"The State of the Birds" 2014 report found that red knots (above) and other shorebirds are among the most threatened groups in the U.S. More than half of U.S. shorebird species are on the report's Watch List — species that are currently endangered or at risk.
Gerrit Vyn/The Smithsonian Institution
The granulated surface of the lake bed known as the Racetrack is a favorite destination for tourists — and for scientists who want to investigate trails left by the meandering stones.
Momatiuk - Eastcott/Corbis
Being a bit coldblooded has its charms, scientists say. A mammal the size of a T. rex, for example, would have to eat constantly to feed its supercharged metabolism — and would probably starve.