A human eye weighs less than 1 percent of the weight of the head. Owl eyes are so large that there is little room in their skulls for eye muscles. Thus, an owl turns its head, sometimes as much as 270 degrees, rather than its eyes, to follow a moving object. It has been said that the difference between the hunter and the hunted is evident in the eyes. The hunted have eyes on the sides of their heads to obtain a wide field of view.
Hunters have eyes on the front of their heads to increase depth perception.
Owls have the most frontally positioned eyes of any animal. Contrary to popular belief, owls have excellent vision in both daylight and at night. Their pupils are huge at night, letting in great quantities of light. Meanwhile, in the daytime, they shrink to the size of a pinpoint. But it is at the expense of color defining cones, so,while owls see well in dim light, they see little color.