Scientists from the University of California, Berkeley and Durham, Britain have stated that vertical and horizontal pupils in animals are part of their survival process. A study published in the journal Science Advances reports that vertical and circular pupils help certain predators to hunt whereas horizontal pupils help preys to save their lives.
For the study, researchers studied 214 species and used computer models based on a sheep’s eye to establish how horizontal, vertical and circular pupil helps animals. According to the theory, animals with horizontal pupil could capture more light from the left and right side of the eye. They however could capture less light from below and above the eye. With horizontal eyes, it will be easier for grazing animals such as sheep and goat to detect their predators from afar.
One would argue what would happen when the animal is grazing? Its eyes would be perpendicular to the ground. But scientists here made a starking revelation by asserting that eyes of goats rotate as much as 50 degrees in either direction when their head is down. The study used all terrestrial vertebrates which included Australian snakes, every species from the cat and dog families, hyenas, mongoose and domestic grazing animals including tapirs and rhinoceroses. It presents a unique case of evolution over millions of years.