The Burmese python (Python bivittatus) is one of the five largest species of snakes in the world (about the third-largest as measured either by length or weight). It is native to a large area of tropical South and Southeast Asia. Until 2009, it was considered a subspecies of Python molurus, but now is recognized as belonging to a distinct species.
Burmese pythons are dark-colored snakes with many brown blotches bordered in black down the back. The perceived attractiveness of their skin pattern contributes to their popularity with both reptile keepers and the leather industry. The pattern is similar in colour, but different in actual pattern from the African rock python (Python sebae), sometimes resulting in confusion of the two species outside of their natural habitats. The African rock python can generally be distinguished by its tighter pattern of markings, compared to the Burmese python, which has bolder patterns, similar to those seen on a giraffe.
In the wild, Burmese pythons grow to 3.7 m (12 ft 2 in) on average, while specimens of more than 4 m (13 ft 1 in) are uncommon. This species is sexually dimorphic in size; females average only slightly longer, but are considerably heavier and bulkier than the males. For examples, length-weight comparisons in captive Burmese pythons for individual females have shown: at 3.47 m (11 ft 5 in) length, a specimen weighed 29 kg (64 lb), a specimen of just over 4 m (13 ft 1 in) weighed 36 kg (79 lb), a specimen of 4.5 m (14 ft 9 in) weighed 40 kg (88 lb), and a specimen of 5 m (16 ft 5 in) weighed 75 kg (165 lb). In comparison, length-weight comparisons for males found: a specimen of 2.8 m (9 ft 2 in) weighed 12 kg (26 lb), 2.97 m (9 ft 9 in) weighed 14.5 kg (32 lb), a specimen of 3 m (9 ft 10 in) weighed 7 kg (15 lb), and a specimen of 3.05 m (10 ft 0 in) weighed 18.5 kg (41 lb). In general, individuals over 5 m (16 ft 5 in) are rare. The record maximum length for Burmese pythons is held by a female named “Baby”, that lived at Serpent Safari, Gurnee, Illinois, for 27 years. Shortly after death, her actual length was determined to be 5.74 m (18 ft 10 in). Widely published data of specimens that were reported to have been even several feet longer are not verified. Dwarf forms occur on Java, Bali, and Sulawesi. On Bali, they reach an average length of 2 m (6 ft 7 in), and on Sulawesi, they achieve a maximum of 2.5 m (8.2 ft).
Distribution and habitat
Burmese pythons are found throughout Southern and Southeast Asia, including eastern India, Nepal, western Bhutan, southeastern Bangladesh, Myanmar, Thailand, Laos, Cambodia, Vietnam, northern continental Malaysia, far southern China (Fujian, Jiangxi, Guangdong, Hainan, Guangxi, and Yunnan), Hong Kong, and in Indonesia on Java, southern Sulawesi, Bali, and Sumbawa. Burmese pythons are also reported from Kinmen, very close to the Chinese mainland, but in Taiwanese territory; the Burmese python belongs to the fauna of Taiwan when Taiwan refers to the Republic of China, but not to the island of Taiwan.
These pythons are excellent swimmers and need a permanent source of water. They can be found in grasslands, marshes, swamps, rocky foothills, woodlands, river valleys, and jungles with open clearings. They are good climbers and have prehensile tails.
Python invasion has been particularly extensive, notably across South Florida, where a large number of pythons can now be found in the Florida Everglades. It has been suggested that the current number of Burmese pythons in the Florida everglades has reached a minimum viable population and become an invasive species. Hurricane Andrew in 1992 was deemed responsible for the destruction of a python breeding facility and zoo, and these escaped snakes spread and populated areas into the Everglades.  More than 1,330  have been captured in the Everglades. The importation of Burmese pythons was banned in the United States in January 2012 by the U.S. Department of the Interior.
A 2012 report stated, "in areas where the snakes are well established, foxes and rabbits have disappeared. Sightings of raccoons are down by 99.3%, opossums by 98.9%, and white-tailed deer by 94.1%." Bird and coyote populations may be threatened, as well as the already-rare Florida panther.
Spread and survival in the United States debate
By 2007, the Burmese python was found in northern Florida, and in the coastal areas of the Florida Panhandle. In February 2008, USGS scientists published a projected range map for the US, based on average climate data of the snake's home range and global warming projections, which predicted that by the end of the 21st century, these snakes could migrate to and flourish in as much as a third of the continental United States, including all three coasts.
However, a subsequent study produced a map incorporating both climatic extremes and averages which projected that the Burmese python's range as limited to southern Florida and extreme south Texas. Also, this projection was criticized in an unsigned Axcess News article as not having been peer-reviewed. Burmese pythons kept throughout winter in an experimental enclosure in South Carolina all died during the study, apparently because they could not properly acclimate to the cold, but most survived extended periods at temperatures below those typical of southern Florida. The report concluded, "Regarding areas of putative suitability and potential expansion within the United States, we find, remarkably, that the area in which the snakes are known to have colonized (south Florida) is essentially the only region where the climatic conditions are suitable for the pythons. Almost no potential for further continental expansion is predicted based on the results from the ecological niche models". 
Recently published data  contradict the initial USGS study  which claimed that non-native Burmese pythons could expand as far north as the southern third of the United States. The Burmese python will remain in the Everglades. Furthermore, other reputable herpetologists have commented on the controversial theory positing future migration past the Florida Everglades.
The National Geographic Society's resident herpetologist, Dr. Brady Barr, said, "Climate data reveal that temperatures found in southern Florida simply are not conducive to the long-term survival of large tropical snakes. When it gets cold, these snakes die." Dr. Barr also said "Feral hogs are a bigger problem for the Everglades than pythons. The press has sensationalized this story to the point that people think the sky is falling. Hopefully, comprehensive research such as Jacobson et al. will put an end to the hysteria."
Burmese pythons are mainly nocturnal rainforest dwellers. When young, they are equally at home on the ground and in trees, but as they gain girth, they tend to restrict most of their movements to the ground. They are also excellent swimmers, being able to stay submerged for up to half an hour. Burmese pythons spend the majority of their time hidden in the underbrush. In the northern parts of its range, the Indian python may brumate for some months during the cold season in a hollow tree, a hole in the riverbank, or under rocks. Brumation is biologically distinct from hibernation. While the behaviour has similar benefits, specifically to endure the winter without moving, it also involves preparation of both male and female reproductive organs for the upcoming breeding season. Controversy exists over whether the Burmese species is able to brumate.
Burmese pythons breed in the early spring, with females laying clutches of 12–36 eggs in March or April. They remain with the eggs until they hatch, wrapping around them and twitching their muscles in such a way as to raise the ambient temperature around the eggs by several degrees. Once the hatchlings use their egg tooth to cut their way out of their eggs, no further maternal care is given. The newly hatched often remain inside their eggs until they are ready to complete their first shedding of skin, after which they hunt for their first meal.
Like all snakes, the Burmese python is carnivorous. Its diet consists primarily of appropriately sized birds and mammals. The snake uses its sharp rearward-pointing teeth to seize its prey, then wraps its body around the prey, at the same time contracting its muscles, killing the prey by constriction. It is often found near human habitation due to the presence of rats, mice, and other vermin as a food source. However, its equal affinity for domesticated birds and mammals means it is often treated as a pest. In captivity, its diet consists primarily of commercially available, appropriately sized rats, graduating to larger prey such as rabbits and poultry as it grows. Exceptionally large pythons may even require larger food items such as pigs or goats, and are known to have attacked and eaten alligators and adult deer in Florida, where they are an invasive species.
The digestive response of Burmese pythons to such large prey has made them a model species for digestive physiology. A fasting python has a reduced stomach volume and acidity, reduced intestinal mass, and a 'normal' heart volume. After ingesting prey, the entire digestive system undergoes a massive remodelling, with rapid hypertrophy of the intestines, production of stomach acid, and a 40% increase in mass of the ventricle of the heart to fuel the digestive process.
Wild populations are considered to be "threatened" and are listed on Appendix II of CITES. All the giant pythons (including the Indian python, the African rock python, and the reticulated python) have historically been slaughtered to supply the world leather market, as well as for folk medicines, and captured for the pet trade. Some are also killed for food, particularly in China.
The IUCN has recently listed the Burmese python as "Vulnerable", reflecting its overall population decline. Important reasons for the decline are trade for skins and for food; habitat degradation may be a problem in some upland areas.
In Hong Kong, it is a protected species under Wild Animals Protection Ordinance Cap 170.
Burmese pythons are often sold as pets, and are made popular by their attractive colour and apparently easy-going nature. However, these animals have a rapid growth rate, and often exceed 2.1 m (6.9 ft) in length in a year if cared for and fed properly. By age four, they will have reached their adult size, though they continue growing very slowly throughout their lives, which may exceed 20 years.
Although this species has a reputation for docility, they are very powerful animals, capable of inflicting severe bites or even killing a keeper by constriction. They also consume large amounts of food, and due to their size, require large, often custom-built, secure enclosures. As a result, some are released into the wild, and become invasive species that devastate the environment. For this reason, some jurisdictions (including Florida due to the python invasion in the Everglades) have placed restrictions on the keeping of Burmese pythons as pets. Violators would be imprisoned for more than 7 years or fined $500,000 if convicted.
Burmese pythons are opportunistic feeders; they eat almost any time food is offered, and often act hungry even when they have recently eaten. As a result, they are often overfed, causing obesity-related problems to be common in captive Burmese pythons.
Although pythons are typically afraid of people due to their high stature, and generally avoid humans, special care is still required when handling them. Some jurisdictions require owners to hold special licenses, and as with any wild animal being kept in captivity, treating them with the respect an animal of this size commands is important.
The Burmese python is frequently captive-bred for colour, pattern, and more recently, size. Its albino form is especially popular and is the most widely available morph. They are white with patterns in butterscotch yellow and burnt orange. Also, "labyrinth" specimens with maze-like patterns, khaki-coloured "green", and "granite" with many small angular spots are available. Breeders have recently begun working with an island lineage of Burmese pythons. Early reports indicate that these "dwarf" Burmese have slightly different colouring and pattern from their mainland relatives and do not grow much over 2.1 m (6.9 ft) in length. One of the most sought-after of these variations is the leucistic Burmese. This particular variety is very rare, being entirely bright white with no pattern and blue eyes, and has only recently (2008/2009) been reproduced in captivity as the homozygous form (referred to as "super" by reptile keepers) of the codominant hypomelanistic trait. The caramel Burmese python has caramel-coloured pattern with "milk-chocolate" eyes.
- Burmese pythons in Florida
- Dwarf Burmese Python
- Exploding snake
- IBD, a viral disease affecting pythons
- Stuart, B.; Nguyen, T.Q.; Thy, N.; Grismer, L.; Chan-Ard, T.; Iskandar, D.; Golynsky, E. & Lau, M.W.N. (2012). "Python bivittatus". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 17 October 2012.
- Python bivittatus at the Reptarium.cz Reptile Database
- Jacobs, H.J.; Auliya, M.; Böhme, W. (2009). "On the taxonomy of the Burmese Python, Python molurus bivittatus KUHL, 1820, specifically on the Sulawesi population". Sauria. 31 (3): 5–11.
- Smith MA (1943). The Fauna of British India, Ceylon and Burma, Including the Whole of the Indo-Chinese Sub-region. Reptilia and Amphibia. Vol. III.—Serpentes. London: Secretary of State for India. (Taylor and Francis, printers). xii + 583 pp. (Python molurus bivittatus, pp. 108-109).
- Campden-Main SM (1970). A Field Guide to the Snakes of South Vietnam. Washington, District of Columbia. pp. 8-9.
- Barker DG, Barten SL, Ehrsam JP, Daddono L (2012). "The Corrected Lengths of Two Well-known Giant Pythons and the Establishment of a New Maximum Length Record for Burmese Pythons, Python bivittatus ". Bulletin of the Chicago Herpetological Society 47 (1): 1-6. pdf.
- Comparing Wild Florida Burmese & African Rock Pythons - https://www.youtube.com/watch?v=MosOA408Ye8
- Saint Girons H (1972). "Les serpents du Cambodge ". Mémoires du Muséum national d'Histoire naturelle, Série A 40-41. (in French).
- Deuve J (1970). "Serpents du Laos ". Mémoire O.R.S.T.O.M., Paris (39): 61-62, 65-66. (in French).
- Van Mierop, LHS; Barnard, SM (1976). "Observations on the reproduction of Python molurus bivittatus (Reptilia, Serpentes, Boidae)". Journal of Herpetology. 10: 333–340. doi:10.2307/1563071.
- Barker, DG; Murphy, JB; Smith, KW (1979). "Social behavior in a captive group of Indian pythons, Python molurus (Serpentes, Boidae) with formation of a linear social hierarchy". Copeia. 1979: 466–471. doi:10.2307/1443224.
- Marcellini, DL; Peters, A (1982). "Preliminary observations on endogeneous heat production after feeding in Python molurus". Journal of Herpetology. 16: 92–95. doi:10.2307/1563914.
- Jacobson, ER; Homer, B; Adams, W (1991). "Endocarditis and congestive heart failure in a Burmese python (Python molurus bivittatus)". Journal of Zoo and Wildlife Medicine. 22: 245–248.
- Groot, TVM; Bruins, E; Breeuwer, JAJ (2003). "Molecular genetic evidence for parthenogenesis in the Burmese python, Python molurus bivittatus". Heredity. 90 (2): 130–135. doi:10.1038/sj.hdy.6800210.
- McKay JL (2006). A Field Guide to the Amphibians and Reptiles of Bali. Krieger Publishing Company 2006. ISBN 1-57524-190-0. pp. 13, 14, 18, 86.
- de Lang R, Vogel G (2005). The Snakes of Sulawesi: A Field Guide to the Land Snakes of Sulawesi with Identification Keys. Frankfurt Contributions to Natural History Band 25, Edition Chimaira 2005. ISBN 3-930612-85-2. pp. 23-27, 198-201.
- Barker DG, Barker TM (2010). "The Distribution of the Burmese Python, Python bivittatus, in China" (PDF). Bulletin of the Chicago Herpetological Society. 45 (5): 86–88. The authors describe the presence of this specimen in Sichuan as an anomalous occurrence, and do not include the province in the python's range
- Barker DG, Barker TM (2008). "The Distribution of the Burmese Python, Python molurus bivittatus" (PDF). Bulletin of the Chicago Herpetological Society. 43 (3): 33–38.
- Breuer, Hans; Murphy, William Christopher (2009–2010). "Python molurus bivittatus". Snakes of Taiwan. Retrieved 17 October 2012.
- "Top 10 Invasive Species". Time. 2010-02-02. Retrieved 2010-04-27.
- "Democrats Hold Hearing on Administration’s Plan to Constrict Snakes in the Everglades - House Committee on Natural Resources". Naturalresources.house.gov. 2010-03-23. Retrieved 2012-08-09.
- http://www.nps.gov/ever/naturescience/burmesepython.htm (US National Park Service website - December 31, 2009)
- U.S. Fish and Wildlife Service. 2012. Salazar announces ban on importation and interstate transportation of four giant snakes that threaten Everglades. U.S. Fish and Wildlife Service Press Release. Jan 17 2012.
- Adams, Guy (2012-02-01). "Pythons are squeezing the life out of the Everglades, scientists warn". The Independent. London.
- U.S. Department of the Interior, U.S. Geological Survey (2008-02-20). USGS Maps Show Potential Non-Native Python Habitat Along Three U.S. Coasts. www.usgs.gov, last accessed 2008-03-11.
- Pyron, RA; Burbrink, FT; Guiher, TJ (2008). "Claims of Potential Expansion throughout the U.S. by Invasive Python Species Are Contradicted by Ecological Niche Models". PLoS ONE. 3 (8): e2931. doi:10.1371/journal.pone.0002931.
- , Axcess News (2012-03-12). U.S. Fish and Wildlife turn blind eye to science, fact. AXcess Business News, undated, last accessed 2017-02-09, previously accessed 2012-03-12 at a different URL.
- Dorcas, M. E.; Willson, J. D.; Gibbons, J. W. (2010). "Can invasive Burmese pythons inhabit temperate regions of the southeastern United States?". Biological Invasions. 13 (4): 793. doi:10.1007/s10530-010-9869-6.
- Jacobson; et al. (2012). "Environmental, physiology and behavior limit the range expansion of invasive Burmese pythons in southeastern USA". Integrative Zoology. 7: 271–85. PMID 22938524. doi:10.1111/j.1749-4877.2012.00306.x.
- (Reed Rodda 2008)
- Jacobson et al. (2012), Avery et al. 2010; Dorcas et al. 2011; Mazzotti et al. 2011
- Evans, Susan (2003). "Python molurus, Burmese Python". The deep Scaly Project. Digital Morphology. Retrieved 2007-07-25.
- Glossary of commonly used terms
- Ghosh, Anwiksha. "Burmese Python". AnimalSpot.net. Retrieved 27 December 2012.
- National Geographic: Python Bursts After Eating Gator
- "Large Python Captured, Killed After Devouring Adult Deer | KSEE 24 News - Central Valley's News Station: Fresno-Visalia - News, Sports, Weather | Local News". Ksee24.com. 2011-10-31. Retrieved 2012-08-09.
- "Digestive physiology of the Burmese python: broad regulation of integrated performance". Jeb.biologists.org. 2008-12-15. Retrieved 2012-08-09.
- Thirteen Foot Burmese Python Kills Owner
- Burrage, Gregg (2010-06-30). "New law makes Burmese python illegal in Florida". Abcactionnews.com. Retrieved 2012-08-09.
- Bryan Christy: The Lizard King: The True Crimes and Passions of the World's Greatest Reptile Smugglers. New York: TWELVE, 2008 ISBN 978-0-446-58095-3
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