'Holy smokes ... This is science fact': What scientists have learned fighting Burmese pythons

It’s an old plot line: As a place’s inhabitants innocently go about their business, aliens land.

Unbeknownst to the natives, the invaders stealthily disperse, quickly eating every living thing in their path on their way to total domination. But wait! A small cell of warriors is hard at work in the background, learning everything they can about the intruders. The final battle pits human smarts against relentlessly multiplying cold-blooded muscle. Who will win? Stay tuned …

Swap Burmese pythons for the aliens, make the Everglades the location, pick a plucky band of scientists for the warriors and you’ve got the grim cliffhanger unfolding before our eyes.

“It’s like, holy smokes,” says wildlife biologist Ian Bartoszek, a leader of the Conservancy of Southwest Florida’s anti-python corps. “I don’t think we could have come up with something like this that’s not science fiction. But this is science fact.”

The conflict was seeded half a century ago, though whether by escaped pets, reptile dealer dumping or hurricane-freed zoo specimens is open for debate.

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Since then, python numbers have mushroomed, as they've eaten their way through Florida's beloved RIver of Grass. The stakes are so high it sometimes seems scientists are throwing everything they can at the problem to see what sticks: drones, sniffer dogs and ‒ the Conservancy's specialty ‒ transmitter-implanted scout snakes. Every bit of knowledge gained helps. Included in Florida's annual budget passed last month is $3.35 million to rid the state of pythons and other exotic nuisances and "research and to assess risk and the efficacy of control efforts, and for the development and implementation of innovative technologies."

Focusing on an area south of Alligator Alley in the western Everglades, the Conservancy so far has pulled from the 160-square mile wilderness lab more than 1,000 snakes and about 10,000 eggs, totaling more than 30,000 pounds of dead weight. But don’t look for python steaks any time soon. Everglades apex predators tend to concentrate environmental mercury in their tissues, and many parasites prey on the predators, making them a risky meal (though not un-heard of – the now-closed Evan’s in Fort Myers served Everglades pizzas featuring frog legs, gator and filleted python).

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'We jump on big snakes ... then we're on to the next one'

Over the years, Bartoszek has seen some things – "And some things I can't unsee," he says, like the full-grown white-tail deer digesting inside a snake – more than once. Or the time he came across seven pythons in a single gopher tortoise burrow.

Then there was the Colossus of Picayune Strand, an 18-foot-long female tipping the scales at an astonishing 215 pounds, laden with 122 eggs, a testament to the fecundity of these invasive giants.

More: Caught! Record-breaking 18-foot Burmese python pulled from Collier County wilderness

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Though he's sympathetic to the hard-wired human fear response to snakes, he's long since tamped it down where pythons are concerned. "We actually had to un-program that with the snake team," he says. "We understand what we do is not the norm. We jump on big snakes, catch them and put them in bags and then we’re on to the next one (and) this isn’t just a snake – this is a giant snake."

There are things in the world that are worth fearing, he says, but "It’s hands-down more dangerous to drive in Southwest Florida during season than it is to handle a pile of pythons."

Where have all the rabbits gone?

What is truly scary: what these snakes have done to Florida's natural systems.

So dramatic their destruction – and so clearly humans' fault (they didn't travel to Florida on their own) – Burmese pythons were used as a major plot point in novelist T.C. Boyle's recent "Blue Skies," a catastrophist romp through coast-to-coast climate disaster, with a Florida Burmese python as a plot hinge.

In one scene, a biologist character raves, "These things ... They’ve decimated the Everglades, hunted down every last thing that walks or crawls or flies ... From muskrats to raccoons and egrets ‒ and deer, even deer, for Christ’s sake . . . Alligators! They’re eating their way through the alligators now.”

Though Boyle and others use the word "decimated" to describe the pythons' effect on wildlife, it's too mild a word. It means to reduce by one tenth. But in the Everglades, pythons have effectively removed whole categories of animal. Anecdotal reports have floated around for years that there are few to no small mammals left in the 'Glades, but could that really be true?

Yes, indeed, says Jacquelyn Guzy, the U.S. Geological Survey population ecologist and lead author of "Burmese pythons in Florida: A synthesis of biology, impacts, and management tools," a book-length scholarly review of python science in Florida released earlier this year.

Years in the making, the paper's intent was to "consolidate and interpret what we know from the science to inform knowledge gaps and start to describe what information could be useful for research going forward," says Guzy. One of the extraordinary things about the review: "There were 37 of us from across federal and state agencies, academic universities, and non-profit institutions all helping to shape this document, which is peer-reviewed and freely available online." Getting dozens of academics to agree on anything can be like herding, well, snakes, so to produce a work that represents the consensus of the scientific community on the invasion is a rare thing indeed, she says.

Once teeming with mammals, the park is now all but bereft of small, furry critters. Raccoons have plummeted by a staggering 99.3%, while opossums and bobcats have suffered losses of 98.9% and 87.5%, respectively. Marsh rabbits, cottontail rabbits, and foxes have become spectral.

It started around 2003, Guzy says, and pythons were formally flagged as the culprit in 2012. "Since then, observational and experimental studies have confirmed pythons are responsible for these declines. We know from necropsy data that as many as 76 different species have been found in python gastrointestinal tracts and while small mammals such as rats are most numerous, birds make up the most diversity." But they eat large creatures like bobcats and deer plus "a wide variety of highly mobile bird species," she says, which means pretty much any native warm-blood is vulnerable. And just because no one has documented panther predation doesn't mean it hasn't happened, scientists say.

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What do such dramatic drops mean for the natural system as a whole?

"The Burmese python has caused a rearrangement and simplification of the mammal community that has begun to alter other ecosystem processes," Guzy says, noting that such changes are often intricate and hard to study and predict. For example, "We expect the loss of marsh rabbits and similar species will likely alter (feeding) interactions and ecosystem function within the Everglades because marsh rabbits likely functioned as a keystone species through their important roles as primary consumers, seed dispersers, and prey for a variety of predators."

In other words, without the rabbits, things start falling apart.

More: Deadly Burmese pythons: Summer means it's time for biologists to crank out necropsies

"Other indirect effects from Burmese pythons include the spread of pathogens and parasites to native species as well as alteration of host-parasite dynamics," Guzy says.

In an unnerving chain of cause-and-effect, scientists found the snakes' eating habits are creating ecosystem gaps then exploited by other species. An article published earlier this month in Live Science details the problem: "Burmese pythons are helping rats take over Florida's Everglades — and that could help spread disease."

The challenges are enormous and scientists like Guzy are clear-eyed about the end game. "Thus far eradication of pythons in southern Florida seems impossible, but we may be able to locally suppress the population in certain areas," she says. How many there are is anyone's guess, but scientists are loath to guess. Some facts may help illuminate the big picture. Since 2000, more than 17,000 wild Burmese pythons have been removed from the state of Florida, wrote Florida Fish and Wildlife Conservation Commission spokeswoman Carli Segelson.

Guzy puts it bluntly: "Population size estimates are some of the most important missing pieces as far as successful suppression the Burmese python invasion. We all want these estimates because they provide a benchmark to know if control or suppression efforts are working in an area. So far, there are no reliable python population estimates for any area."

So far, there's been no concerted effort to exterminate them wholesale, "even in limited areas," Guzy said, "because of the difficulty detecting them."

"Difficulty" is putting it mildly. Masters of mystery, pythons melt into the landscape with ease. "These snakes are extremely cryptic and secretive, and they are inherently difficult to find," Guzy says. Making things harder is that they inhabit "vast wilderness areas of southern Florida, an area with few roads, that is largely inaccessible to most people."

Not only does that make developing control tools tough, it effectively prevents population estimates, she says. Without population estimates, there aren't benchmarks to measure what's working.

Snakes in the water, snakes on the move

Strong swimmers, Burmese pythons can stay submerged up to half an hour and some have made it to the Keys.

Pythons are tropical snakes and cold is a potentially limiting factor, but just how limiting remains to be seen, natural selection being what it is.

“Alva, LaBelle, they’re knocking at your door,” Bartoszek says. “And the day you stop seeing roadkill ‘possum and start seeing roadkill pythons, it’s too late.

Once upon a time, he says, it was widely believed that this side (south) of S.R. 29 is as far north as they go. The highway runs from the ‘Glades up to Palmdale in Glades County. Not any more, he says, and some researchers are finding them north of Lake Okeechobee.

Evolution in action has also answered a question some have asked: Why can't we just gather them all up and ship them back to Asia where they came from? After all, in their home range, they're on the International Union of Conservation Naturalists' red list, which documents species at risk of extinction.

Because it's too late, Bartoszek says; Florida pythons are no longer the same creatures. "The snakes here have evolved to the point that they have different DNA from the snakes in their home range, which is one reason why the snakes can't be sent back to Southeast Asia."

Sounding the alarm without being too sensational is a delicate balance. On one hand, the situation is legitimately dire, Bartoszek says, and it wouldn’t be wrong to call the Everglades invasion our ‘Silent Spring’ moment (after Rachel Carson’s book of the same name, which warned of the catastrophic effects of pesticides on wildlife – especially birds – and sparked increased environmental awareness.)

"I don’t want to come off all melodramatic, but I’m telling you this is a serious threat to our native wildlife,” he says, emphasis on wildlife and not humans, “They’re not coming for you,” he says, “and they’re not coming for your kids. (We) need to be cool, calm and follow the science (and) we need to brainstorm a wider strategy for the bioregion.”

How will future control efforts look?

Though the South Florida Water Management District runs a popular annual python hunt complete with wide media coverage and cash prizes, Bartoszek sees that as more awareness tool than strategy. “You can get the Florida man effect and it complicates things.”

So far, no one removal method looks more promising than others. “Each has its limitations, and so the more tools we have at our disposal, the better,” Guzy says.

Maybe future approaches will include gene editing or maybe python birth control could be developed. Both are on the table.

“Genetic biocontrol tools represent exciting possibilities that are actively being explored,” Guzy says. “For example, potential goals include changes to the genome that could result in generational shifts in sex ratios or promote infertility that could help induce population collapse.” (Similar approaches have been tried with mosquitoes in the Keys.) “However, these tools are still a long way from being used," she says.

After a decade of going all-out at this problem, Bartoszek is more than open to help. "If somebody comes in our lab tomorrow and shows us a better way to get after these animals – not just running up a kill count on a bunch of hatchlings in the summertime and declaring victory – we would change up what we’re doing tomorrow,” he says. “I’d buy them a pitcher of beer and we’d share notes and I think it’d be awesome.

"But to date, we kind of feel like we’ve been in this battle for a decade, really trying to defend the goal over here and we need people to get off the sidelines and get into this fray.”

This article originally appeared on Naples Daily News: Burmese Pythons: Real-time battles with snake swallowing Everglades