A pinprick of movement. Across open air, an eagle can lock onto detail because its retina packs light-sensing cells into a tight photoreceptor mosaic rather than relying on an oversized eyeball alone. The result is not magic. It is retinal sampling pushed hard, turning tiny contrasts into usable signals before they disappear in distance and glare.Size is the decoy. Within the retinal fovea, cones ...More