Why do pupils come in so many different shapes? A new study suggests it all has to do with the animal’s size and whether they are predator or prey.
For example, longer pupils are found in predators that lie in wait for their prey, like small cats. These predators need to accurately judge the distance to their prey, and the vertical slit has optical features that make it ideal for that.
But that rule only holds if the animal is short, so its eyes aren’t too high off the ground. Larger cats like lions (who chase down their prey) tend to have round pupils.
Lion by sarit, Nigerian dwarf goat by Yoopery, Gargoyle gecko by v1ctory_1s_m1ne, Kitten by Kévin V. Pxl, Cuttlefish by Alexander Vasenin, Horse by Michael Wifall, Fantail stingray by Philippe Guillaume