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Creature Feature: Burmese Pythons Prowl the Everglades, and That’s Not a Good Thing

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A wildlife drama plays out as a gator tangles with a big Burmese python in Everglades National Park. NPS photo by Lori Oberhofer.

Breeding populations of Burmese pythons have been established in extensive areas of Florida. In vulnerable places like Everglades National Park, limiting the growth and spread of this ecologically disruptive and potentially dangerous invader will be a very daunting task.

The Burmese python (Python molurus bivittatus) is a large constrictor native to the rain forests of Southeast Asia. Because it’s got attractively patterned skin, has a generally docile disposition, and is fairly inexpensive to purchase (about $70), it’s been imported in fairly large numbers here in the United States. It is thought that there are at least 5,000 pet pythons in Florida alone.

Pythons can be difficult to manage in captivity, especially if they are large and poorly kept. Over the years, many of these pet pythons have escaped or been intentionally released into the wild by owners who no longer want them.

Breeding populations have been established in the wild in Everglades National Park and are thought to exists in various other parts of Florida as well. Florida's warm climate is similar to the one that this rain forest species was designed by nature to inhabit.

We don’t want Burmese pythons living wild and free in America. We don’t want them loose in places where they can get at our pets. We don’t want them lurking near our children. We don’t want them living in our national parks and competing with the native predators for food and space.

However, unless we do something to prevent it, it’s only a matter of time before all of these things will be true in at least one-third of the 48-state U.S. They are already true in parts of Florida, including Everglades National Park.

There is a good reason to be concerned about Burmese pythons living in the wild here in America.

The Burmese python is an impressive animal, and that is an understatement by several orders of magnitude. The Burmese python is the world’s sixth-biggest snake species. A python continues to grow all of its life, and it’s not unusual for a fully mature Burmese to weigh 150 pounds and stretch 16 to 18 feet in length. The largest ones on record are much bigger than that.

A captive Burmese python living at the Serpent Safari Park in Gurnee, Illinois, is the largest living snake on record. Tagged with the unlikely name “Baby,” this enormous reptile is 27 feet long and weighs just over 400 pounds. (If you’ve got a tape measure that will reach all the way out to 27 feet, run it out there and see if that doesn’t make you glad that damn thing isn’t on the loose!)

The Burmese python is not just fast growing and long-lived (typically 20 years or so in the wild), it’s also an efficient predator. And as they get bigger these snakes gain the ability to take down and eat ever larger animals. A good-sized python can kill a water bird, a piglet, a fawn, a raccoon, a bobcat, a dog, a child. A whopper is as big around as a telephone pole and can kill and eat a pig, a goat, a deer, a good-sized alligator, a man.

Pythons kill by constriction. In practical terms, this means that they bite their victim and hang on with their sharp, backward-facing teeth while they coil their powerful bodies around the animal and squeeze it until it dies from suffocation.

It’s a bad way to go. Every time the victim exhales, the snake takes up the slack, preventing the intake of a full breath. There is no escape.

The size of the prey that pythons manage to swallow is a constant source of amazement. The secret is in the amazingly stretchy ligaments in the python’s jaws. A python’s jaws aren’t hinged in the manner of human jaws. The python’s jaws just spread further and further apart as the teeth work the victim further and further back. No chewing necessary; the victim is just swallowed whole.

This thing is on the loose in America. Although breeding populations are thought to exist only in Florida at this time, the Burmese python is capable of surviving and reproducing in about one-third of the 48-state U.S. The southern tier of states from Florida to east Texas are in the bullseye right now, and a warming climate, coupled with the species’ already proven adaptability, portends an even larger potential range.

Wildlife biologists are working on a strategy to slow and perhaps reverse the spread of this invasive species, but it’s an uphill task. There are lots of things this snake does that makes it difficult to deal with.

For example, young pythons spend most of their time in trees. Have you ever tried to spot pythons up there in the branches? On the ground the darn thing blends in so well with its surroundings that it can be extremely difficult to spot from only a few feet away. That’s disconcerting. The Burmese is also an excellent swimmer and can cross water bodies of substantial size. Did you know that a python can remain submerged for as long as half an hour?

And boy, are they ever prolific. Females lay clutches of 30-50 or more eggs and guard them for several months. Only a small fraction of the young snakes survive to adulthood, but that’s still a lot of snakes.

The NPS has been dealing with pythons in Everglades National Park for quite a while, and the pace is picking up. The first one, a road-kill on U.S. 41, was discovered 30 years ago, and by the 1990s about a dozen a year were being found. The first baby python was discovered in 1995. The first clutches of python eggs and already hatched nestlings were discovered around three years ago. Python sightings in the park now run to about 250 a year.

Much publicity attended the October 2005 discovery of a 13-foot python in the park that had swallowed a six-foot long alligator. Swollen and sluggish during the digesting of this hefty meal, the python was killed and partially eaten by another gator.

No one knows how many pythons there are in the park at the moment. Some estimates based on presumed densities run into the thousands, but that's little more than a guess.

We’ll have more to say about pythons in Everglades National Park and measures being developed to control them. It's an interesting story in itself.

Postscript: Is an anaconda invasion on the way too? One of these big water loving snakes has been discovered already in Big Cypress National Preserve.

Traveler trivia, no extra charge: About 60 million years ago, a snake of nightmare proportions prowled the tropical forests of northern South America. Dubbed Titanoboa cerrejonensis by paleontologists, this 42-footer (imagine that!) dined on crocodiles and other large prey. It’s still the largest snake species ever discovered.

Comments

Bruce, please explain to me what discipline of science you studied and at what university?  You clearly have no idea what you are talking about.  Tilting the balance of nature --for the economy or for the love of having a giant useless reptile as a caged pet-- is only going to lead to trouble in the long run.  Think of Rome, Or the Maya.  Maybe in your supremely enlightened view, it's not a big deal --for apperently no other reason than that it has happened-- but several thousand years of recorded human history would stand against you.  Read a book.


Hello all,
       I just want erverone to think The Native American have had to deal with an invasive species of human beings (Us) that did untold amouts of damage to the Americas ecosystem, and are still doing it today. I do not see what is going on in florida any diffrent. Everyone of you can say what you want to. The truth is the Burmese (American) Python is less invasive on the enviroment than we will ever be. I do not see them as an Invasive species anymore That snake believe it or not has already adapted to living there. This snake is actually listed as prtected in several asian country right now. So lets think about this.... we kill them here and they are dying there this equals no Burmese Python. This is an amazing animal That also needs to be preserved, As it is one of the oldest living animals on earth. This is considered to be a prehistoric snake. i personally have a Burmese Python, and I would not want to see this beautiful animal be wiped off the planet because of a presived imbalance. Let not forget that thy do live with the other oldest predator on the planet. The american Alligator. we need to keep our noses out of it and everything will rebalance itself.


Not a whole lot of kudzu in the Everglades, Jon.

I am a biologist (at least the paper on the wall in my mom's den says so), but the answer to the question of how many large pythons can live in the Everglades is mostly simple math.

Roughly 2000 km^2 between Everglades NP and Big Cypress, plus another 3000 km^2 or so in the water management areas, so roughly 5000 km^2 area: there's a lot of swamp out there.

Pythons, like most snakes, are not territorial in terms of staying within and defending a territory; they tend to wander from place to place. Also, pythons, like most constrictors and vipers, eat so infrequently (~once every 1-3 months) that they resorb the villi on their intestinal linings between meals because the metabolic cost of maintaining them exceeds the cost of regenerating them every month or so (google Secor Diamond snake digestive physiology; they even have a couple papers on Burmese pythons). [ok, so there is some biology in my answer.]

The net primary production in the Everglades varies spatially from 20 - 18000 grams per square meter per year. Picking 1000g/m^2/yr, each km^2 fixes ~10^6kg per year. Allowing a relatively low ecological efficiency of .1-1%, that's still 1000-10000kg/km^2/yr of prey.

So, at 4-8 prey per year at 50-80kg per prey, the greater Everglades could easily support 3 to at least 5 (perhaps more) large adult pythons per km^2 at equilibrium, or 15000-25000 large adults. ["Easily" does not mean that there would not be substantial negative effects, only that if alligators and other predators get out-competed, python populations could conceivably grow until reaching numbers in that ballpark.]

I don't know the current best estimates of adult python numbers, and I suspect that there still aren't good estimates based on actual sampling data. My best guess would be somewhere between 500 and 2000 large individuals, where I get to change the cutoff for large (6' plus or minus a couple of feet) to whatever is necessary to make my numbers right.

In contrast, panthers are territorial, actively defend their territories (one of the top causes of mortality of dispersing juvenile panthers), need to eat every few days, and eat a much narrower range of prey. My understanding is that the greater Everglades probably couldn't support a population of even 100 panthers under current conditions.


Do they eat kudzu?


I am not a biologist. Last night I saw a program on channel 13 about these Burmese pythons. I want somebody to explain to me, or correct me, how The Everyglades can support an evergrowing popoulation of these cretures, or of any top of the food chain animal. I was always taught that the larger a predator, the larger a terrutory it needs to live in, feed, and breed. In otherwords, these giant creatures need a much larger area in which to live than, proprortionally, than, say, a shrew. So it seems to me, The Everyglades CANNOT SUPPORT a population of thousands of giant snakes. It is ecologically impossible. Somebody do the math for me.


From what I've read on the INET, the python is here to stay. The fact that it is a large constrictor and dangerous in certain situations doesn't lessen the fact we will have to learn to live with it. I suspect our own growth, urban sprawl and habitat destruction will restrict their range much as it has for most of our wild life.


Anyone who has ever been in contact with Burmese Pythons knows that there are gentle giants, and much less likely to injure humans than most dogs are; everything else is media frenzy.
I have worked a lot with Burmese pythons and used them in may educational events during which kids of all ages play with them. Yes, respect them, like any other animal. But don't fall for the image hollywood and animal planet have painted.

Btw, the original report by the USGS about the Florida problem with Burmese pythons has long been dismissed by scientific review. On the topic, Dave & Tracy Barker have provided several reviews of the issue on:

http://www.vpi.com/publications

Besides, just consider this: Literally millions of boas and pythons are kept as pets in the US, and have been kept since at least 3 decades. No wild populations of any pythons or boas have ever been reported, except for the souther 3 counties of Florida. It is therefore simply a FACT that they are not invasive, except for southern Florida (and btw, pythons in Florida have also been reported over more than a decade). This is therefore state local problem that needs a state local solution. No other location in the US will ever be affected.


Don’t forget the Indigo Snakes, Kingsnakes, Storks, Hawks, Gar, Large Mouth Bass, Soft-shell Turtles, Raccoons, Opossum, and Feral Pigs that would also love to make a meal out of these snakes.
Personally I am all for the capture of these snakes instead of the Ban they are trying to put upon these beautiful animals. If they would pay me I would go down there and spend day in and day out to capture these animals so this ban doesn’t go through. I own many Boa Constrictors and a few other varieties of snakes and I love them all to death. I have never had a problem with them that wasn’t my fault. I hope someone finds a logical way to stop the Burms. The Python Ban is not a logical answer to the problem at hand.
I agree with Nate, we shouldn’t try to scare the public because there are unfortunate accidents like that. Besides there is no proof that a Burm or any other large constrictor has ever actually eaten a person. But in the cases of the children who were killed by the snakes it was human error, to even thinking you could keep such a large animal in an improper cage without consequences is absolutely insane.


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