Something has been quietly emptying the Everglades. Burmese pythons — some stretching past 13 feet — have spent decades working through South Florida’s food web, consuming mammals faster than researchers can count them.
In 2022, biologists Michael Cove and Jeremy Dixon started noticing something strange at Crocodile Lake National Wildlife Refuge near Key Largo. The GPS collars they’d fitted on opossums kept going silent — sending back faint mortality signals from somewhere deep in the refuge. When the researchers went to retrieve them, the collars weren’t on the ground.
They were inside snakes.
A mortality signal with a 13-foot surprise inside
Cove and Dixon weren’t hunting pythons — they were studying how small mammals navigate the refuge. The mortality alerts were an unwanted interruption. But the pattern kept repeating: a collar goes quiet, a signal pulses faintly from somewhere in the brush, and then the researchers wade in to find a large snake with a suspiciously recent meal inside it.
The snakes they encountered weren’t small. Every python recovered this way measured over 8 feet, and the largest stretched to around 13 feet — a predator capable of consuming a collared animal whole, GPS hardware and all. For Cove and Dixon, the initial reaction shifted quickly from surprise to something more deliberate.
From accidental finding to deliberate strategy
If pythons were already eating the collared animals, why not use that to drive removal? That logic turned an inconvenient field observation into a purposeful tracking method. Instead of treating consumed collars as lost equipment, the team began treating mortality signals as leads.
The ethical question came up immediately. Were researchers putting animals in danger by deploying them as bait? Dixon pushed back on that framing. “We’re not putting these animals out there and in harm’s way,” he told the South Florida Sun Sentinel. “Harm’s way is there. We’re just documenting what is happening.” The refuge already has a python problem severe enough to consume local wildlife at a steady rate — the collars simply make those losses visible, and actionable.
Opossums turned out to be a better fit for the program than raccoons. They’re more abundant in the refuge and willing to push deep into backwater swamp habitat where pythons concentrate. Raccoons were harder to handle and less likely to range into the areas where detections mattered most.
Cheaper collars, grant funding, and a growing team
The idea might have stayed a curiosity if the cost of GPS collars hadn’t dropped sharply. Not long ago, a single collar ran around $1,500. That price has since fallen to roughly $190 per unit — a reduction that transformed the program from a thought experiment into something scalable.
Cove and Dixon secured grant funding from the South Florida Water Management District, which operates its own python elimination program. That support gave the project financial footing and institutional backing. They also brought in A.J. Sanjar, a graduate researcher from Southern Illinois University, adding capacity to what had started as a two-person observation.
Eighteen pythons removed — and counting
The results so far are concrete. The team has removed at least 18 Burmese pythons using the opossum-collar method, every one of them over 8 feet long. The largest, at around 13 feet, represents exactly the kind of mature, established snake that’s hardest to locate through conventional means.
Currently, 32 GPS-collared opossums are deployed across the refuge. The team is aiming for at least 40 animals in the field by peak summer, when python activity tends to increase. The pace of consumption has been striking: some collared opossums have been eaten within two weeks of release, which reflects how densely pythons are distributed in certain parts of the refuge.
Dixon has been candid about the ceiling on what’s possible. With unlimited funding, he envisions hundreds of collared opossums working across the landscape simultaneously. For now, the program scales with what the budget allows.
Where this fits in Florida’s python-fighting toolkit
The opossum method joins a toolkit that already includes drones, thermal cameras, robotic decoys, and GPS-implanted male “scout snakes” that lead researchers to breeding aggregations. Scout snakes have proven especially effective in and around the Everglades, exploiting python social behavior during mating season. The opossum approach complements that strategy by targeting pythons year-round, wherever prey animals happen to move.
What the technique also does, in a low-key way, is illustrate the scale of the problem. When a collared animal disappears inside a snake within two weeks of release — not once, but repeatedly — it confirms that pythons aren’t a fringe presence in the refuge. They’re woven into it. Researchers and wildlife managers will be watching closely to see whether this method can be expanded, refined, and eventually deployed beyond Crocodile Lake to other parts of South Florida where the snakes have taken hold.