GOLDEN EAGLE: No animal on earth boasts better vision than this bird of prey. A golden eagle can spot a hare from a mile away and keep it in sharp focus until it strikes. Its field of vision is wider than any other animal's and up to eight times sharper than our own. One reason for the eagle's excellent sight is the size of its eyes, which are gigantic in proportion to its skull. Large eyes let in more light for better vision. They also allow for a larger retina — a membrane at the back of the eye that translates light into signals that the brain can interpret. The eagle's retina is coated with four to five times as many light-sensitive cells per square millimeter as ours, allowing for much greater resolution. And where we have one fovea — the most visually receptive part of the retina — the eagle has two, allowing for a much wider field of vision. Its ability to quickly focus on objects, and remain focused from a mile to less than one foot away, far exceeds ours. The eagle has binocular vision like we do, but the view from its left and right eye overlap to a greater extent than ours. This gives it a greater sense of depth and three-dimensionality than we have.