Cats are incredibly stealthy. Even when all the lights are turned off, cats run, jump and play without hesitation. Meanwhile, pet parents are tripping over cat toys and fumbling through the dark!
When you look over at your crazed kitty, her eyes may glow an eerie dim blue-yellow light even when most lights have been turned off. So what is the reason for this glow, and why do cats have a fantastic ability to see so well in the dark?
Can Cats See in the Dark?
Yes. Cats can see in the dark and have much better night vision than humans do. Humans need six times more light than cats to see in the dark. Cats can see well when it is dark, but there needs to be some light.
Although cats can be active at night, cats are not nocturnal animals. Instead, cats are crepuscular. Crepuscular animals are most active at dusk and dawn. Cats evolved from desert animals, and dusk and dawn are the coolest times of the day. For this reason, cats are most active at those times.
How Do Cats See in the Dark?
Light enters an eye through the cornea, the pupil, and the lens. A cat’s cornea, or the clear part of the front of the eye, is larger than other species and can catch more light when it’s dark outside. A cat’s pupil, or the black center of the eye, can open very wide and round and allow the lens to catch more light. A cat’s lens, or the clear curved structure behind the black pupil, is also larger to supply more light to the retina behind it.
A cat’s retina, found at the back of the inside of the eye, has a special layer called the tapetum lucidum. This layer is made up of reflective cells that allow light to bounce off the back of the eye, increasing the chance the eye will absorb the light. Think of the tapetum as a mirror reflecting beams of light. This layer is the reason cat eyes appear to glow in the dark! Cat eyes allow six times more light to be processed by the retina than humans, giving them excellent night vision.
Photoreceptors called rods and cones sit in the retina. Rods improve vision when it is dark and detect movement, while cones are responsible for seeing color and sharp images in the daytime. Compared to other species, cats have way more rods—three times as many as humans. Rods are also responsible for detecting movement, which explains why cats are excellent hunters at night. However, the number of cones in a cat’s eye is lower, so cats cannot see as many colors or very well in the daytime.
How Well Can Cats See in the Dark?
Cats can see very well in the dark. Based on the high number of rods and the tapetum layer in their eyes, cats can see better at night than humans, dogs, and many other animals. The trade-off is that cats cannot see well in daylight. Cats have many more rods than they do cones, which are necessary to see clearly in daylight. Also, a cat’s eyes are so reflective that when light enters the eye, it bounces back and forth until it lands on receptors to take the signal, resulting in less accurate vision in the daytime.
Surprisingly, there are other ways cats can “see” without using their eyes. Their sense of smell, hearing, whiskers, and paws can be used to navigate without seeing well. Whiskers sense vibrations or changes in air current, which helps cats determine the size, shape, and speed of moving objects near them. Their paws feel for vibrations on the ground, which also assists cats when it is dark.
Cat Night Vision: Other Interesting Facts
- Cat’s vision equates to 20/100. Their sharpness of vision is less than dogs or humans.
- Cats can see yellow and blue colors, but red and green are viewed as various shades of gray.
- Vocalizing at night is common in cats when they become senior, and it is often tied to medical concerns such as loss of vision or hearing.
- A cat’s tapetum layer reflects 130 times more light than human eyes.
- Cats can see up to 120 feet away, but many cats cannot see things within a foot of their nose.