" Human eyes are set in the front of our heads. This gives us binocular, stereoscopic vision, which means that our eyes combine the images we see to obtain a three-dimensional effect. This results in excellent depth perception, also shared by other hunters, such as dogs, cats, hawks, and owls. Horses, however, have eyes set on the sides of their heads, providing excellent lateral vision, a trait they share with other prey species, such as sheep, deer, rabbits, ducks, and pigeons. "

― , Why Do Horses Sleep Standing Up?: 101 of the Most Perplexing Questions Answered about Equine Enigmas, Medical Mysteries, and Befuddling Behaviors