If you’ve ever wondered why cat’s eyes look so cool, check out this explanation that covers both predator and prey:
We found animals with vertically elongated pupils are very likely to be ambush predators which hide until they strike their prey from relatively close distance. They also tend to have eyes on the front of their heads. […]
In contrast, horizontally elongated pupils are nearly always found in grazing animals, which have eyes on the sides of their head. They are also very likely to be prey animals such as sheep and goats.
Why is this? Essentially, modeling shows that vertically elongated pupils allow a predator the ability to judge distances without moving its head, thus giving prey fewer opportunities to notice its approach. At the same time, prey with elongated horizontal pupils and eyes on the sides of their head are able to see nearly the entire area around their bodies, providing them with a keen early warning system against predators.
Pretty neat stuff — definitely worth reading about!