Since the giant constrictors took hold in Florida in 2000, many previously common mammals have plummeted in number—and some, such as cottontail rabbits, may be totally gone from some areas.

Scientists already knew from dissecting the snakes that they prey on a wide range of species within Everglades National Park. (See a picture of a Burmese python that exploded eating an American alligator in the Everglades.)

Also popular as pets, Burmese pythons are one of nine species of constrictor snakes, numbering about a million individuals, that have been imported into the United States over the past three decades, according to the U.S. Fish and Wildlife Service. Many of these animals, which can grow to lengths of 20 feet (6