Florida’s invasive anacondas – Should we worry?

No. (Updated)
About 10 years ago, a Everglades native found and captured an unusual snake with his bare hands.

Green anacondas in the Everglades: The largest snake in the world has invaded the United States..

Trail Lakes Campground just happened to have a herpetologist on staff. Rick Scholle, who runs the campground’s roadside zoo, examined the snake and realized that he was looking at a juvenile green anaconda. A nonvenomous constrictor native to South America, the green anaconda is the biggest, heaviest species of snake in the world. It definitely does not belong in the Florida Everglades.

The article notes that much attention has been given to Burmese pythons as invasive species but this was possibly overblown. The python may be susceptible to fire ant attacks (one incident is related where a female snake was killed guarding her nest). The green anaconda gives birth to live young and is mostly aquatic. Many large snakes that could be large specimens have been reported but not substantiated.

Green anacondas haven’t gained much attention as an invasive species, but the state of Florida has become concerned enough about them that photos for identification were included in the study guide that I was assigned before participating in the “Python Challenge” hunting contest. Based on the specimens that people I’ve spoken to have collected, I am convinced that a breeding population of anacondas has become established. The questions are how many there are and how big they can really get.

Is this a scare piece or is a valid concern?

The green anaconda (Eunectes murinus) can get absolutely HUGE. It can reach 22 feet and larger sightings of up to 40 feet have been reported but not confirmed making it the second longest to the reticulated python but the heaviest. The green anaconda is native to the Amazon and Orinoco river areas of South America.

Occurrences in Florida:

In August 2004, a Green Anaconda (UF 143935) was collected from Big Cypress Swamp, Collier County, Florida. A juvenile male was collected in December 2004 from Fakahatchee Strand Preserve State Park in Collier County. An adult was capture in January 2010 at East Lake Fish Camp in Osceola County (Krysko et al. 2011). Another individual was collected in Osceola Park, Florida, in August 2010. More anecdotal reports exist for the Everglades area.

Anaconda captured in Florida park – Los Angeles Times.

Not many but they are there. There are no recorded deaths of humans and just a few attacks.

Here is an identification guide.

They are certainly here in Florida? Are they breeding? It’s not clear but that may be inevitable with time. Are they dangerous? Not particularly but that may also change with time depending on human interaction. It is a bit of a scare story. It was the top story on Slate. Effin’ big snakes in your backyard get attention.

Green anaconda (National Geographic)

Record-sized python caught in Florida with bare hands | Doubtful News.

Python hunt in Florida did not yield a big haul, but no person died | Doubtful News.

Addition: A good rebuttal of the Slate story: Living Alongside Wildlife: An Unstoppable Anaconda Invasion in Florida? What Slate Got Wrong..

The possibility of Green Anacondas secretly prowling and reproducing throughout the Everglades is a fun topic to discuss around the campfire. But, it doesn’t stand up to scientific scrutiny. I wish Slate had made that clear.

  5 comments for “Florida’s invasive anacondas – Should we worry?

  1. November 16, 2013 at 8:02 PM

    Wouldn’t the green anaconda be subject to the same ecological problems that the pythons have faced? Colder winter temperatures than this snake can typically handle should likely keep their numbers in check, and will certainly limit their size individually. Constrictors of this kind are not typically dangerous to humans until they cross a certain size boundary, making it more likely that their impact would be, as with the invasive pythons, on the survival of indigenous species of snake and prey animals only.

  2. Chris Howard
    November 16, 2013 at 8:38 PM

    Yeah, it seems like this would only be a problem in the southern most points of the Deep South, no?

  3. BobM
    November 16, 2013 at 9:27 PM

    Should we worry? As we live in New Zealand, probably not. Sorry couldn’t resist that. I did read somewhere however that it’s another invasive species, fire ants which is keeping the Burmese python in check. Largely because they stay in one place to protect their nests and eggs. Anacondas give birth to live young and don’t have to protect anything much :-).

  4. Lagaya1
    November 16, 2013 at 9:40 PM


  5. The_Village_Idiot
    November 18, 2013 at 7:22 AM

    They grow extremely slow to boot; they take about a decade to reach 10 feet and that’s only females. Males may never achieve such lengths in their lifetime. Slow growing also means slow breeding- something any invasive animal or pest requires. (Rats will be breeding within months; pythons can breed after about 2 years with males being known to breed at less than a year old. Anacondas can take 5 or more years to reach sexual maturity.)

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