Eyes Of Animals: More Than Just Exotic Beauty

Animals have been observed by man since the dawn of mankind, when men threw the spears and women harvested the wild veggies. But one thing not too often observed in animals is their eyes. Their pretty, exotic little eyes are certainly nice to look at, assuming you’re not being eyed by a hungry panther. But unlike human eyes, which usually differ only in iris color and ability to see, animal eyes vary wildly in all aspects.

Pick up your kitty cat and you can clearly see she’s got vertical slits for pupils. Why is this? Because your sweet little Fluffy is an ambush predator, and one that’s close to the ground at that. Cats are the kind of animals that patiently lay in wait for unsuspecting birds or rats to pass by so they can leap out and feast. But to do that, Fluffy needs to accurately judge the distance between herself and her food, and a vertical slit pupil is ideal for such a thing – but only if Fluffy is housecat-size. If Fluffy is in fact a tiger or a lioness, she’ll likely have round pupils, which are better suited for taller predators that chase their prey down (Benny Hill theme optional).

On the other hand, if the animal IS the prey, they generally have horizontal slits for pupils, and eyes on each side of their head. This gives animals such as horses and sheep an advantage, as they have a panoramic view with which to scan all directions for threats. And since horses and sheep spend a lot of time grazing, with their heads facing the Earth, they have evolved the ability to roll their eyes very far upward so that their line of sight is parallel to the ground and horizon.

This isn’t just something scientists think about. Pick up any fantasy novel or sci-fi movie and you’re likely to find a character with strangely-shaped pupils, either to convey otherworldliness or malevolence. While creepy, characters like Lord Voldemort or the Indominus Rex in Jurassic World possess unrealistic eyes, as the former is a humanoid abomination, and the latter is a HUGE DINOSAUR, and therefore both are far enough off the ground to warrant having round pupils.

Less studied than the above, but no less fascinating, are reptiles and marine life. Cuttlefish have pupils shaped like a “W.” Dolphins have fancy little crescent-shaped pupils like moons. Geckos have pinhole pupils, and cutest of all, some frogs have heart shaped pupils. So the moral of the story today, kids, is that if you love someone, train one of those frogs to carry presents to them, because that’s adorable. Just… make sure they’re not afraid of frogs.

Greenfieldboyce, Nell. “Eye Shapes Of The Animal World Hint At Differences In Our Lifestyles.” NPR. NPR, 7 Aug. 2015. Web. 13 Aug. 2015.