Scientists explain why cats’ eyes glow in the dark. The tapetum lucidum reflects light, enhancing night vision. Similar structures are found in cows, horses, and marine animals.
Scientists have explained why cats’ eyes glow in the dark — and the reason lies in a special reflective layer inside their eyes.
According to Popular Science, behind a cat’s retina is a mirror-like layer called the tapetum lucidum, which reflects light. This reflection is what causes cats’ eyes to glow in low-light conditions.
In ancient Egypt, people believed that cats’ eyes captured sunlight after sunset, which made them glow at night. However, the real scientific explanation was discovered in 1929. Only later did researchers fully understand how this unique structure improves feline vision.
The retina is a thin layer at the back of the eye that absorbs light and converts it into signals sent to the brain. In cats, light that passes through the retina without being absorbed reaches the tapetum lucidum. This reflective layer sends the light back through the retina, giving it a second chance to detect the light. The visible “glow” at night is simply light bouncing off this reflective surface.
Thanks to this adaptation, cats have much greater light sensitivity than humans. They can see in lighting conditions that appear almost completely dark to us — an essential ability for animals that hunt at night.
Cats are not the only animals with this reflective layer. Cows, sheep, goats, and horses have a similar eye structure, which helps them detect predators in dim light. Marine animals such as fish, dolphins, and whales also possess this feature, enabling them to navigate in dark underwater environments. In contrast, squirrels, pigs, most primates, and humans lack the tapetum lucidum because they are primarily active during the day and do not rely on night vision.
The structure of cats’ eyes has also inspired modern technology. For example, Dr. Young-min Sohn from the Korea Advanced Institute of Science and Technology developed a camera inspired by feline vision.
He explained that he has long been fascinated by animals’ ability to see in a wide range of lighting conditions. His camera design includes a reflective layer that improves image quality in low-light environments without increasing power consumption. Later, he added a slit-shaped aperture inspired by the vertically elongated pupils of cats.
According to Dr. Sohn, similar principles could be applied beyond cameras — including robotic vision systems, autonomous technologies, wearable devices, and surveillance systems that must function reliably in both bright and low-light environments.
In a separate interview with Izvestia on February 13, clinical psychologist Maria Tsareva from the Leleya School of Women’s Psychology commented on the psychological effects of cats. She stated that there is not enough scientific research to confirm a definite positive impact of cats on humans. However, she noted that interacting with a pet in the morning may gradually increase dopamine levels in both men and women.
