Samantha Smith first encountered PYBI029 in January 2019 after a farmer traced her tracks in the ash of a recently burned agricultural field on the outskirts of Sakaerat Biosphere Reserve, in Thailand. She treated the snake’s burn injuries with Neosporin and nicknamed her Daenerys, after the fireproof Game of Thrones character. A few weeks later, a veterinarian implanted the newly healed PYBI029 with a radio tracker, making her the fourth Burmese python in Smith’s study group of seven.
Seven may sound like a small number of subjects for a research project. It is. But Smith, a conservation biologist who’s been watching her serpentine subjects since 2018, can’t afford to track 20 snakes; she relies on donated or shared equipment. “No one wants to fund snakes,” said Caesar Rahman, a conservation biologist working in Bangladesh. “It’s not a priority species.”
In its native range from southeastern China and Vietnam across much of Laos, Cambodia, Thailand, Myanmar, and Bangladesh to parts of Bhutan, Nepal, India, and Indonesia, Python bivittatus is listed by the International Union for Conservation of Nature as vulnerable, one step from official endangerment. Habitat loss and degradation, the pet trade, and poaching have reduced the population by roughly a third over the past decade and more than half in 20 years. With tigers and leopards hanging on last threads, the snakes are one of the few remaining large carnivores in the region—and a relative enigma: “Not much is known about them,” Rahman said. The teams that have produced most of the research on Burmese pythons, sinking massive sums into the enterprise, operate halfway around the world, in Florida. They aren’t trying to save their subjects. They’re trying to kill them.
Rahman has been embedding radio trackers in Burmese pythons in Bangladesh’s Lawachara National Park since 2013, to monitor their movement and answer basic questions about their biology. How far can an individual python travel? What habitats do they prefer? What effect does relocating pythons from villages to forests have on their movement and survival?
That’s all fairly basic information, but Burmese pythons’ nocturnal and secretive lifestyle makes them tough to study. Once during fieldwork, Rahman struggled to track down a Burmese python even with its GPS location in hand. “We didn’t realize it was right there,” he told me. “We were practically standing on it.” It’s a common experience among python researchers. As Smith told me: “It’s definitely made me more careful of where I put my feet.”
While Smith and Rahman struggle to get funds for trackers, Florida wildlife officials have spent about $1 million annually trying to reduce the tens of thousands of Burmese pythons thriving across the state’s southern tip and preying on more than 65 of its native species.
Unlike in their native range, Burmese pythons in Florida are reviled as a so-called invasive species—a pest. As such, the snakes have become one of the prime examples of an increasingly common and paradoxical category of species that are considered invasive in one part of the world and endangered in another.
Burmese pythons arrived in Florida most likely through the pet trade during the late twentieth century. Since then, they have decimated the Everglades’ raccoon, opossum, bobcat, rabbit, fox, and rodent populations. The snake species uses extra-stretchy jaws and six rows of razor-sharp teeth to swallow prey—including herons, bobcats, and alligators—whole. As juveniles, they can scale trees. As adults, they’re capable of underwater submersion for up to 30 minutes. When researchers caught one of the largest-ever-recorded Everglades pythons in 2012, they killed all 17 feet of her and the 83 eggs she was carrying, with the full blessing of the state and federal government.
In their other efforts to cull Burmese pythons, officials have recruited and deployed pheromones, interns, dog detectives, and python hunters (both rookies and pros, who competitively cull snakes for all-terrain vehicles, cash prizes, and bounties). The state also holds amnesty days so pet owners can freely surrender unwanted pythons instead of setting them loose.
Since 2000, U.S. biologists have also discovered a lot about the species and its environmental ripples in Florida. By sifting through 14 pounds of poop excavated from the gut of a 14-foot snake, researchers could document what the snake considered a decent meal: three white-tailed deer. They’ve investigated python lung parasites, studied hatchlings’ tolerance of saltwater, and tested acetaminophen as a possible python poison. Ongoing projects explore whether molecular tools could help wildlife officials trace and control pythons. “We hope that we can find how to best use this animal’s biology against it,” Andrea Currylow, a research ecologist with the United States Geological Survey, told me.
There’s one thing Florida scientists lack as they lead the containment efforts: a baseline understanding of how Burms, as they’re called, behave in the wild. And that’s why, despite their opposing conservation aims, researchers in Florida and researchers in Southeast Asia maintain a close, collegial relationship from halfway across the planet.
“Any small aspect that we find out about the species in the native range could potentially apply and spark some ingenuity for people trying to control them,” said Scott Trageser, a conservation biologist and partner in Rahman’s Bangladeshi research effort. In fact, U.S. conservation officials helped get Rahman’s project off the ground in 2013 with a donation of $2,000 worth of radio transmitters—transmitters like the ones they used to locate and kill the large female in 2019. When it comes to Burmese pythons, knowledge is knowledge—regardless of where it’s collected or who deploys it. “There’s a lot of irony there,” Robert Reed, wildlife biologist and chief of USGS’s Invasive Species Science Branch, told me.
Knowing Burms’ preferred temperatures and humidity levels can help Florida researchers predict their spread or suggest locations for new breeding populations in Asia. A potentially deadly fungus holds the promise of a biological control agent—or forebodes a conservation obstacle. Discovering an efficient tracking method is useful whether you’re hoping to demonstrate population declines or rebounds. “I think of conservation and invasive species biology as two sides of the same coin,” Currylow told me. “It’s just context. It’s wherever you are in the world that dictates if an animal should be protected or eliminated.”
The Burmese python is one of many so-called invasive species—including carnivorous plants, sea lampreys, sheep, pine trees, rabbits, gargantuan fish, and softshell turtles, to name a few—to exist as both the endangered and the danger. In other words, they’re a species seen as worthy of conservation in one habitat and a threat to a native ecosystem in another. “Often it’s the study of invasions that drives our understanding of a species,” St. Mary’s College of California invasion ecologist Michael Marchetti of told me. “A lot of species are small or cryptic or hard to study, but once they become problematic they rise to the top.”
change redraws ecological boundaries and fuels mass extinction, paradoxical
invasives like the Burmese python could become more common, presenting
interesting philosophical and ethical questions for conservation biologists. If
harmony exists only in places untouched by humans, then is ecological discord simply
the new normal of a thoroughly disturbed planet? When the rules of entire
ecosystems are rewritten, does anything belong anywhere? The Burmese python,
both a villain and a victim, shows just how much we don’t know about our
“Venerable, sometimes conflicting, traditions shape our views of nature,” Cornell University herpetologist Harry Greene wrote in 1997. For many, Burmese pythons epitomize all the qualities—slithering, voracious, secretive, dangerous—humans despise in animals. For others, Burms and their paradoxical brethren symbolize the folly of labeling certain species as “invasive” and bad and others as “endangered” and good. “They’re a gateway drug to discarding the whole paradigm,” said science writer Emma Marris, an early advocate of conservation without ecological purism in her 2011 book, Rambunctious Garden: Saving Nature in a Post-Wild World.
Historians and sociologists in recent decades have accused invasion biology of inheriting and enshrining the nativism, racism, and xenophobia of late nineteenth- and early twentieth-century biologists and landscape architects, with terms like “aliens,” “exotics,” “outsiders,” and “invaders.” Within the field, there’s significant disagreement on basic tenets, like, for example, how long something has to be around to be “native.” Two hundred million years ago, with the continental drift? Thousands of years ago, when the first humans arrived in North America? Or several centuries ago, when European naturalists landed and documented what they saw? Is it “native” once other “native” species have adapted to eating it, perhaps? Sometimes that can happen rather quickly, and other times, biologists argue, it could take hundreds or even thousands of years for species to evolve to coexist with new arrivals.
A species’ mode of transportation, too, opens another sinkhole. How different are human-mediated introductions (like ship-hitchhiking quagga mussels, fire ants, and comb jellies) from “natural” arrivals (such as monitor lizards that surfed to new islands, sweet potatoes that some researchers think bobbed across oceans without human assistance, and spiders that traveled the world by wind)?
Arbitrary human sentimentality has also muddied the waters when it comes to policy. Not only do we despise non-native species that make us queasy or fearful, we’re less concerned about the origins of stuff we love: San Francisco’s parrots, Connecticut’s monk parakeets, the Bay Area’s eucalyptus trees, Italy’s tomatoes, Kentucky’s bluegrass, Jamaica’s cannabis, and even the West’s free-roaming wild horses. “Invasion biology is a science with many biases and constraints,” University of Tennessee ecologists wrote in 2013, “because species are never introduced from a random sample and they are not introduced to random places.”
Arguments over the distinction, if any, between what’s natural and what’s artificial are, of course, ancient. The ancient Greeks believed in a strict dichotomy between the two: Humanity is what people touch, and nature is everything else, “an alternative to—rather than a carrier of—human meanings,” as University of Chicago classics professor Mark Payne put it in 2014. But in 2020, few, if any, places remain free of our intervention. “The larger underlying question is, what is nature anyway, and does it matter?” University of Tennessee environmental scientist Daniel Simberloff told me.
Instead of bickering over labels, which he compares to “ rearranging the deck chairs on the Titanic,” Simberloff and many of his colleagues in ecology recommend dealing with a species’ immediate and local consequences. How is it reshaping its new home? Just because an introduced species is disappearing elsewhere doesn’t mean we should discount whether it’s tangling food webs, driving other creatures to extinction, harming human health, or costing us economically. Simberloff has described the Burmese python’s ecological damage as “staggering” in the Everglades—the country’s largest remaining subtropical wilderness, home to endangered and rare wildlife.
“It’s a system we’re trying to restore,” said Christina
Romagosa, a University of Florida ecologist
whose research has attempted to quantify the python’s trophic impact in
Florida. “It will eat just about anything that fits in its mouth, and we
don’t know what naturally controls their populations.” Those
facts lead Romagosa, like Simberloff,
to a more pragmatic perspective: “Do you need to study the plant or animal to death in order to take action? Should we just sit here and watch?” Meanwhile, she said, the snake is on the move, creeping north and west from Florida’s southern tip—an expansion enabled in more than one sense by humans.
Today, the Burmese python could live comfortably in America’s lower third. As the planet warms and more of the country becomes tropical, that range could expand, to wildlife officials’ chagrin—in part of a larger “reshuffling of species” already underway. But considering the species’ disappearance in Southeast Asia—a region facing its own dire climate impacts—North American invasion could fend off global extinction. “What a great insurance policy,” Marchetti told me.
Marris doesn’t care whether Burmese pythons are climate refugees or villainous invaders. “Ecology is the study of this very complicated and beautiful dance over millennia,” she said, “and in constant motion.” When we’re forced to witness that dynamism in real time, clinging to ecological purism only adds headache to heartbreak, Marris said. “It’s so fucking complicated out there, and that’s why it’s beautiful.”
Smith has observed this complexity firsthand. Since 2018, she has watched her serpentine subjects breed and multiply, tweezed ticks from their faces, and had them squeeze her hand until it turned almost purple. She even traced one’s tracker to a king cobra, which finished eating the smaller snake Smith had been tracking and slithered off, carrying the signal away with it. “That’s the thing, working with wild animals,” Smith told me. “They do whatever they want to.”