In the Everglades, everything still looks the same. The waving saw grass, the cypress and pine trees draped with air plants, the high, white clouds parked like dirigibles above their shadows—if you’ve been to the Everglades before, and you go back, you’ll still find these. But now there is also a weird quiet. In the campsites of Everglades National Park, raccoons don’t rattle the trash can lids at four in the morning. Marsh rabbits don’t scatter with a nervous rustle on the hiking trails as you walk by. Tires don’t shriek when somebody brakes to avoid an opossum transfixed by headlights in the middle of the road. In fact, roadkill, which used to be common in this wildest part of Florida, is no longer seen. The raccoons and marsh rabbits and opossums and other small, warmblooded animals are gone, or almost gone, because Burmese pythons seem to have eaten them. The marsh’s weird outdoor quiet is the deep, endlessly patient, laser-focused quiet of these invasive predators. About two feet long when hatched, Burmese pythons can grow to 20 feet and 200 pounds; they are among the largest snakes in the world. The pythons are mostly ambush hunters, and constrictors. They kill smaller ani...