The Invasive Species That's Destroying The Florida Everglades

Invasive species are causing major problems across the United States. From the wild pigs that dominate Texas to the Golden Mussels plaguing California, the U.S. currently hosts more than 6,500 invasive species. These invaders can have devastating impacts on their adopted environments. Invasive species can endanger other organisms and damage ecosystems, causing economic damage in the process, and South Florida is a prime example of an environment being quietly destroyed by an invasive species: the Burmese python.

Native to India, China, the Malay Peninsula, and some East Indies islands, the Burmese python has become a major problem in South Florida since the 1990s when the reptiles were brought into the state in record numbers to be sold as pets. Reports state that an estimated 99,000 pythons entered Florida from 1996 to 2006.

Today, estimates say that the Burmese python is present in more than a thousand square miles of southern Florida, reaching from coast to coast. From the Everglades National Park, to Rookery Bay National Estuarine Research Reserve, all the way to southern Miami, Burmese pythons have become an increasingly prevalent threat.

Burmese pythons are some of the largest snakes in the world, reaching up to 23 feet in length and weighing up to 200 pounds. Tan in color, with dark patches that mimic the look of a giraffe's skin, Burmese pythons are semi-aquatic, and they are capable of staying submerged in water for up to 30 minutes.  Though their early life is spent mostly in trees, as they grow in size, the pythons will transition to the ground where they stalk their prey using chemical receptors in their tongues and temperature-sensitive mechanisms along their jaws. This allows the creatures to sense nearby animals even in the dark — making up for their poor eyesight. 

The python is a nonvenomous constrictor, which means that once it sinks its teeth into prey, it then coils around the animal and squeezes it to death. As if that wasn't terrifying enough, Burmese pythons also have stretchy skin between their lower jaws that allows them to devour prey equivalent to 100% of their body mass and up to six times larger than other snakes their size, making for some truly nightmarish images of pythons consuming deer and other large animals. 

According to reports, adult Burmese pythons caught in Florida average between 6 and 9 feet, though the largest ever caught in the state measured more than 18 feet long.

Burmese pythons are not native to Florida. Instead, they were brought into the state during the 1990s when they became a desirable pet. Some of the snakes escaped into the wild, some were intentionally released, and all immediately thrived amid an environment especially conducive to their survival. Put simply, Southern Florida provided plentiful prey for the pythons, which feasted on mice, squirrels, birds, and even the state's larger animal population — as was the case in 2022 when Florida scientist Rosie Moore posted a video on Instagram (via The Palm Beach Post) showing how they discovered the remains of an entire alligator inside an 18-foot Burmese python. Part of the problem is the snakes' large size, which means they have very few predators to worry about.

Unsurprisingly, then, the U.S. Geological Survey (USGS) calls Burmese pythons "one of the most concerning invasive species in the area." What is surprising, however, is that it took until April 29, 2021, for the pythons to be added to Florida's Prohibited species list, which means that only specific entities are allowed to possess the creatures for the purposes of research, educational exhibition, and control or eradication. Meanwhile, back in 2012, the United States Fish and Wildlife Service (USFWS) listed Burmese pythons as an Injurious Species under the Lacey Act, essentially banning the import of any more of these snakes into the country.

Today, it's not known how many Burmese pythons live in the wild in Southern Florida. The constrictors can survive in multiple habitats and often occupy areas that are difficult to access, making it hard to conduct surveys on their population numbers. Still, the agency estimates that tens of thousands of Burmese pythons currently occupy the Greater Everglades region.

Typically, when an invader takes over a new environment, existing animals become endangered due to that invasive species. In the case of Florida and its Burmese python problem, the snakes are ravaging the local wildlife populations with their insatiable appetite. Everything from alligators to birds and even pets such as cats and dogs have been found inside the stomachs of the dangerous snakes. Endangered species aren't safe either. The Federally designated Threatened wood stork and the Federally designated Endangered Key Largo woodrat are two examples of endangered animals that have been eaten by Burmese pythons.

The result of all this is an ecosystem devastated by an out-of-control Burmese python population. In 2012, a study in Proceedings of the National Academy of Sciences found that, between 2003 and 2011, there had been a 99.3% decrease in the frequency of raccoon observations, a 98.9% decrease in opossum sightings, and a 87.5% decrease in bobcat observations. What's more, rabbit sightings stopped completely, with the USGS confirming that marsh rabbits and foxes were essentially wiped out during the same period. Researchers noted that these species are more common in areas where pythons had only recently been discovered, and are most common in areas without pythons, suggesting it was the presence of the snakes that had caused such dramatic declines.

Mike Kirkland, senior invasive animal biologist at South Florida's water management district, told the BBC, "[The snakes] have devastated our ecosystem," and he further claimed that following the introduction of Burmese pythons to the Everglades National Park, the population of furry mammals has been nearly wiped out.

In 2024, the BBC reported on what is surely the most Florida solution to the issue of an invasive species. Back in 2017, the state had begun paying bounty hunters to control the python population. These hunters — comprising 50 paid contractors across nine counties — track down pythons and kill them using bolt guns. As of March 2024, the project had resulted in 8,565 pythons being killed across the state. But killing the invasive snakes is only part of the solution to what is a wide-ranging problem.

The issue is bigger than the fact Burmese pythons eat local wildlife. A 2017 study in the Journal of Applied Ecology also found that there were significant "trophic cascades" that stemmed from the introduction of Burmese pythons into Florida. The researchers made artificial turtle nests and watched the process of predation at each, noting that in areas where pythons were well-established, predation was extremely low, suggesting animals were altering their natural habits due to the presence of the snakes. In other words, the study suggested that Burmese python populations were responsible for strong indirect effects on the Everglades' ecosystems, and called for an urgent management of the species.

In that sense, snake bounty hunters are the very least Florida can do to deal with what is clearly a giant threat to its ecosystems.