Burmese pythons have caused a severe decline in native wildlife across the Florida Everglades, with recent data showing that mammal populations in the southern region have dropped dramatically. Raccoon numbers have fallen by more than 99 percent, opossums by nearly 99 percent, and marsh rabbits have disappeared from areas where they were once common. Bobcats have declined by approximately 87 percent.

Researchers have attributed this collapse to the python invasion, which began in the 1990s when pet owners released unwanted snakes into the wild. The Everglades closely resembles the python’s native habitat in Southeast Asia, and Florida wildlife had no natural defenses against the large constrictor. A single female python can lay up to 100 eggs per year, allowing the population to grow to an estimated 300,000 snakes within two decades.

Trail cameras placed throughout the swamp show that surviving animals have changed their behavior significantly. Raccoons remain in their dens for days at a time rather than foraging, and rabbits have stopped breeding. The presence of pythons has created such intense stress that some prey species are effectively shutting down their normal patterns, even when they are not directly attacked.

Beyond the direct impact of the pythons themselves, researchers have identified a secondary threat. Native snake species, including pygmy rattlesnakes, corn snakes, and garter snakes, have been found dead with no obvious cause. Laboratory examinations revealed that their lungs were filled with parasitic worms. The parasite, an Asian snake lungworm, evolved alongside Burmese pythons and does not harm them. However, it is lethal to Florida’s native snakes, which have no immunity to it.

The lungworm spreads through a chain that does not require the pythons to remain present. Python waste contains microscopic eggs, which are consumed by insects. Frogs eat the insects, and native snakes eat the frogs. Once infected, the worms travel through the snake’s body to the lungs, where they block the airways, leading to suffocation over a period of weeks or months. The parasite has now established itself independently in the native food web, meaning its spread would continue even if every python were removed from the swamp.

Infected snakes have been found as far north as Jacksonville. Internal reports suggest that several native snake species face regional extinction within the next two decades because of the parasite. The cottonmouth water moccasin appears to handle the infection better than other species, though the reason is not yet understood.

Efforts to control the python population have included bounty programs, professional hunters, and tracking studies, but these measures have not kept pace with the snakes’ reproduction rate.

In response to the crisis, a coalition of zoos and wildlife agencies has been working to restore populations of the eastern indigo snake, the longest native snake in North America. The indigo feeds primarily on other snakes and is immune to the venom of American pit vipers. The species had been wiped out from northern Florida decades ago due to habitat loss and road mortality. A captive breeding program has now released indigo snakes in the Apalachicola region, and recent trail camera footage confirms that they are breeding in the wild. Because indigo snakes actively hunt other snakes, including juvenile pythons, they may serve as a natural check on python expansion along the northern front.

There are also signs that native predators are adapting to the presence of pythons. Trail cameras have recorded a bobcat destroying a python nest and eating the eggs. Other footage shows bobcats hunting and killing juvenile pythons and caching the carcasses for later consumption. Alligators have been observed ambushing young pythons near the water’s edge. Researchers describe this as biotic resistance, a process in which native ecosystems gradually adapt to an invasive species, though it typically takes decades to develop and sometimes never occurs at all.

The situation in the Everglades remains unresolved. The python population continues to push northward, limited in part by cold winter temperatures. The parasite they carry is spreading faster than the snakes themselves. At the same time, native predators are beginning to respond, and reintroduced species like the indigo snake are reestablishing themselves. Researchers monitoring the region describe the outcome as uncertain, with the next phase of the story still being written in the swamp.