Cats can see a wide range of colors, but not quite as many as humans. Their color vision depends on the variety of light-sensitive cells called cones in their eyes. Here’s a quick overview of a cat’s color spectrum and how it compares to human vision.
Cats Have Fewer Color Cones Than Humans
Humans have three types of cones that allow us to see the colors red, green, and blue. The combination of signals from these cones allows us to perceive the full spectrum of visible light. Cats, on the other hand, have only two types of cones – one for blue and one for yellow/green. This means cats can’t distinguish between red and green hues.
So while humans are trichromats (having three color cones), cats are dichromats (having two color cones). This gives cats a more limited color spectrum than humans.
Cats See More Blue and Green Tones
Although cats can’t see the full range of colors, their two-cone vision system allows them to perceive blue and green tones very well. Their eyes have six to eight times more rod cells compared to humans, which are more sensitive to dim light and motion.
The abundance of rod cells comes at the expense of having fewer overall cone cells for color vision. But the cone cells cats do have are most sensitive to blues and greens. These wavelengths stand out more to cats and appear brighter.
Red Looks Similar to Green for Cats
Because cats lack dedicated red color receptors, they can’t distinguish between reds and greens. Red hues appear more green or neutral to a cat. So a red toy and a green toy would look very similar to a cat, while they are very distinct to our eyes.
This is why cat toys and products designed specifically for cats often use blue or green colors over reds. Cat vision sees these tones more readily.
Purple and Yellow Stand Out to Cats
Although red looks muted to cats, they can still see the other end of the spectrum quite well. Violet and purple hues contain enough blue wavelengths for cats to perceive. Yellows also stand out since they strongly stimulate cats’ green color cones.
So while cats miss out on seeing vibrant reds, they still react to high-contrast yellows and interesting purples more noticeably.
Cats See Some Ultraviolet Light
Humans can see light wavelengths between approximately 400-700 nanometers. Cats have a slightly wider field of vision, extending into the near ultraviolet spectrum from 300-700 nanometers.
This means cats can see some UV light that humans cannot. Certain patterns and traces on flowers may stand out vividly to cats while being virtually invisible to our eyes.
Contrast Is More Important Than Color
Since cats don’t have as full color vision as people, contrast is more important than color when it comes to holding their visual interest. Bold patterns and clear outlines are more important than the specific hue or shade.
High contrast is also beneficial for cats with declining eyesight due to age. Simple and defined shapes with distinct edges can compensate for some loss of visual acuity in senior cats.
Here is a Comparison of Human vs. Cat Color Vision
| Color | Human Vision | Cat Vision |
|---|---|---|
| Red | Vivid and distinct | Dull/neutral, hard to distinguish from green |
| Green | Clear and moderately bright | Very bright, visible shades stand out |
| Blue | Crisp and moderately bright | Extremely bright, very visible |
| Yellow | Bright and vivid | Clear and stimulating to color receptors |
| Purple | Moderately bright and distinct | More muted but visible due to blue tones |
| Ultraviolet | Invisible | Partially visible at near-UV wavelengths |
As shown in the table, cats miss out on seeing bright reds but gain enhanced perception of blues, greens, and some UV light compared to humans.
Cats Rely on Other Senses More Than Humans
In addition to their specialized vision adapted for night hunting, cats also rely heavily on other senses:
- Hearing – cats can hear frequencies up to 64 kHz, well above the human range
- Smell – cats have around 200 million scent receptors compared to 5 million in humans
- Taste – cats have fewer taste buds than humans but a strong sense of smell that contributes to their flavor perception
- Touch – cats use tactile input from their whiskers (vibrissae) to navigate environments
So while cats may lack some of the rich color vision humans enjoy, their world experience is built on a different sensory framework that works extremely well for them.
Cats’ Eyes Glow Due to the Tapetum Lucidum
One distinctive aspect of cat eyes is that they often seem to glow or flash in low light conditions. This is due to a reflective layer behind the retina called the tapetum lucidum, which allows cats to make better use of low light.
The tapetum acts like a mirror, bouncing light that passes through the retina back into the light receptors for a second pass. This gives cats’ photoreceptors two chances to capture photons in dark environments.
Humans lack a tapetum lucidum, so our eyes do not reflect light in this way. The glowing eyes of cats at night are a visible indicator of this difference.
Cats Can See Well in Low Light Due to Large Pupils
In addition to having a reflective tapetum lucidum, cats’ eyes are exceptionally adapted for nocturnal hunting due to their large pupils. The pupils open wide at night to let in as much light as possible.
Cat pupils function within a range of 1.5 – 8 mm in diameter compared to 2 – 4 mm for human pupils. When fully dilated, cat pupils can open over 130 times wider than humans’ in dark conditions.
This combined with the tapetum gives cats excellent night vision up to 6 times better than people in low light. But it comes at the cost of reduced daytime visual acuity.
Conclusion
While humans enjoy trichromatic vision sensing the full spectrum of visible light, cats see a more limited range with just two types of cone photoreceptors. This gives cats enhanced perception of blues and greens but an inability to distinguish between reds and greens.
Cats also pick up some ultraviolet light that humans can’t detect. And their eyes are extremely adapted for nocturnal hunting thanks to the tapetum lucidum and large dilating pupils. So even though cats have fewer color detection cells, their eyes are specialized for the environments and tasks cats are evolutionarily adapted to.
So next time you catch a glimpse of your cat’s eyes flashing in the night, you’ll know it’s because they have visual abilities tuned for the environments where cats thrive. Their different spectrum vision reveals cats experience the world in a unique way.
