With a diversity in wildlife rivaled only by watering holes in the Serengeti, the bicyclist or tram-rider on the fifteen-mile Shark Valley loop is almost guaranteed a stellar showing of Everglades fauna: Roseate spoonbills, wood storks, and great blue herons delicately pick their way through shallow pools and pose serenely in branches. Spotted gar, red-belly turtles, and anhingas swim beneath the water's amber surface. Cormorants decorate the tram road's watchtower like gargoyles, and short-tail hawks soar overhead. The king of this jungle, however, is the American alligator, Alligator mississippiensis, whose green-gray bulk is draped over every muddy bank and drainage pipe that can offer him some sunshine. Beware of this dweller of murky puddles: He may seemingly ignore the fluttering and prancing of the wildlife around him, honed by millennia of evolutionary adaptation to expend as little energy as possible (he navigates canals swimming, propelled by the merest flick of the tail) but the gator is no slow fuddy-duddy of a predator. "Never get closer than fifteen feet to an alligator," warn signs and brochures. "If it hisses or opens its mouth in defense, you should back away even farther." A nice reminder, rendered totally unnecessary at the first glimpse of sharp, crooked teeth. Bike rental is $6 an hour; tickets for the tram are $14 for adults and $8 for children.