The core question of whether anacondas are established in the Everglades can be answered definitively: they are not. However, the presence of large, invasive constrictor snakes is a serious reality in the South Florida ecosystem, which often leads to this confusion. Individual anacondas, primarily the Green and Yellow species, have been sighted and captured in the region, but these are almost universally attributed to escaped or illegally released pets. Concern over massive non-native snakes is justified, as one particular invasive predator is causing immense ecological damage.
Are Anacondas Established in the Everglades?
Occasional sightings of both the Green Anaconda, Eunectes murinus, and the Yellow Anaconda, Eunectes notaeus, have been documented in the Everglades, but they do not represent an established, breeding population. These isolated finds are typically single individuals that have either escaped or been intentionally released into the wild. The first confirmed anaconda sighting occurred in 2003, and while more have followed, they remain rare occurrences.
While the warm, aquatic environment of the Everglades appears superficially similar to the anaconda’s native South American habitat, it may not be suitable for long-term survival and reproduction. Winter temperatures in South Florida can occasionally drop low enough to cause mortality in tropical species like the anaconda, preventing them from establishing a large population. The lack of verifiable evidence of reproductive activity suggests that these snakes are not yet a permanent fixture of the ecosystem.
The Dominant Invasive Constrictor
The invasive snake that has successfully colonized and is thriving in the Everglades is the Burmese Python, Python bivittatus, which is often the source of the public’s confusion about large constrictors. This species was introduced to Florida through the exotic pet trade, with thousands imported into the U.S. between 1996 and 2006. The population became officially recognized as self-sustaining and reproducing in the wild around the year 2000. Some researchers suggest Hurricane Andrew in 1992 contributed to the initial releases from damaged facilities.
The Burmese Python’s physical characteristics contribute to the misidentification, as they are one of the world’s largest snakes. Adults in Florida average between 6 to 9 feet long, and the largest captured specimen exceeded 18 feet in length. Their tan coloration with dark, irregular blotches makes them distinct, but their massive size often leads to them being incorrectly labeled as an anaconda. This highly successful invasive predator is now established across a vast area of South Florida. While exact population figures are difficult to obtain due to their elusive nature, estimates range widely, from tens of thousands to as high as 300,000 snakes.
Ecological Disruption by Large Invasive Snakes
The established Burmese Python population has caused severe disruption to the native Everglades ecosystem, primarily through predation. These apex predators consume a wide variety of native wildlife, including birds, mammals, and even alligators. Gut analyses show they target endangered species like the Key Largo woodrat. The most profound consequence has been the near-total collapse of mammal populations in the remote core areas of Everglades National Park where pythons have been established longest.
Research indicates a staggering decline in mammal sightings coinciding with the python’s proliferation. Since 1997, raccoons have decreased by 99.3%, opossums by 98.9%, and bobcats by 87.5%. Smaller mammals such as marsh rabbits, cottontail rabbits, and foxes have effectively disappeared from core areas of the park. The pythons’ large size offers them protection, as they quickly grow beyond the size where native predators like alligators pose a threat, allowing their population to expand unchecked.
Current Control and Management Strategies
Efforts to control the Burmese Python population involve a coordinated strategy between state and federal agencies, focusing primarily on removal and research. The Florida Fish and Wildlife Conservation Commission and the South Florida Water Management District run the Python Elimination Program. This program employs skilled contractors and trained hunters to actively search for and humanely remove the snakes from public lands. This direct removal is a labor-intensive but necessary approach, with thousands of pythons being taken out of the ecosystem since the program’s inception.
Research is a major component of the management strategy, with scientists exploring various tools to increase the low detection rate of the camouflaged snakes. One innovative method involves using “Judas” snakes, which are male pythons implanted with GPS trackers and released to lead researchers to breeding aggregations. Other efforts include evaluating the use of detector dogs and exploring whether pheromones can be manipulated to attract pythons for capture.