Posts Tagged ‘burmese python’

indian rock python

I should note now that I really hate the way science journalism tends to overplay certain discoveries, and this week I saw a great example of “clickbait” science journalism run amok on what really is an interesting finding.

As long time readers know, I have been a bit obsessed with the successful colonization of Burmese pythons in South Florida. As someone who has lived his life in the true temperate zone of Eastern North America, which is usually called “humid continental” by some climate classification schemes, I have lived where most of the reptilian fauna are quite diminutive. The species that I will call a “black rat snake,” because of bizarre taxonomy boondoggle in which it is next to impossible to find a consensus on what one should properly call it, is the largest species of snake. The biggest specimens of that species can approach six feet in length. It’s an impressive snake for something in this cooler temperate zone, but it’s not a monster among squamates.

Florida, though, by a geographical accident, is a place where the lower parts of the peninsula have a climate much like Southeast Asia, and this area is connected to the 48 contiguous states.  This accident of geography means that Florida’s middle class had access to all the wonderful exotic pets that were popular throughout the country in the decades following the Second World War. The problem is that green iguanas and spectacled caimans cannot survive the winter in New Jersey or Michigan, but they can survive in Florida.

Burmese pythons became established in large swathes of South Florida around the year 2000. Lots of studies have gone into figuring out what the establishment of this large non-native constrictor could mean for biodiversity in Florida. A 2012 study concluded that massive declines in mammal diversity coincided with the establishment of the python in Everglades National Park. And a long-going debate still exists about how far north Burmese pythons will spread, a debate that started when the US geological survey released its analysis of how much of the southern US was actually quite good python habitat.

An experiment in which some Burmese pythons were kept outside year-round in South Carolina found the snakes just didn’t do well. The ten snakes died during a January cold snap, but the possibility exists that a more free range population could have found shelter in an armadillo burrow.

So maybe they won’t make it up through the South, but there has always been a catch in those studies. We assume that the Burmese pythons will remain pure, but various species of python do hybridize.  Burmese and African rock pythons do hybridize, and there are reasons to be concerned that a population of African rock pythons has also become established in parts of South Florida.  Many articles have been posted about the potential issues that could result if those two species hybridize, but thus far, no one has documented a hybrid of the two species in the wild.

But a study released a few days ago revealed that there was evidence that some of the feral Burmese pythons have mitochondrial DNA that can be traced to another species of python, the Indian rock python. It was the first study to do any kind of DNA analysis of the feral Burmese python population, and what it found was 13 Florida Burmese pythons out of the 426 sampled had Indian rock python mitochondrial DNA. The study did look at some nuclear DNA characters, and pretty much found that these odd ones still were overwhelming Burmese python in ancestry.

That is a quite small number, and the researchers were careful to point out that the hybridization event probably happened long before the pythons became established as invasive species.

I should note now that for most of my life, we regarded the Burmese python as a subspecies of the Indian rock python. Currently, there is a move to have the Burmese python raised to a full species status, but in the classical definition, the Burmese python was the subspecies of Indian rock python that evolved to live in humid and wetter places in Southeast Asia, while the Indian rock python proper lived in the more arid regions of South Asia.

The authors of the study that found the 13 pythons with Indian rock python mitochondrial DNA are using the paradigm of the Burmese python as a distinct species, so it does look like you have full species hybrid, even if it is just a mitochondrial DNA introgression.

This introgression could have happened in Asia, because it is not exactly clear how much hybridization happens in the wild where the ranges of the two species overlap. To make things even more interesting, the US Fish and Wildlife Service listed the Indian rock python as an endangered species through the ESA, and it was common for keepers of Indian rock pythons to cross them with captive Burmese pythons to avoid regulations on keeping and selling that species.

But the popular press’s understanding of what was discovered has been, well, not that nuanced.

Headlines, like The GuardiansSuper-snake: hybrid pythons could pose new threat to Florida Everglades” and Hello SWFL’sBurmese and Indian Pythons Breeding, Creating New Species,” lead one to think that this discovery is a sign that something really unusual has been discovered.

But the truth is that there is still a debate as to whether Burmese pythons represent a distinct species or not, and the authors have not found anything but some limited introgression of mitochondrial DNA from the Indian rock python in the feral Burmese population.

I should note that I do think that the Indian rock python and the Burmese python are distinct species, because the amount of genetic divergence between the two is pretty significant. However, they can hybridize and probably do so in the wild on a very limited basis. .

And it shouldn’t be a surprise that people would cross related species of exotic pets. Campbell’s and winter white dwarf hamsters have been crossed quite extensively, and hybrids with captive-reared felids are also quite well-known to the public.

Further, there are issues that we don’t know about the evolution of Burmese and Indian Rock pythons. We don’t know which genes each species has that allow them to be adapted to arid or wetter conditions. If we knew about these genetic differences, then we could test those hybrid snakes to see if they had inherited any other genes from the Indian rock python that would make it more easy for the snakes to colonize other areas.

We also don’t know how much Indian and Burmese pythons have been interbred in captivity or in the wild.  It very well could be that having some captive Burmese with this Indian rock python mitochondrial DNA is actually pretty representative of the pet population.

But we don’t have that information yet.  What we do have is the discovery of this mitochondrial DNA in the Burmese population, and that’s a pretty amazing discovery.

But it is not sign of a new hybrid species of super python. I will gladly eat my hat if more evidence is discovered, but I think we have a good case of the press blowing a really interesting discovery totally out of proportion.

Which does happen, especially during the silly season of late August and early September.





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Jake and Ivy are python-hunting Labrador retrievers.

Mark Derr sent me this link about some python tracking dogs in the Everglades:

The scenario sounds like a low-budget movie from the 1970s: humongous snakes are on the loose, eating everything in sight. But this is real – a problem that an American university and its canines are helping to combat.

Auburn researchers used detection dogs in the Everglades National Park to find Burmese pythons during a recent study on ways to manage and eradicate these non-native, invasive snakes, which are eating native wildlife, mostly mammals and birds.

‘The ultimate use for detection dogs is to suppress the expanding python population and to eliminate them in small areas, such as on an island. Our main concern is their impact on other wildlife,’ said Christina Romagosa of Auburn’s School of Forestry and Wildlife Sciences.

‘Interraction with humans is also a problem. The snakes, like alligators, can get in swimming pools, eat small dogs and cats, and could injure a human.’

Auburn worked last year with the Everglades Cooperative Invasive Species Management Area, or ECISMA, to test how well dogs could pinpoint the snakes’ locations so wildlife agencies could remove the snakes.

The problem started years ago, and was probably a result of irresponsible python owners.


Jake and Ivy, both black Labrador retrievers, helped the researchers capture 19 pythons, most between six and eight feet in length, including a pregnant one with 19 viable eggs. Burmese pythons in their native range in South East Asia have been known to reach up to 20 feet and weigh almost 200lb. The National Park Service has counted 1,825 Burmese pythons that have been caught in and around Everglades National Park since 2000.

‘We found the use of detection dogs to be a valuable addition to the current tools used to manage and control pythons,’ said Romagosa. ‘Dog search teams can cover more distance and can have higher accuracy rates in particular scenarios than human searchers. We suggest that dogs be used as a complement to current search and trapping methods.’

The Auburn study found that dogs and their sense of smell were two-and-a-half times faster than people visually searching, but people did have the advantage in extreme humidity. Searches by detection dogs are ideal in the cooler months, Romagosa says, when dogs can work longer periods of time without overheating. [A huge problem with any double-coated dog, especially a black one.]

‘Dogs can also be used throughout the year as part of a rapid response team going to a python sighting, which can be helpful in an urban as well as natural environment,’ she said.

The dogs are trained to ‘alert’, or sit down, when they got within five meters of a python.

‘When the dogs alerted to a python’s presence in the field, we would put them in the truck so they would not come in contact with it,’ trainer Bart Rogers said. ‘The dogs could even track pythons that had been present in the area hours earlier. They did not pay attention to ‘gators and other snakes, which would also avoid the dogs.’

Interestingly, the Labrador retrievers, which love to get wet, had to be trained not to go into the water.

‘They love the water but in the training we reward them for staying out of it,’ added Rogers. ‘We could train them to find pythons in water, but we are limited in that we couldn’t easily capture pythons if they are under water.’

The snakes found by the dogs have been sent to Skip Snow, a National Park Service biologist at the Everglades National Park. Some snakes were euthanized, some were tagged with radio telemetry devices for further study and tracking, and some were donated to the Nature Conservancy for use in training personnel how to catch snakes.

A driven retriever can be trained to find just about anything.

When I was a kid, my grandpa lost his wallet deer hunting.

My dad took one our dogs out and got her to fetch a wallet a few times.

Then he got my grandpa to throw the wallet a few times.

They went to the woods where my grandpa had been hunting, and she found the wallet, which had several hundred dollars in it, in less than 20 minutes.

If they can find wallets, they can find snakes!





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From Orange News:

Nearly 1,000 people flocked to a wedding in Cambodia – between two snakes.

Bride Chamreun, a 16ft python weighing 200lb, wed her smaller mate in Village One in Kandal province, just south of the capital Phnom Penh.

Buddhist monks blessed the pair and villagers showered them with flowers during the two-hour ceremony believed to bring prosperity and peace to those attending.

“We organised the wedding ceremony for the pythons in order to oust bad things and bring good luck and happiness for our villages,” said 41-year-old Neth Vy, who owns Chamreun.

“We were told that the two pythons are husband and wife and they need to live together, and if we don’t marry them we will meet bad luck.”

Mr Neth said he had found the then-tiny python while fishing in 1994, and that she had become part of the family.

Since taking the snake in, he said no misfortune had befallen his family.

The python groom, named Krong Pich, was caught 12 days ago by people in a neighbouring village.

Apparently, it’s bad luck to let your pythons live in sin.




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This python is a Borneo bateater.

What? You made that up!

No. That’s the trade name for a hybrid between the very common Burmese python and the reticulated python. It is a pretty good trade name.

The discovery of a feral population of African rock pythons in South Florida has caused some concerns among the conservation community. Florida is home to a well-established population of Burmese pythons, and it is feared that they could hybridize with the African rock pythons and make a “super snake.”

Of course, African rock pythons aren’t that common here. However, they can handle a more varied climate than the Burmese python can. The Burmese python is a subspecies of the Indian or Asian rock python. The other subspecies is the nominate Indian python subspecies, and the two subspecies are truly separated. Burmese pythons need more humid climates, while Indian pythons prefer more arid conditions. (To make things less confusing, this blog will call the Indian python the subspecies found in the arid regions of the Subcontinent, even though both subspecies are often called Indian pythons.)

African rock pythons have an even broader range than the Indian python. Their range includes virtually all of Sub-Saharan Africa south to South Africa and Namibia. The original southern terminus of the range was KwaZulu-Natal, which actually has a very temperate climate. That means that it is more cold tolerant than the Burmese python, which makes it only as far north as the tropical/subtropical transition region of China.

And if there were more African rock pythons in captivity in this country, I would be would be more concerned.

But there may be lots of limiting factors that would prevent them from taking over the subtropical parts of the US.

In fact, I think that I was wrong to think that the Burmese pythons would take over the US. Long-time readers of this blog, might remember this post where I linked to the US Geological Survey’s forecast for Burmese python range expansion.  I was accepting of the findings, but then I read this study. It seems that South Florida is about the only place where Burmese pythons could live in the wild in the US.  And even if we accept that climate change models as being valid, climate change actually reduces the suitable habitat for the Burms.

So claims that Burmese pythons are going to colonize New Jersey are probably not accurate.

However, I have yet to see any analysis on the potential range of the African rock python or a potential African rock python/Burmese hybrid. Maybe they could be better adapted to colonizing the US.


Now, the Borneo bateater isn’t a hybrid between the Burmese python and the African rock python. It is a hybrid between the Burmese and reticulated python. It is possible that the retics could colonize South Florida, and they are much more common in the US pet trade than African rock python.

And in case you didn’t know, the retics are the longest species of snake, approaching nearly 30 feet in length.

Pet retics have killed their owners, as have several Burmese pythons.

That’s why owning one requires a certain level of caution and a great deal of knowledge.

These animals deserve more than to be treated as curiosities and symbols of machismo. They need enlightened owners who can provide them with what they need.

I do not oppose python ownership, but I really wish more was done to ensure that these animals were in the right hands.

And I say this from this perspective: I’ve always thought these animals were cool, but I don’t know enough about caring for them to really provide the right home for one. I think feeding them full-sized rabbits would get expensive after a while.

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It’s not a bad B-Movie:


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It’s not a bad B-Movie:



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