Why do cats have vertical pupils?
Short answer
A cat’s vertical pupils can control the amount of light entering the eye over a wide range. Research also links vertical pupils with ambush predators that judge distances close to the ground.
How it works
The pupil is the opening that lets light into the eye. In bright light, a cat’s iris can narrow the pupil into a thin vertical slit. In dim light, the pupil expands to collect as much light as possible.
Research has found that vertical pupils are common among low-to-the-ground ambush predators. The shape may help keep vertical contours sharp and use blur as another clue for estimating distance before a pounce.
Key point
Pupil shape does not explain an animal’s whole way of life by itself. Eye position, body size, and activity time matter too. A vertical pupil is one visual feature that fits the way many cats live and hunt.