Based on your cat flying through the house in the middle of the night, you can rightly assume that cats have good night vision. While they can’t see in total darkness, they are better equipped than people to see in low light.
How Cats See
Like humans, cats have two types of photoreceptors in their retinas (the back part of the eye). Rod receptors are best at detecting light, and cone receptors are responsible for color and detailed vision. Since cats have many more rods than we do, they can see about seven times better than we do at night. In daylight, however, cats have less visual acuity than people. Interestingly, most cats are nearsighted.
Because cats have fewer cone photoreceptors than people, they are largely colorblind. Most cats can probably see blue, yellow, and green hues to some degree, but they are better at distinguishing shades of gray, which is important for hunting at night and during dawn and dusk.
Slit Pupils Aid Ambushes
A cat’s pupils are more slit-shaped than round like ours. These slit pupils help give the cat her “ambush predator” hunting ability under low-light conditions, as they can increase the amount of light that reaches the retina by 135 to 300 times when they fully dilate. In contrast, a human’s round pupil increases retinal light availability between 10- and 15-fold when it dilates. It is estimated that cats can get by with about 17% of the light a person would require in the same situation.
Cats also have a tapetum lucidum, a layer of tissue that reflects light, at the back of their eyes. This reflection provides more light to the retina than an animal without this specialized tissue would have in the same setting. The tapetum is most obvious when your cat’s eyes are dilated, and you can see the “glow” reflected when you shine a flashlight toward your cat.
Vision Range
Cats have a wider peripheral field of vision than people. Their range is about 200 degrees versus 180 degrees in a person, which helps the cat hunt. Cats are better at detecting motion, even in low light, which helps them spot prey.
Many of the prey that cats hunt is active from dusk to dawn, so cats have evolved to hunt during conditions of dim light. Of course, cats also use their other highly developed senses of hearing, smell, and touch to hunt.
As you can see, although your cat doesn’t have night-vision goggles, she does have natural adaptations that help her see in low light.
