Burmese Pythons Are Disappearing In Florida - Scientists Just Found The Real Killer

Added: 2026-05-25

[00:00:00]In December of 2022, a wildlife biologist named Ian Bartoszek of the Conservancy of Southwest Florida was tracking a Burmese python through Big Cypress National Preserve in Southwest Florida when his radio receiver led him to a body.

[00:00:17]The snake was large. It was a tracked animal fitted with a transmitter as part of the Conservancy's long-running invasive python research program.

[00:00:27]Bartoszek had been following its movements for months. He knew approximately where it should be.

[00:00:33]The signal led him to the right location.

[00:00:36]But what he found, lying among the saw palmettos, was not the live snake he had been expecting to relocate.

[00:00:43]The body [music] was intact.

[00:00:46]The hide had not been broken open.

[00:00:49]The animal had not been opened up by any of the scavengers, including vultures, raccoons, and alligators that would normally process a dead snake of that size in the Florida wilderness within hours.

[00:01:02]The carcass was, by every external measure, undamaged.

[00:01:07]The head was missing.

[00:01:09]There were no drag marks. No signs of a long struggle.

[00:01:13]>> [music] >> No predator visible in the immediate vicinity.

[00:01:17]The python had been a large adult. The kind of animal that, until very recently, had no documented natural enemies in the Everglades ecosystem.

[00:01:26]>> [music] >> It was an apex predator. It was supposed to be the thing other animals ran from.

[00:01:32]And yet, here it was.

[00:01:34]Decapitated.

[00:01:36]In one of the most carefully monitored sections of one of the most carefully monitored federal preserves in the United States.

[00:01:43]Without an obvious cause of death and without the obvious culprit anywhere in sight.

[00:01:47]Bartoszek collected the carcass. He checked his trail cameras.

[00:01:52]>> [music] >> What the trail cameras eventually showed him, combined with parallel work being done by a federal research team about an hour's drive to the east was the beginning of one of the most consequential ecological findings of the entire Florida python invasion.

[00:02:06]Something in the Everglades has started killing Burmese pythons. Not a person with a permit and a captive bolt pistol.

[00:02:12]Not a hunting contractor on the South Florida Water Management District payroll. Not a participant in the annual python challenge.

[00:02:20]Something native. Something that lives in the preserve. Something that [music] until very recently was supposed to have been on the python's prey list, >> [music] >> not the other way around.

[00:02:30]What scientists have actually found. How a 25-lb cat is killing 50-lb [music] snakes.

[00:02:37]Why in some specific zones of Big Cypress, [music] python detection rates are finally starting to drop. And why even with this finding, the crisis is not over.

[00:02:49]How the snakes got to Florida is a hurricane story.

[00:02:53]On August 24th, 1992, a Category 5 hurricane named Andrew made landfall in Southern Florida.

[00:03:02]Andrew was one of the most destructive hurricanes in modern American history.

[00:03:06]It killed dozens of people. It leveled the town of Homestead. It tore through every form of human infrastructure between Biscayne Bay and the eastern edge of Everglades National Park.

[00:03:19]One of the structures Andrew destroyed was a Burmese python breeding facility near Homestead.

[00:03:25]The facility held captive snakes intended for the exotic pet trade.

[00:03:29]When the building came apart in the storm, the snakes inside it scattered.

[00:03:34]Some were killed in the wreckage. Some were captured. Some, almost certainly, made it into the surrounding swamp and disappeared.

[00:03:42]Hurricane Andrew is not the only origin story for the Florida python population.

[00:03:48]Released pets, deliberate dumps from owners who could no longer manage adult snakes and other smaller releases all contributed.

[00:03:57]But Andrew is the most cited founding event.

[00:04:00]The moment when a captive population in significant numbers first entered the Everglades in conditions favorable for them to survive.

[00:04:10]The first confirmed wild Burmese pythons in the Everglades were documented 3 years later.

[00:04:16]In 1995, biologists collected a 7-ft adult and a hatchling near West Lake at the southern tip of Everglades National Park.

[00:04:26]The hatchling was the significant part.

[00:04:29]It meant that by 1995, the python population was not merely surviving.

[00:04:35]It was breeding.

[00:04:36]A self-sustaining wild population of one of the world's largest snake species had established itself in a North American National Park.

[00:04:46]27 years later, the published literature would describe that population in the language of ecological catastrophe.

[00:04:53]The 2012 US Geological Survey study led by Michael Dorcas of Davidson College was the moment the scientific community first quantified what the pythons had done.

[00:05:05]The paper was published in the Proceedings of the National Academy of Sciences.

[00:05:09]Across the python invaded areas of the greater Everglades ecosystem, the study documented declines on the order of 99% in raccoon and opossum populations.

[00:05:21]Marsh rabbits had essentially disappeared.

[00:05:24]Foxes had essentially disappeared.

[00:05:26]White-tailed deer had become rare where they had once been common.

[00:05:31]A follow-up study in 2015 made the cause and effect relationship explicit.

[00:05:37]Biologists from the USGS, the Florida Fish and Wildlife Conservation Commission, and the University of Florida released 95 adult marsh rabbits into python invaded zones. They fitted the rabbits with transmitters and tracked them.

[00:05:51]Within 11 months, pythons had killed 77% of them.

[00:05:56]The translocation study was definitive.

[00:05:59]The rabbits were not declining because of habitat loss or disease or climate change.

[00:06:04]The rabbits were declining because they were being eaten.

[00:06:08]By 2020, Bar Toshek [music] had publicly stated that the list of native Florida species being eaten by Burmese pythons had grown to approximately 85.

[00:06:19]"It's easier," he told reporters at the time, "to make a list of what pythons are not eating."

[00:06:25]In October of 2022, Bar Toshek's team published the first photographic documentation of a Burmese python in Florida consuming an adult white-tailed deer.

[00:06:37]A 115-lb snake swallowing a deer that weighed almost as much as the snake itself.

[00:06:44]The image went around the world. It became, briefly, the visual shorthand for what the invasion had done to the Florida ecosystem.

[00:06:52]This is the context in which the bobcat finding needs to be understood.

[00:06:57]The pythons were not in retreat. They were not collapsing.

[00:07:02]They were the most consequential invasive vertebrate established in modern North American history.

[00:07:08]Spread across thousands of square miles of protected federal wilderness.

[00:07:13]Breeding with a reproductive arithmetic that made eradication by removal essentially impossible.

[00:07:19]The arithmetic is worth dwelling on for a moment.

[00:07:23]Female Burmese pythons in Florida have been documented producing clutches of up to 87 eggs in a single reproductive season.

[00:07:32]A single female in a single year can produce more offspring than most native predators produce in a lifetime.

[00:07:40]The South Florida Water Management District's Python Elimination Program, launched in 2017, pays hunters by the hour and by the length of the snake they bring in.

[00:07:51]The Florida Python Challenge, run annually by the State Fish and Wildlife Conservation Commission since 2013, attracts hundreds of participants competing for cash prizes.

[00:08:02]The 2024 Python Challenge involved over 850 participants.

[00:08:08]It removed approximately 200 pythons from public lands.

[00:08:12]The cumulative removal across all Florida programs has now exceeded 10,000 pythons.

[00:08:19]That number sounds enormous. It is enormous. And it is, against the reproductive output of the established wild population, nowhere close to enough.

[00:08:31]Every season, the snakes that have not been caught lay clutches that more than replace the 10,000 removed since the program began.

[00:08:40]Human removal is keeping the population from accelerating into worse territory.

[00:08:45]It is not, by itself, reversing the invasion.

[00:08:49]That was the situation as of the early 2020s.

[00:08:54]A spreading invasion, a devastated native mammal fauna, a removal program that was running as hard as it could and still not gaining ground.

[00:09:04]Then, in certain zones of Big Cypress National Preserve, something started to change. The researchers who noticed it first were not looking for it.

[00:09:14]The US Geological Survey's Wetland and Aquatic Research Center, based in Gainesville, Florida, runs the long-standing federal research program on Florida invasive pythons.

[00:09:25]In the summer of 2021, USGS biologists were monitoring a known python nest at Big Cypress as part of their routine surveillance work.

[00:09:36]The nest had been located. The female was incubating.

[00:09:40]The trail cameras had been set up around the site to document the basic ecology of nest defense.

[00:09:46]How often the female left the eggs.

[00:09:49]How long she was gone.

[00:09:51]How she behaved when she returned.

[00:09:53]The footage that came back was not what anyone had expected.

[00:09:57]Between June 1st and September 9th, 2021, the cameras captured a male bobcat, Lynx rufus, the native North American small cat, approaching the python nest on multiple visits.

[00:10:10]The first visits, when the female python was away from the nest, showed the bobcat consuming, trampling, caching, and uncovering the eggs.

[00:10:21]The bobcat was not just curious.

[00:10:23]He was working on the nest.

[00:10:25]>> [music] >> He was destroying it.

[00:10:27]Then, in one of the most fully recorded sequences ever captured at a Florida python nest, the bobcat was present when the female returned.

[00:10:36]The female was an estimated 85-lb snake.

[00:10:39]The bobcat weighed approximately 20 lb.

[00:10:42]The snake was more than four times the cat's body weight.

[00:10:46]Burmese pythons of that size routinely kill and consume mammals significantly larger than a bobcat.

[00:10:52]By every prior assumption about the python versus native predator interaction in the Everglades, the bobcat should have either fled or been killed.

[00:11:01]He did neither.

[00:11:02]The cameras recorded the bobcat and the python exchanging strikes at the nest site. The cat moved at angles the snake could not follow.

[00:11:10]He used his speed against the python's reach.

[00:11:13]He held his ground.

[00:11:14]He did not flee. He did not allow himself to be caught.

[00:11:18]When the biologists arrived to relocate the female, they found the nest destroyed. [music] They counted 42 inviable or destroyed eggs.

[00:11:28]That was the first documented predation of Burmese python eggs anywhere in Florida. Not in the Everglades, anywhere.

[00:11:36]In the more than 25 years since the wild population had established itself, no native predator had been recorded [music] depredating a python nest until that bobcat on that camera >> [music] >> in the summer of 2021.

[00:11:51]The team that documented the encounter included Andrea Curalo of the USGS Wetland and Aquatic Research Center and colleagues.

[00:12:00]They wrote the journal Ecology and Evolution.

[00:12:04]The paper was published in February 2022.

[00:12:07]It used the formal ecological term for what they had observed.

[00:12:12]Intraguild predation.

[00:12:14]The phrase describes interactions between predators that also compete for the same prey base.

[00:12:20]Bobcats and pythons in the Everglades are both predators. They both eat the same small mammals, rabbits, [music] opossums, raccoons.

[00:12:29]They are, in ecological terms, in the same [music] guild. And one of them had just started eating the other.

[00:12:35]The 2022 paper was carefully written.

[00:12:38][music] It did not claim that bobcats were going to drive the Florida python population to extinction.

[00:12:45]It did not claim that the invasion was over.

[00:12:49]What it did claim, [music] and this was the part that started to change the conversation, was that an intraguild predation event of this kind between a native carnivore and an established invasive snake of this size had now been documented under controlled scientific observation.

[00:13:06]The event existed. It was photographed.

[00:13:09]It was published.

[00:13:10]And it was not the only one.

[00:13:13]About an hour's drive to the west of Big Cypress in the watershed that drains toward Naples and the Gulf of Mexico, the Conservancy of Southwest Florida's research team had been doing parallel work for more than a decade.

[00:13:26]The Conservancy's program is built around what the researchers call scout snakes.

[00:13:32]Male Burmese pythons fitted with transmitters >> [music] >> and released back into the wild during breeding season, where they lead the team to receptive females.

[00:13:43]The scout snake program has been the most productive python research methodology of the last 20 years.

[00:13:50]It has produced most of the major recent findings on Florida python ecology, the deer predation documentation, the 85 species prey list, the long-term clutch size data that has shaped the reproductive arithmetic of the invasion.

[00:14:06]Bartoszek has led the field team since the program's early years.

[00:14:10]He has tracked pythons for more than 12 years. In the period running from late 2022 onward, his team began finding things in the field that had not been findable before. The decapitated python was one of them, found in December 2022.

[00:14:26]Body intact, head removed.

[00:14:29]No obvious cause of death visible at the carcass.

[00:14:33]Bartoszek's cameras subsequently caught a bobcat feeding on the remains and returning to the carcass over multiple visits to cache and refeed.

[00:14:41]The carcass was not random scavenging on a snake that had died of other causes.

[00:14:47]The trail camera record, taken together with the carcass condition, indicated active predation.

[00:14:53]The bobcat was working the kill the way bobcats work kills they have made themselves.

[00:14:58]The pattern was emerging in multiple locations. In a separately documented case from Bartoszek's team, a roughly 25-lb bobcat killed and cashed a 52-lb Burmese python.

[00:15:10]That single case became the most quoted single statistic of the entire emerging finding.

[00:15:17]A cat that weighed less than half what the snake weighed.

[00:15:20]A small native carnivore by any measure.

[00:15:22]>> [music] >> The kind of animal that in a park with no pythons would itself be among the smaller predators competing with foxes and large hawks for shared prey.

[00:15:32]It had killed and processed a snake more than twice its body weight.

[00:15:37]The accompanying line Bartoszek gave to the press has become the slogan for the entire phenomenon.

[00:15:44]A win for the home team.

[00:15:46]Then in a separate necropsy performed at the Conservancy's facility on a python collected through routine fieldwork, Bartoszek's team opened the snake's digestive tract. They recovered intact bobcat claws.

[00:16:00]What the bobcat claws found inside the python necropsy mean is the part of the story most coverage has never been given.

[00:16:07]The claws do not contradict the trail camera findings. They complete them.

[00:16:13]The predation relationship between the two animals runs in both directions.

[00:16:17]>> [music] >> Some bobcats are killing pythons.

[00:16:20]Some pythons are killing bobcats.

[00:16:23]The interaction is not a one-sided story in which the native cat is simply driving back the invader.

[00:16:29]It is an actual ecological engagement.

[00:16:32]A novel predator versus predator relationship established in real time in which both species are sometimes the predator and sometimes the prey.

[00:16:42]This is what the 2022 paper's intraguild predation framing actually means.

[00:16:48]It is not that the bobcats have won. It is that bobcats and pythons are now in some specific parts of Southwest Florida and Big Cypress engaged with each other as ecological peers competing for the same prey. Depredating each other's young, occasionally killing each other's adults in the specific zones where this engagement has been most intensively documented, python detection rates have begun for the first time in the history of the invasion to drop.

[00:17:17]It is important to be honest about the scale of the effect. The consensus position from the researchers who have actually published on this, from Carillo at USGS, from Bartoszek at the Conservancy of Southwest Florida, is that the bobcat findings are encouraging, but do not currently offset python reproduction at the level of the overall Florida population.

[00:17:40]The pythons are still laying clutches of up to 87 eggs per female.

[00:17:45]The total population across the greater Everglades is still very large.

[00:17:50]The bobcats are not driving the snakes extinct.

[00:17:53]They are, however, applying a measurable downward pressure in the specific zones where the engagement has been documented.

[00:18:01]The engagement appears to be spreading.

[00:18:04]The mechanism is straightforward when you look at the trail camera record.

[00:18:08]Adult Burmese pythons are vulnerable in specific situations that the snakes themselves cannot easily avoid.

[00:18:15]During incubation, a female python is essentially anchored to her nest for weeks, leaving only for short foraging trips.

[00:18:23]During those absences, the eggs are undefended.

[00:18:26]After a large meal, the snake is digesting and physically immobile for days.

[00:18:32]After consuming a deer or a large mammal, the python's body is distended and slow.

[00:18:38]During shedding, the snake's vision is reduced as the eye scales cloud over before sloughing.

[00:18:44]Each of these states represents a window.

[00:18:47]And bobcats, >> [music] >> quick, intelligent, and willing to work a carcass over multiple visits, have apparently learned somewhere to take advantage of those windows. The somewhere matters.

[00:18:59]There is a real ecological theory being tested here.

[00:19:03]It is one of the most interesting ideas in invasion biology.

[00:19:07]Native ecosystems can, in principle, [music] develop counter pressures against invasive species over time.

[00:19:14]The classic example is the Australian rainbow bee-eater, which learned, after several decades, to handle invasive cane toads.

[00:19:23]Toads that had been ecological disasters for native Australian predators because their skin secretions were toxic.

[00:19:30]The bee-eaters figured out how to dispatch them safely.

[00:19:34]Other Australian species, including some birds and rats, have since developed similar adaptations.

[00:19:40]The cane toad invasion has not been reversed by these adaptations, but it has been blunted in specific regions where the adaptations have taken hold.

[00:19:50]The Florida bobcat python interaction is being studied by the researchers who have published on it as a potential analogue.

[00:19:59]A native carnivore working out, on a generational timescale, how to engage with a large invasive snake that did not exist in its ancestral environment.

[00:20:10]The cats that are succeeding are presumably teaching the technique by some combination of observation and direct lineage to their offspring.

[00:20:19]The behavior is spreading. The success rate is climbing.

[00:20:23]The pythons, in the specific zones where this is happening, are paying a cost.

[00:20:28]There is also a second native predator pushing back against the pythons that has received less attention.

[00:20:35]The Conservancy of Southwest Florida has separately documented native cottonmouth water moccasins, Agkistrodon piscivorus, the heavy-bodied semi-aquatic pit viper of the southeastern wetlands, preying on Burmese python hatchlings.

[00:20:51]Hatchling pythons are small. They are about 50 to 60 cm long. They are slow growing in their first weeks, initially relying on internal yolk stores. They are vulnerable to native predators in ways the adults are not.

[00:21:07]The cottonmouths, which inhabit the same wet habitats the python hatchlings emerge into, have apparently begun including them as prey.

[00:21:15]This is a less publicized form of native pushback than the bobcat story.

[00:21:20]But it is documented, photographed, and real.

[00:21:24]The hatchlings are being eaten by a native snake the adults would have ignored.

[00:21:28]Put both findings together and the picture starts to look different from what it looked like 5 years ago.

[00:21:35]Adult pythons in some zones are being killed by bobcats.

[00:21:39]Python hatchlings in those same zones are being eaten by cottonmouths. The python eggs are being destroyed by bobcats during the incubation window.

[00:21:48]The reproductive arithmetic that made the invasion seemingly unstoppable, the 87 egg clutches and the rapid generational turnover, is being eroded in specific places by native predators that have apparently figured out how to feed on every stage of the python life cycle.

[00:22:06]The pythons are not gone.

[00:22:08]The pythons are not, as a Florida population, in retreat.

[00:22:13]The most honest statement of where we are, as of the most recent USGS synthesis paper from 2023 by Goozy and colleagues and published in the journal Neobiota, is that the population is still very large. The impacts on native fauna are still ongoing >> [music] >> and the management challenge remains severe.

[00:22:34]The bobcat finding is encouraging.

[00:22:37]>> [music] >> It is not a solution. What it is, however, is the first piece of evidence that the Everglades ecosystem is doing what ecosystems sometimes do under invasion pressure. It is adapting. It is learning. It is producing native predators that can engage [music] with the invader on something like equal terms in specific places, in specific situations.

[00:23:01]The intraguild predation framework [music] that Krylov's 2022 paper laid out is now being applied to data sets across multiple research programs in Southwest Florida.

[00:23:12]The picture is being refined. The mechanism is being studied. The trajectory is being projected. And the headless python that Bartoszek found in December of 2022 has its answer.

[00:23:25]The killer was a bobcat. The cat had taken the head. A typical bobcat behavior with prey carcasses in which the most calorically dense and most readily consumable parts of the kill are processed first >> [music] >> and had then returned to cache the rest of the body for later feeding.

[00:23:43]The trail camera footage confirmed [music] it.

[00:23:46]The pattern matched the December findings.

[00:23:48]The same cat, or one of its kind, had been processing pythons in that part of Big Cypress as a regular part of its hunting routine for at least the previous year.

[00:23:58]The python that had been one of the largest, most successful invasive vertebrates ever established in a North American ecosystem >> [music] >> had been killed by a member of a species that, on every prior assumption, should have been part of its prey.

[00:24:12]That is the actual finding. Not coyotes attacking python skulls and eating brains. Not river otters wiping out entire nests.

[00:24:21]The peer-reviewed and research organization documentation does not support those storylines.

[00:24:27]The published evidence supports something more specific and, in some ways, more remarkable.

[00:24:33]A native cat that is, on average, less than half the body weight of the snake it is now successfully killing has, since roughly 2021, become the first systematically documented native predator of adult Burmese pythons in Florida.

[00:24:50]The story is still being written.

[00:24:52]Every new field season at Big Cypress, every new trail camera deployment by Bartoszek's team, every new necropsy at the Conservancy of Southwest Florida adds another data point.

[00:25:05]Some of the data points show pythons killing bobcats. Some of them show bobcats killing pythons.

[00:25:12]The relationship is real. The engagement is real.

[00:25:15]The trajectory in the zones where the engagement is concentrated is starting to bend in favor of the native species for the first time in the entire history of the invasion.

[00:25:26]There is, in all of this, a piece of context worth holding on to.

[00:25:31]The native species that depends most heavily on the same medium mammal >> [music] >> prey base the pythons devastated is not the bobcat.

[00:25:39]It is the Florida panther, Puma concolor coryi, the endangered subspecies of mountain lion that survives only in a small remnant population in Southwest Florida, and competes directly with the bobcats for the same prey.

[00:25:56]The pythons, by collapsing the rabbit, raccoon, [music] and opossum populations, had been quietly starving the panther's food base for years.

[00:26:06]Anything that pushes back against the pythons pushes back indirectly in favor of the panther.

[00:26:12]The bobcat finding matters not just because it is interesting on its own terms.

[00:26:17]It matters because the home team it represents includes a species that, until very recently, had been quietly going down with the rest of the Everglades native mammals.

[00:26:27]The bobcat is a win.

[00:26:30]The cottonmouth feeding on hatchlings is a second win.

[00:26:34]The intraguild predation framework is producing data that is being read by researchers, managers, [music] and policy makers as evidence that the Everglades, against very long odds, may be developing the kind of internal counter pressure that other ecosystems have developed against other invasive species over generational time scales.

[00:26:55]It is not over.

[00:26:57]The pythons are still there. The clutches are still huge. The python elimination program is still going to be paying contractors by the hour and by the foot of snake for the foreseeable future.

[00:27:10]The annual python challenge will continue.

[00:27:13]The native mammal populations are still suppressed in the worst affected zones.

[00:27:18]The deer-eating python in Bartoszek's 2022 photograph is still representative of what a large adult Burmese python in Southern Florida is capable of.

[00:27:28]But the headless python was a real animal.

[00:27:31]The trail camera footage of the male bobcat at the nest in the summer of 2021 was real footage.

[00:27:38]The 25-lb cat that killed the 52-lb snake was a real cat and a real snake.

[00:27:45]The bobcat claws found inside the python necropsy were real claws.

[00:27:50]The cottonmouth hatchling predation is real predation.

[00:27:54]The 2022 paper in Ecology and Evolution is a real paper.

[00:28:00]The 2023 USGS synthesis paper is a real paper.

[00:28:05]For the first time in three decades of a worsening invasion, the Everglades has produced documented native predators that are killing Burmese pythons. The pythons are not yet losing, but they are finally fighting an actual war instead of a one-sided occupation.

[00:28:22]Somewhere in Big Cypress National Preserve right now, a 25-lb bobcat is doing what no native Florida predator was doing 5 years ago.

[00:28:32]He is treating an 85-lb Burmese python the way the pythons have been treating his prey base for a generation.

[00:28:39]He is hunting it.

[00:28:41]What the pythons did to the Everglades native mammals over 20 years is what the ecological literature has documented in painful detail.

[00:28:50]What the bobcats are doing, back to the pythons in the zones around Big Cypress, is what the trail cameras have only just begun to record.

[00:29:00]What the Everglades has produced, by every measure of the engagement now being studied by Curallo and Bartosik and the rest of the field, is the first piece of native counter pressure against the invasion in three decades.

[00:29:13]And the first evidence that the ecosystem itself, eventually, was always going to be the one to write the next chapter of the story.