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Anaconda Invasion?
The last thing the Everglades needs is another huge snake squeezing out native wildlife—but are green anacondas really breeding in the swamp?

Unless you’ve been hiding in a swamp for the last few years, you’ve probably heard that the Florida Everglades has a python problem. Up to 100,000 invasive Burmese pythons dwell in the ‘Glades, and the rapacious reptiles have been eating so much native fauna that last year the state of Florida held a python-hunting contest—albeit one that yielded more media coverage than actual serpents.

As if pythons weren’t enough, this week Slate spotlighted another snake scourge: green anacondas. “A breeding population of anacondas has been established” in the Everglades, Slate wrote, adding that because the South American behemoth is invulnerable to fire ants, it “could eventually prove to be the biggest problem in the United States’ wildest place.” The story, which alluded to “snakes large enough to swallow a man,” has been shared nearly 6,000 times on Facebook and picked up by media outlets, including OnEarth. (Here’s hoping someone tried to reach noted herpetologist Ice Cube for comment.)

But let’s examine the intelligence before we declare war against yet another invader. Have these huge, “unstoppable” snakes really become invasive in the ‘Glades? The scientists who study this stuff don’t really think so. According to the U.S. Geological Survey, only four anacondas have ever been confirmed in the whole state of Florida, and the USGS admits only the “possibility” of an established population. Four snakes in a decade might be a trend worth monitoring, but it’s miles from a verifiable invasion.

“There’s no real evidence that they’re reproducing,” says Michael Dorcas, a biologist at Davidson College who studies Burmese pythons. In the case of his specialty snakes, adds Dorcas, it took the discovery of babies and reproducing females to affirm that an “invasion” was under way. Anacondas just ain’t there yet.

David Steen, ecologist and author of the blog Living Alongside Wildlife, agrees. “Let me be clear: There is virtually no evidence that a population of anacondas exists in Florida,” Steen writes. He goes on to quote J.D. Wilson, the scientist who has literally written the book on invasive snakes, as stating, “We currently have no reason to suspect that anacondas are established in South Florida.” (Steen is also quick to note the irony that Jack Shealy, the man who captured the first Everglades anaconda a decade ago, is co-founder of the Skunk Ape Research Headquarters—an organization devoted to the pursuit of an apocryphal swamp creature.)

So what about the eyewitness accounts of snakes the size of hula hoops gliding through the wetlands? Well, while anacondas are certainly massive—an adult can reach anywhere from 20 to 30 feet long—Burmese pythons aren’t exactly midgets: one captured last spring measured nearly 19 feet. It’s not hard to imagine that all of those apparent anacondas are, in reality, just really big pythons.

And pythons are definitely a problem. One study has suggested that the snakes may be obliterating populations of mammals like raccoons and bobcats, and last year Smithsonian scientists determined that pythons are devouring birds and pilfering eggs. The pythons are a clear and present danger, while the anacondas are unverified. Fixating on the latest scare could lead us to concentrate our efforts on the wrong reptile.

Could there be anacondas breeding in the Everglades? Well, sure. After all, the park encompasses nearly 500,000 acres of wet wilderness—Elvis is farming alligators out there for all we know. The snake’s cryptic aquatic lifestyle also makes it well-equipped to avoid discovery. (According to Dorcas, however, Burmese pythons also spend “a heck of a lot of time” in the water and, like anacondas, are nearly impossible to detect—yet scientists haven’t had any trouble establishing that a python invasion is in progress. If anacondas were there en masse, they’d likely know.)

But just because there’s plenty of room for skepticism doesn’t mean we should ignore anaconda anecdotes. By not immediately responding to python reports back in 2000, the National Park Service may have lost its chance to control that crisis when it was still manageable. We shouldn’t disregard the possibility that anacondas are flourishing in the ‘Glades—but we shouldn’t take reports of invasion as gospel, either.

Besides, the Everglades faces graver concerns than invasive snakes. Sea level rise is making the park’s soil and groundwater more saline, and Florida’s water management regimes prioritize agriculture and flood control over ecosystem health. Although we’ve thankfully moved on from trying to drain the place, the River of Grass remains the only threatened World Heritage Site in the United States for a reason. And that reason isn’t anacondas.

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Ben Goldfarb is a freelance environmental writer whose work has appeared in The Guardian, Earth Island Journal, Green Futures Magazine, and elsewhere. He is a former editorial intern at OnEarth and former editor of Sage Magazine. MORE STORIES ➔