Sagebrush rustled as 400-lb. prehistoric beasts rose up on strong legs and thundered past us into a steaming pond. After the dust settled, eerie reptilian heads rose through the translucent water until only jewel-like eyes and domed snouts poked above the surface. The high-desert country of the Snake River Plain is a far cry from the lush subtropical swamps of the U.S. Gulf Coast, but a with a perfect combination of sparkling geothermal water and abundant food from local fish farms, captive American alligators thrive in the harsh climate of southern Idaho