Screech Owl Owl

So extraordinary is an owl's night vision, it can spot a mouse creeping through the underbrush more than a football field away on a moonless night. A number of factors are responsible: an unusual eye shape that provides a broad retinal surface; an iris that can dilate almost twice as wide as a hawk's iris; and a special lens that enlarges visual information much like a telescope does.

What's different about the nocturnal eye?

Photo: Corbis-Bettmann.

Night Vision | Zoology After Dark
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