Every year, the Arctic tern (a bird weighing less than five ounces) completes one of the greatest journeys in the animal kingdom.  In their constant search for daylight, moderate temperatures and small fish on which to feed, the terns literally follow the sun from the North Pole to Antarctica, and back again.  Their migrations can extend more than 50,000 miles, and the biological systems that make this odyssey possible offer spectacular displays of intelligent design and purpose in the living world.

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