Page 110 - Miracle in the Eye
P. 110
MIRACLE IN THE EYE
other species. Looking for food, these predator birds search for small animals
on the ground, and their eyes can pick up the slightest movements, thanks to
a high number of light-sensitive rods in their retinas. As we explained, the
more rod cells, the keener night vision becomes. But for this vision, predator
birds do pay a price: They sacrifice the sense of color. They see the world in
black and white but, owing to their lifestyle, they do not need to see color. So
cone cells are quite fewer in the eyes of nocturnal birds.
During the past minute, as you read this book, you blinked 22 times.
That's how your eyes maintained their moisture and cleanliness. But for that
split-second that you blinked, your eyes stopped doing their job. For the rela-
tively sedate lifestyle of a human, this may not be a problem. But for a bird in
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