"Preeeeep." The sound of the peepers, tiny frogs an inch or two long, penetrated the dusk. Beneath the jack pines at the edge of a small pond in the northern Michigan woods, the males were calling their mates. A professor and a group of ecology students sat speechless as closer and closer, louder and louder, more and more peepers joined in chorus. There was just light enough to see them, crawling up a bracken fern to find a singing perch, filling their throats with air like tiny balloons about to burst and then giving forth at close range an ear-splitting 'preeeeep.; . . . Now we were...