A domestic cat’s eye narrows to a razor-thin vertical slit in bright sunlight, while a grazing sheep stares out through a ...

Across land, sea, and air, they use a mix of stealth, mimicry, and lightning-fast attacks to feed, and in some cases, defend themselves.

While both cats and snakes have slit-like pupils, the similarity ends there. It’s a case of convergent evolution--understand ...

Pupil shapes vary widely across the animal kingdom, from the W-shaped pupils of cuttlefish to the bar-like pupils of goats.