How Burmese Pythons Invaded Florida With 100,000 Now Roaming the Everglades

Burmese pythons have become a hugely successful invasive species in southern Florida over the past few decades. But how did these huge snakes establish themselves in this part of the United States?

Burmese pythons, as the name suggests, are native to Southeast Asia. However, there are now a large number of these snakes, which can grow to lengths of 20 feet and weigh more than 250 pounds, living in the south of the Sunshine State.

The exact size of the Florida Burmese python population is not known because the snakes are very hard to detect, but estimates range from the tens of thousands, to more than 100,000, or perhaps even upwards of 300,000.

How Did Burmese Pythons Become Established in Florida?

A Burmese python in Florida
A Florida Fish and Wildlife Conservation official holds a Burmese python on March 23, 2021 in Fort Lauderdale, Florida. Burmese pythons are considered to be an invasive species in the state. Joe Raedle/Getty Images)

Burmese pythons, which are one of the largest snakes in the world, were introduced to Florida in the 1970s and 1980s when thousands of the snakes were imported to be sold as exotic pets.

But some owners who were unable to handle the giant snakes and find new homes for them released them illegally into the wild. Other pet Burmese pythons also managed to escape on their own. These newly freed pet snakes then began to breed in the wild, eventually establishing a population in the state.

Research indicates that the most likely course of establishment for this species was the release of a small number specimens prior to the mid-1980s.

"Because pythons are so well camouflaged and hard to find, the population went mostly unnoticed until the late 1990s and early 2000s," Bryan Falk, a program analyst at the National Invasive Species Council, told Newsweek.

"Pythons have cryptic coloration and can hide well, and even expert searchers may find only 1 percent of the pythons that are in the area they are searching," he said.

The species is now considered to be invasive in the state, where they are distributed across more than 1,000 square miles of the south, primarily in the Everglades ecosystem but also some areas to the north, according to the U.S. Geological Survey.

Why Have Burmese Pythons Been so Successful in Florida?

Burmese pythons are not constrained by natural factors as much as they were in their native range, while Florida's favorable subtropical climate and the vast, undisturbed ecosystem of the Everglades have provided the perfect conditions for them to thrive, according to a study led by Frank Mazzotti from the University of Florida. Other factors have also helped the pythons.

"Pythons' rapid and widespread invasion is facilitated by aspects of their natural history such as diverse habitat use, broad dietary preferences, long lifespan (15-25 years), high reproductive output, and ability to move long distances," the authors of the study wrote.

"Burmese python hatchlings are larger than hatchlings of native species and are less susceptible to predators. These multiple advantages may allow pythons to compete with native snakes and other predators for food, habitat, and space."

In addition, Burmese pythons are excellent swimmers and can travel long distances in water, making them ideally suited for the environment of the Everglades.

What Damage Are Burmese Pythons Doing to Local Ecosystems?

Burmese pythons are considered to be one of the most concerning invasive species in southern Florida due to the significant impact they are having on native wildlife.

These snakes eat more than 70 species of mammals and birds in the state, and they even occasionally eat alligators.

"Some native prey populations have significantly declined because of pythons, and we are just beginning to understand the cascading effects of these and other, less obvious impacts to the Florida ecosystem," Falk said. "One example is disease transmission."

"Because pythons have reduced the number of mammal species, mammal-feeding mosquitoes are now feeding more often on rodents, and rodents are hosts to Everglades virus, which the mosquito can then transmit to humans," he said. "The implication is that in areas where pythons occur, a person may be more likely to become sick from a mosquito-borne mammal virus, which underscores the complexity of impacts that invasive species can have."