The Florida Everglades is a sprawling wetland ecosystem, globally recognized for its unique biodiversity and an array of wildlife, including various reptile species. This subtropical wilderness is home to alligators, native snakes, and other creatures uniquely adapted to its marshy environment. The presence of large snakes in this region often sparks public curiosity and concern, leading to questions about which species truly inhabit these wetlands.
Anacondas and the Everglades
Green anacondas are not an established invasive species in the Everglades. While sporadic sightings have occurred in Florida, including near the Everglades, these instances are typically attributed to escaped or released pets.
The Florida Fish and Wildlife Conservation Commission (FWC) tracks non-native species. While green anacondas are listed as an invasive species, they are not currently established in Florida. Authorities maintain that viable breeding populations have not taken hold. Encounters with green anacondas in Florida are unlikely, especially compared to Burmese pythons.
Anacondas Versus Pythons
Anacondas and pythons, while both large constrictor snakes, originate from different parts of the world and exhibit distinct characteristics. Green anacondas (Eunectes murinus) are native to South America, primarily found in the Amazon and Orinoco river basins. They are highly aquatic, preferring slow-moving rivers, swamps, and flooded forest floors, spending significant time submerged with their eyes and nostrils positioned on top of their heads. Green anacondas are known for their immense girth and weight, reaching lengths over 30 feet and making them the world’s heaviest snake. Their coloration is olive-green with dark oval spots, providing camouflage in their watery habitats.
Burmese pythons (Python bivittatus), in contrast, are native to Southeast Asia. They are also large constrictors, with adults in Florida averaging between 6 to 9 feet, though some can exceed 18 feet. Their appearance is characterized by a tan base color with dark brown blotches bordered by black. Burmese pythons are semi-aquatic but are also found on land and in trees. Unlike anacondas, Burmese pythons are longer but less bulky than a green anaconda of comparable length.
The Everglades’ Established Constrictor
The true large invasive constrictor issue in the Everglades centers on the Burmese python. These snakes became established in South Florida primarily through the exotic pet trade, with many being released by owners who could no longer care for them due to their large size. A significant event contributing to their population boom was Hurricane Andrew in 1992, which destroyed a python breeding facility, releasing numerous snakes into the adjacent wetlands. The warm, humid climate and abundant prey in the Everglades provided an ideal environment for these non-native predators to thrive.
Burmese pythons have since become a major threat to the native ecosystem of South Florida, preying on a wide variety of native birds, mammals, and even reptiles, including alligators. Their presence has been linked to severe declines in mammal populations within Everglades National Park; for instance, studies have shown declines of 88% to 100% in sightings of raccoons, opossums, bobcats, and rabbits between 1996 and 2011. These pythons also compete with native predators for food and resources and can introduce non-native parasites to native snake populations.