That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

The Burmese or Asian Rock Python, Python molurus bivittatus (or Python bivittatus, see below) is one the world’s longest snakes, and vies with the Green Anaconda for the title of heaviest. Florida’s introduced Burmese Pythons are often in the news these days for causing ecological havoc and occasional human fatalities.  However, not much attention is given to this massive serpent’s life in its natural habitat.

Description

Matched in size only by the Reticulated Python and Green Anaconda (the heaviest of which I’ve encountered tipped the scales at 215 lbs.), this stoutly-built snake may reach 25 feet in length, although animals of 18-20 feet are considered large.

“Baby”, a huge female in residence at Illinois’ Serpent Safari Park, is said to measure 27 feet in length and weigh 403 pounds (please check out this video).  A specimen under my care at the Bronx Zoo exceeded 300 pounds in weight and consumed 30-40 pound pigs with little difficulty.  The large albino python has been on exhibit at the Brooklyn Children’s Museum for over 20 years.

The ground color is yellowish-buff or tan fading to cream along the flanks, with large chestnut-brown blotches throughout.  There is an arrow-shaped mark on top of the head.  A variety of color morphs are common in the pet trade.

Most taxonomists now classify this snake as a distinct species, rather than as a subspecies of the Indian Python.

Range

The Burmese Python ranges widely throughout South and Southeast Asia, including northeastern India, Myanmar, southern Nepal, Thailand, Laos, Cambodia, Vietnam and southern China (including Hainan and Hong Kong).  Introduced populations are established in Florida and Puerto Rico.  Records from Sumatra and Borneo are likely misidentifications.

The closely-related Indian Python, Python molurus, is found in India, Pakistan, Sri Lanka and Nepal.

Habitat

This snake is extremely adaptable, but requires the presence of a permanent water source.  It inhabits wooded grasslands, swamps, open forests, river valleys and rocky foothills.  Farms, suburbs and the fringes of urban areas are frequently colonized.

Natural Diet

All pythons have thermo-receptive sensory pits along the upper jaw that assist in locating warm-blooded animals at night.  Prey is killed by constriction, with death resulting due to compression of the lungs and heart failure (via pressure on the heart and blood vessels).

The range of animals taken is vast.  Adults usually concentrate on monkeys, deer (Muntjac, Chital, Hog Deer, Sambar Fawns) wild pigs, Peafowl, Red Jungle Fowl, small cats and other carnivores, and large rodents.  Toads, fishes, porcupines, pangolins and monitor lizards are listed as prey in several older field reports.

In his classic book The Giant Snakes (a “must read” for all snake fans!), Clifford Pope reports that a Leopard measuring 4’ 2” long was taken by an 18 foot Burmese Python and that a young captive consumed 61 pounds of rats in one year, thereby adding 34.5 pounds to her weight.  The largest meal of which I’m personally aware is a 50 pound pig taken by a captive in theUSA.

Humans and Domestic Animals as Prey

Burmese Pythons, Reticulated Pythons, Green Anacondas and African Rock Pythons are the only constrictors known to have killed people.  The reported cases concerning Burmese Pythons involved large pets attacking their owners; in several cases, escapees have attempted to consume children.  The other species mentioned have, on rare occasions, preyed upon people in natural (free-living) situations.

In addition to such tragic encounters, pythons also run afoul of people by feeding upon domestic animals.  I was once called to Prospect Park, Brooklyn to deal with an escaped pet snake that had consumed a cat (much to the horror of a large crowd of onlookers!).  Some years ago, an article in Herpetological Review recounted the story of a python that ate 2 chickens on a farm in China.  Upon capture, the snake regurgitated the chickens, which were promptly carted off by their rightful owner.  Domestic geese, ducks, goats, sheep, pigs and dogs are also taken on farms and in suburban areas.

Burmese Pythons in Florida are known to take endangered species such as Key Largo Wood Rats.  One now famous photo taken in the Everglades depicts a massive individual trying to swallow a large alligator.  In Puerto Rico, it is feared that introduced Burmese Pythons will out-compete and prey upon the endangered Puerto Rican Boa.

Please see my article Giant Snake Meals http://blogs.thatpetplace.com/thatreptileblog/2008/04/11/big-snake-meals/ for some personal and recorded observations on this topic (130 pound Impala, Siamese cat belonging to king of former Siam, etc.)

Status

Despite its wide range and adaptability, the Burmese Python is threatened in some regions by habitat loss and by over-collection for the leather and traditional medicine trades. Huge numbers were collected for sale as pets in years past, but most are now captive-born.

Burmese Pythons are bred in Vietnam for release as rodent control agents, but are killed for preying on domestic animals in other countries.  The species is listed on Appendix II of CITES and protected by the government ofIndia.

Longevity

Captives have lived for over 34 years; unknown in the wild.

Reproduction

Pythons possess a pair of vestigial legs (“spurs”) alongside the cloaca.  These are larger in males, and are rubbed along the female’s body during courtship.  Mating occurs from January through March, during periods of slightly reduced temperature.

In common with all pythons, the female protects and incubates her eggs.  Females engage in a “shivering” motion that can raise their own core temperatures and that of the egg clutch.

Female Burmese Pythons lay 18-100 eggs after a gestation period of 60-150 days.  The eggs hatch in 55-75 days.  The hatchlings are 18-24 inches long (large enough to consume adult mice) and become sexually mature at a length of approximately 10 feet (males) to 13 feet (females).  Under captive conditions, sexual maturity can be attained in 3 years.

 

 

Further Reading

Giant Snake Meals

Video: capture of huge python in Florida

The Giant Snakes (Clifford Pope, 1965); don’t miss this classic!

The Green Anaconda: Natural History of the World’s Largest Snake

Range information for all Pythons (40 species)

 

Burmese Python image referenced from wikipedia and originally posted by Mariluna
Albino Burmese Python image referenced from wikipedia and originally posted by Mike Murphy

This is the first in a new series of what I’ll call “Myth-Buster Articles”, which will focus on beliefs or practices that have aroused debate in the herpetological community.  After reviewing the available research and my own and others experiences, I will attempt to sort fact from fiction.  Today I’ll highlight the recent studies that have sought to determine if introduced Burmese Pythons, Python molurus bivittatus (a.k.a. P. b. bivittatus) may eventually spread north and west from their current strongholds in South Florida.  Links to the articles mentioned are included below.

Studies comparing the climate in the USA with that in the Burmese Python’s native range (South and Southeast Asia), including one by the US Geological Survey, have predicted that the huge snakes may eventually range north to Delaware and southern Maryland  and west to California.  In all, 32 states were said to provide possible habitat. Read More »

In 2008, a computer-based study by the US Geological Survey stated that Florida’s introduced Burmese Pythons (Python molurus bivittatus) might colonize up to 1/3 of the United States in time.  While the snakes’ presence in Florida is a severe problem, the release of this study generated a flood of illogical fears and predictions.  Recently, another study conducted by a noted herpetologist and utilizing live snakes has injected some sanity into the controversy. Read More »

Like most reptile keepers, I have often marveled at the efficiency of snake digestive systems.  I attributed their abilities to break down bone to “powerful digestive enzymes”, but recent research has shown that, at least for Burmese Pythons (Python molurus), a far more complex and amazing process is at work.

Digesting Large Vertebrates

I’ve observed some quite large snake feasts – a Red Foot Tortoise and a 60 pound deer taken by Green Anacondas (the tortoise was an unfortunate exhibit mate; the deer fell to an anaconda at my study site in Venezuela) and 40 pound pigs regularly fed to Reticulated and Burmese Pythons under my care at the Bronx Zoo, for example.

A few shell scutes, hoofs, some bone fragments and fur where all that passed in the feces of these snakes – the rest being digested.  How do they do it?

Bone-Digesting Cells

Research at the Louis Pasteur and Indiana Universities has revealed that, after feeding, the digestive systems of Burmese Pythons undergo a dramatic transformation.  New cells are produced and worn-out cells die and are eliminated in preparation for the work at hand.

Studies of the small intestine have uncovered a new type of cell, previously unknown to science.  These cells are responsible for degrading bone and releasing its components into the snake’s bloodstream.  This process promotes efficient calcium absorption, and may be the reason that most captive snakes do not require a UVB source if fed a diet comprised of whole rats, mice and other vertebrates.

Warm-Blooded Snakes?  Not Quite, but…

We’ve known for some time now that Burmese Pythons break the “cold-blooded” rule when digesting their meals.  While most snakes must seek out a hot basking spot in order to maximize digestion, Burmese Pythons can actually raise their internal temperatures without an external heat source! 

Further Reading

Please see Big Snake Meals for some examples of how large (and unusual) snake prey can be.

To read about recent research concerning another unusual snake feeding adaptation, please see How Snakes Grow despite Food Deprivation.

An account of the original research showing that pythons can raise their body temperatures may be found in this Journal of Herpetology article.

 

A general principle of reptile-keeping holds that “several small meals are better than one”, but there is no denying the fascination aroused by the swallowing abilities of the giant constricting snakes. I myself, even after decades of working with large snakes in zoos, was stunned when a 17 foot long anaconda I helped to capture in Venezuela disgorged a deer weighing 60 pounds (this at 3AM, below the hammock upon which I was trying to sleep)! I also observed anacondas swallowing a large side-necked turtle, Podocnemis unifilis, a 5 foot long spectacled caiman, Caiman crocodilus and a 10 pound red-footed tortoise, Geochelone carbonaria. Keepers at the Singapore Zoo informed me that a free-ranging reticulated python consumed a 40 pound cape hunting dog exhibited there.

Perhaps the most startling account is given by the Carl Hagenbeck of the Hamburg Zoo – a 25 foot long reticulated python in his collection consumed a 71 pound ibex (wild goat) several days after eating two goats of 28 and 39 pounds, for a total of 138 pounds of food within a few days! The largest meal reliably documented to have been taken by any snake seems to be the 130 pound impala eaten by an African rock python, P. sebae in South Africa(recorded by W. Rose, 1955). The group’s most “elegant” meal must surely be a Siamese cat (including bells and collar) that was taken by a reticulated python that wandered into the palace of a former king of Thailand!

Reticulated pythons are, along with anacondas, Burmese pythons, P. molurus, and African rock pythons, the only snakes known to have consumed people. I have had, unfortunately, first-hand experience with a feeding-accident fatality in NYC. Obviously, giant snake ownership is not to be undertaken lightly.

I would be very happy to learn of your own observations of snakes large and small, and to entertain your questions. Thanks.

An engrossing overview of giant snake behavior is given by famous herpetologist Clifford Pope in The Giant Snakes, 1961, A. Knopf, NY. You can also find further information at:
http://www.reptileknowledge.com/