U.S. National Park Service biologist Skip Snow examines a 10-foot, 3-inch (3.1-meter) Burmese python captured on an access road to Florida's Everglades National Park last fall. Experts say the snakes—the species is one of the world's largest and a favorite of the pet trade—are released in the area by disenchanted pet owners. Since the mid-1990s, park rangers have captured or killed 68 Burmese pythons in Everglades National Park.