot distinguish between red and green shades. They see these colors as shades of gray [1].

Dogs also only have dichromatic vision, however their color spectrum is slightly different from cats. Dogs have more cone receptors for yellows and blues. So dogs may be able to distinguish certain shades, like yellow versus blue or purple, better than cats can [2]. But both cats and dogs see fewer colors than humans.

Birds, fish, reptiles, and amphibians may have tetrachromatic vision, allowing them to see an even wider spectrum of colors. For example, some birds can see ultraviolet light. So cats and dogs see a more limited range of colors than many other animals [2].

While cats don’t see a full range of colors, they have excellent vision in other ways. Their eyes are adapted for seeing at night and detecting movement. So a cat’s vision has both advantages and disadvantages compared to other animals.

Why Cat Vision Evolved This Way

Cats’ unique vision evolved to allow them to be highly effective hunters (1). As predators that rely on stalking and ambushing their prey, cats needed exceptional abilities to see in low-light conditions. Their elliptical pupils can open wide to let in extra light, and their retinas are packed with light-sensitive rod cells optimized for night vision.

Cats also developed enhanced motion detection compared to humans. While humans see detail best with their fovea, cats have a visual streak that detects fast movement extremely well (2). This allows cats to spot prey animals moving at night. Cats’ eyes are placed frontally, giving them depth perception to accurately judge distances when pouncing and catching prey.

Additionally, cats evolved heightened sensitivity to contrasts and edges. As ambush hunters, cats rely on seeing camouflaged or hiding prey against backgrounds. Their edge detection and ability to distinguish subtle contrasts, like a mouse against grass, gives cats an advantage.

In short, cats’ unique evolutionary adaptations like sensitive night vision, motion detection, depth perception, and edge sensitivity all provide major hunting benefits that aid their role as stealthy predators.

How to Test What Cats Can See

Scientists have designed several clever experiments to test cats’ ability to distinguish colors and see under low light conditions. In one study published in Vision Research, researchers trained cats to discriminate between hues and tested their wavelength sensitivity using a two-choice discrimination task (Clark et al., 2016). They found evidence for a spectral neutral point around 501 nm, indicating cats rely more on rod cells for color vision.

Other studies have examined whether cats can distinguish different colors at low light levels. In an experiment described in Nature, cats were trained to choose between two adjacent fields of perceptibly different colors (Daw, 1970). By systematically reducing the illumination, researchers showed cats could distinguish colors at light levels 100 times lower than humans. These behavioral experiments help demonstrate cats’ impressive ability to see color and motion under dim conditions.

Pet owners can also test their own cats’ vision at home. Simple experiments like placing different colored toys in a dim room can reveal how well cats distinguish colors in low light. Owners can also test cats with toys or treats hidden in tall grass to see if motion and scent are more important for hunting than color vision.

Conclusion

In summary, cats have dichromatic vision which means they have two types of color receptor cones in their eyes. This allows cats to see some colors including blues, grays, and greens, but they cannot distinguish between red and green hues. Cats also excel at seeing in low light conditions due to having a high concentration of rod receptor cells, allowing for excellent night vision. While cats do not see the full color spectrum that humans do, their vision is well adapted for hunting and survival. Their visual acuity may be more limited than some animals, but cats rely on other senses like motion and smell to expertly perceive their environment.

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