Zoo Miami Explores Innovative Techniques To Manage Invasive Pythons

Jul 22, 2019

Invasive snake populations in the Everglades continue to have devastating impacts on the ecosystem. 

Burmese Pythons, North African Pythons and Boa Constrictors have reduced the population of fur bearing animals by 99 percent, according to scientists. Since 2007, Zoo Miami has been working with the National Park Service, the United States Geological Services and the University of Florida to manage and eradicate invasive species from the Everglades.

Frank Ridgley is a wildlife veterinarian who serves as the head of the Conservation and Research Department at Zoo Miami. He’s spearheaded programs to insert tracking devices into snakes so researchers have a better understanding of where they’re breeding and traveling within the Everglades. Ridgley and WLRN Environment Reporter Jenny Staletovich spoke with Luis Hernandez on Sundial about the scope of the problem these invasive species pose and what’s being done to manage or eradicate them.    

WLRN: We have an effort statewide to try to get rid of this invasive species. Do we know how many Burmese Pythons are actually in the wild?

Staletovich: We don’t know because they’re so hard to find. Getting an estimate on the sheer number is difficult. I believe they’ve tried to model it out and Frank told us at this point we’re past trying to eradicate, this is about management. They sort of measure the impact of pythons by looking at what’s missing from the marshes. That’s how they know how far they’ve spread in addition to the sightings.

Frank, you’ve launched another project now dealing with pheromones. Alright, help me understand how this works.

Ridgley: This has been talked about in the scientific community for years. Because once we discovered that  they form breeding aggregates at a certain time of year we know there has to be some very powerful attraction. And it turns out that the female snake, when she’s receptive and she sheds her skin, she lets off this powerful pheromone, this chemical attractant that the males find irresistible and will come and find her and then the males compete for breeding.

So we always thought, if we could figure out what that chemical compound is and we could use it and make the snakes come to us instead of us trying to find them in this incredibly difficult habitat, that would be a pretty good tool at helping us remove a lot of snakes at once. So they haven’t been able to synthetically produce this pheromone or isolate it yet. But then there’s this researcher named Rocky Parker who wrote one of the best titles of a scientific paper I’ve ever heard. It was called How to Make a Sexy Snake.

And it’s a very serious scientific paper and his research is serious but there was a great title. And he did this with garter snakes, where he used a hormone to manipulate one of the snakes to produce this pheromone and it was very powerful. The researchers at USGS and National Park Service are trying to figure out if we can make this happen [with] Burmese pythons. They’re very different snakes - a garter snake and a Burmese python. They split off a long time ago in the evolutionary tree. But if we could make that happen maybe that’s another tool in the arsenal ... maybe we have a transmitter snake that’s also producing these pheromones. So it’s just going through the Everglades collecting other snakes. It it makes it more efficient. Anything we can do to make it more efficient is a great tool.

How are you going to rate success?

Ridgley: I think it's about getting recovery of the species that have been killed off by the pythons. You can have localized effects, if you're intense like they're doing a lot in the southwest part of Florida and some local habitats that are important. And they're removing these snakes and it's probably having a big effect on those species to be able to recover. But I think overall, it's difficult. For some species like the North African python, there is a chance of eliminating that. It's on the lower part of what we call an invasion curve at the bottom, you have a chance of getting rid of early on.

And that's why it's so important for people to not release exotic animals and also report them if they see something unusual. But once you get on this curve and you get way up into kind of where they just exponentially explode then you move into management. And barring like a super cold winter or maybe some new biological technique where maybe it's a custom virus in the future that only targets Burmese pythons, we're limited on what we can come up with right now.