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The Problem with Pythons

FOF March 27, 2012 Armchair Interpretive Walks

by Dennis Giardina

It could be said that if you haven’t heard about pythons in the Everglades yet, you’d have to have been hiding under a rock. If that rock happened to be in South Florida, you may still have become aware of the presence of pythons because there’s a chance you’d be sharing that cool, dark shelter with one of them. Over the past ten years there have been many very good articles written about pythons. There have been interesting, informative vignettes on radio and television programs but now it seems that the hype machine is rolling wide-open, pummeling hapless consumers of information with sensational anecdotes and images of an invasion of giant, malevolent snakes. The reality of the situation may be somewhat less shocking than portrayed by the sensationalistic media but no less concerning, albeit for different reasons. Let’s start close to home. Are there pythons in Fakahatchee and, if so, what threats do they pose?

Yes Virginia, there are pythons in Fakahatchee. We know this because one was collected by an exotic plant treatment crew in January of 2007 at the borrow pit lakes area in the northeast corner of the preserve. Another was observed floating upside down in the canal on the south side of US 41 by Mike Owen about a month ago, most likely hit by a vehicle. The epicenter of the spreading population of Burmese pythons is Everglades National Park. There are several theories of how they got there but whether the population originated by a breeding facility destroyed by Hurricane Andrew or as a result of multiple separate releases or both – the damage has been done. That SE Florida population has now spread in every direction aided by the network of canals that crisscross South Florida. For the past ten years Burmese pythons have been observed and collected in SW Florida, especially in the Collier-Seminole State Park – 6L Farms – Rookery Bay NERR – Marco Island Airport area. Some suspect that this SW Florida population may be the result of a separate introduction of Burmese pythons but regardless, there seem to be more sightings and collections every year. Mike Owen and I feel that the number of pythons that occur in Fakahatchee at this point is very low, filtering in up from US 41, down from I-75 and over from Big Cypress. We have yet to receive a report of a python on Janes Scenic Drive. When that happens, we will have to reconsider our population estimate.

The threats that pythons pose have more to do with their impact on native wildlife, especially local mammal and bird populations and less with any direct danger to humans. Pythons are not accustomed to eating us and even the largest Burmese pythons would have a hard time getting their jaws around even the narrowest of human shoulders to swallow one of us. They, like any animal, when threatened or cornered will defend themselves. Their bite/constrict/swallow feeding behavior is different from their defensive behavior which is more like other snakes: they coil up, inflate their body and raise their head, making a loud hissing sound. There are few animals (other than humans) that would continue to approach a large python in full-blown defense display but if one were to do so, the python would then strike repeatedly. Unlike animals, human beings usually wear clothes and if the curved teeth of the striking python were to snag a pant leg or a shirt sleeve, the python would not be able to simply release it and would try to pull its head back into its coils and perhaps it would go into wrap and constrict mode. I don’t know but if you are afraid to walk in the woods because of the danger of being bitten or eaten by a python, all I can say is don’t be, they are not going to bother you.

Skip Snow, the Wildlife Biologist at Everglades National Park who has been dealing with pythons longer than anyone, has noticed something concerning. It seems that small mammal populations, everything from marsh rabbits to bobcats seem to be on the decline along the main road inside the park. In areas where there were numerous sightings and sign of animals like tracks and scat, now seem to be much less or absent. Because circumstantial evidence does not a case make, Skip, UF Scientist Frank Mazzotti and others have embarked upon a study to see if they can prove that this observed decline has been caused by pythons alone, or whether its due to other factors like disease – or both. It’s hard to imagine that a population of pythons, likely numbering in the thousands wouldn’t have a noticeable impact upon a native mammal fauna unaccustomed to their predation but it’s our job to back up our feelings, insights and observations with data. That is science and there is (in terms of the physical world) no better arbiter of truth.

It seems to me and most of my colleagues that pythons and other large exotic reptiles like monitor and tegu lizards are here to stay. We think they will continue to spread, eventually throughout the entire peninsula. Cold weather events will knock them back, but they will self select for more cold hardiness over time as well. Native mammals and birds will have to develop strategies to avoid being eaten by them so that enough of them are able to reproduce and persist as species. Natural areas managers and scientists will continue to innovate methods to trap and kill them to keep their population levels low and reduce the average size of individuals but there is no magic bullet. There are however many tools in the toolbox. One particularly promising one is the use of dogs trained to sniff out pythons. A pilot project last year, using two Labrador retrievers from the Auburn University Canine Unit showed that in certain applications they were tremendously successful at locating hidden individuals and with targeted seasonal surveys, many pythons could potentially be removed from the environment in a short amount of time. Currently there is so much information available that if you want to read more, Google “Burmese pythons in Florida.”

Dennis Giardina is the Everglades Region Biologist for the Florida Fish and Wildlife Conservation Commission and was formerly the Park Manager of Fakahatchee Strand Preserve.