It is said that eyes are the window to the soul, and these incredible beasts certainly must have some beautiful souls if their eyes are anything to go by! Eyes come in several different shapes, and in nature the pupil shape can also differ. It is believed that vertical pupils are found in ambush predators, horizontal pupils belong to grazers, and the “w-shaped” pupil, belonging to creatures such as the cuttlefish, remains as yet unexplained! AMAZING!
source: The Conversation