Irish legend has it that “a cat’s eyes are windows enabling us to see into another world”. Cat eyes are truly mesmerizing, but have you ever wondered why cats have vertical pupils?
A study published in the journal Science Advances explains that animal pupils are linked to their ecological niche. Ambush predators such as cats, foxes and snakes have vertical pupils that allow them to better judge the distance between them and their prey without having to move their head, which could give away their location. In contrast, grazing animals such as goats have horizontal pupils on the sides of their heads that allow them to detect predators as early as possible. Active foragers, like humans and dogs, tend to have front-facing eyes with round
Cats are crepuscular, which means they do most of their hunting at sunset and sunrise (when mice are scurrying around!). Because of this, their eyes are equipped to see very well in dim light, but they are also extremely sensitive to bright light. Vertical pupils allow for greater and more accurate control of how much light enters a cat’s eyes. Cats can further control how much light enters their eyes by bringing their eyelids closer together.