Florida officials have spent years and millions of dollars trying to control the state’s Burmese python population, a species that has spread widely through the Everglades since being introduced through the exotic pet trade. At a recent event in Stuart, Governor Ron DeSantis discussed new actions the state plans to take in that effort.

The population has proven difficult to manage through conventional hunting. Since 2017, state agencies and licensed hunters have removed more than 10,000 pythons from the Everglades. Despite this, the population continues to grow. By some estimates, it takes an average of 12 combined agency hours to remove a single python. A single female can lay up to 100 eggs per clutch, and reproduction is believed to be outpacing removal efforts.

One proposed method has drawn particular attention: aerial distribution of acetaminophen-laced baits, a technique tested successfully in Guam. The compound is lethal to snakes because their livers lack the enzyme that allows humans and other mammals to metabolize it safely. A dose of roughly 80 milligrams is enough to kill a snake of moderate size.

The approach has never been used in Florida, and a single mouse has not yet been dropped over the Everglades. But the research behind it has changed how scientists think about python control, even as it has raised serious concerns about risks to native wildlife.

The Guam precedent

The method was developed after decades of difficulty managing an invasive species on the Pacific island of Guam. A brown tree snake arrived there in 1952, likely in a military cargo shipment. With no natural predators and an abundant supply of prey, the population expanded rapidly. By the 1980s, researchers estimated as many as 5,000 brown tree snakes per square mile in some areas of the island. Several bird species stopped breeding in the forests, and the island’s bird population collapsed.

In the 2000s, the U.S. Department of Agriculture tested a delivery method using dead mice injected with acetaminophen. The baits were attached to cardboard streamers and dropped from helicopters. In test areas, surveys found snake declines of about 80 percent.

Laboratory research confirmed that Burmese pythons share the same vulnerability to acetaminophen as brown tree snakes. Juvenile pythons, which are similar in size to an adult brown tree snake and hunt small rodents, readily consumed baits carrying the same 80-milligram dose.

The logic of targeting juveniles is straightforward. Adult pythons are too large to be affected by a baited mouse, but young pythons are the natural targets. If enough juveniles are removed across a sustained period, the adult population would eventually stop being replenished.

The risks to native wildlife

The Everglades, however, is not Guam. By the time baits were used on Guam, the island had already lost much of its bird population, making the collateral risks easier to manage. South Florida supports roughly 350 bird species, 60 reptile species, 40 mammal species, and 50 fish species. Acetaminophen is not selective, and the delivery method presents risks to several groups of animals.

Raccoons and opossums, both of which have declined sharply due to python predation, feed on rodents and could consume the baits. Secondary poisoning is another concern. If a small animal eats a sublethal dose and survives, residue can remain in its tissue, and predators that eat it later may be affected. Young raptors, including bald eagles, ospreys, and red-tailed hawks, are considered more vulnerable to this kind of exposure than adults.

The Florida panther is a particular concern. The wild population is estimated at between 120 and 230 animals, concentrated in the southwestern part of the state. Panters are scavengers as well as hunters, and a dead mouse left on a low branch would be an easy food source. Cats lack the same enzyme that protects humans from acetaminophen, and even small doses can be fatal to them. Panther habitat and python habitat overlap heavily, and the loss of even a few panthers could have lasting effects on a population already under pressure.

Another animal of concern is the eastern indigo snake, the longest native snake in North America. It is one of the few animals that will actively hunt juvenile pythons and is considered a natural check on python numbers. Its own population has declined for decades, and it is now supported through captive breeding programs. Indigo snakes eat mice, but whether they have any tolerance for acetaminophen is unknown. The species that could naturally help control pythons may be vulnerable to the same bait.

Water is also a factor. Python habitat is defined by water, so baits would need to be concentrated near marshes. A share of the baits would likely land in water, where fish could consume them. The compound could then enter aquatic food chains in ways that would be difficult to monitor.

Lessons from Australia

Australia has already seen what can go wrong with this kind of large-scale approach. Invasive foxes, cats, and rabbits were managed there using a compound lethal to those species but far less toxic to native animals that had evolved alongside it. Initially, the program appeared successful, and native marsupial populations rebounded in some areas. Over time, however, eagles died from consuming poisoned carcasses, the compound moved through food chains in ways the models had not predicted, and some rabbit populations developed measurable tolerance to the poison.

The Australian campaign was carefully monitored and driven by legitimate conservation intent, but it still produced unintended consequences. The experience illustrates a broader point: releasing a lethal agent into a complex ecosystem does not operate along the lines of a management plan.

Where things stand

Until a viable alternative is found, the removal efforts continue. Thousands of pythons are still pulled from the Everglades each year. Radio tracking a captured female to a breeding aggregation has become one of the more effective methods. Other possible approaches, including pheromone traps, pathogen-based controls, and genetic techniques, are under study but are not yet ready for use.

The acetaminophen method has not been deployed in Florida, and it may never be. What the research has done is clarify a difficult tradeoff: a proven tool exists for reducing python numbers, but the ecological risks in the Everglades are serious. The very diversity that makes the region worth protecting also makes this particular method difficult to use there.

The pythons remain. Their population continues to grow, and no method currently available has been able to reverse the trend.