The reticulated python (Malayopython reticulatus) is a python species native to South and Southeast Asia. It is the world's longest snake, and the third heaviest after the green anaconda and Burmese python. It is listed as least concern on the IUCN Red List because of its wide distribution. In several countries in its range, it is hunted for its skin, for use in traditional medicine, and for sale as pets. Due to this, reticulated pythons are one of the most economically important reptiles worldwide. It is an excellent swimmer, has been reported far out at sea, and has colonized many small islands within its range. Like all pythons, it is a non-venomous constrictor. In very rare cases, adult humans have been killed (and in at least six reported cases, eaten) by reticulated pythons.

Taxonomy

The reticulated python was first described in 1801 by German naturalist Johann Gottlob Theaenus Schneider, who described two zoological specimens held by the Göttingen Museum in 1801 that differed slightly in colour and pattern as separate species—Boa reticulata and Boa rhombeata. The specific name, reticulatus, is Latin meaning "net-like", or reticulated, and is a reference to the complex color pattern. The generic name Python was proposed by French naturalist François Marie Daudin in 1803. American zoologist Arnold G. Kluge performed a cladistics analysis on morphological characters and recovered the reticulated python lineage as sister to the genus Python, hence not requiring a new generic name in 1993. In a 2004 genetics study using cytochrome b DNA, Robin Lawson and colleagues discovered the reticulated python as sister to Australo-Papuan pythons, rather than Python molurus and relatives. Raymond Hoser erected the genus Broghammerus for the reticulated python in 2004, naming it after German snake expert Stefan Broghammer, on the basis of dorsal patterns distinct from those of the genus Python, and a dark mid-dorsal line from the rear to the front of the head, and red or orange (rather than brown) iris colour. In 2008, Lesley H. Rawlings and colleagues reanalysed Kluge's morphological data and combined it with genetic material, finding the reticulated clade to be an offshoot of the Australo-Papuan lineage as well. They adopted and redefined the genus name Broghammerus. Most taxonomists choose to ignore Broghammerus and other names by Hoser as its description lacked scientific rigour and was not published in a reputable journal. R. Graham Reynolds and colleagues accordingly proposed the name Malayopython for this species and its sister species, the Timor python. Malayopython has been recognized by subsequent authors and the Reptile Database. Hoser has argued that Broghammerus was validly published and Malayopython name is invalid as it is a junior synonym. In 2021, the International Commission on Zoological Nomenclature found no basis for regarding the name Broghammerus to be invalid. Nevertheless, the name Malayopython remains in use by reliable sources.

Subspecies

Three subspecies have been proposed: The latter two are dwarf subspecies. Apparently, the population of the Sangihe Islands north of Sulawesi represents another such subspecies, which is basal to the P. r. reticulatus plus P. r. jampeanus clade, but it is not yet formally described. The proposed subspecies M. r. "dalegibbonsi", M. r. "euanedwardsi", M. r. "haydnmacphiei", M. r. "neilsonnemani", M. r. "patrickcouperi", and M. r. "stuartbigmorei" have not found general acceptance.

Characteristics

The reticulated python has smooth dorsal scales that are arranged in 69–79 rows at midbody. Deep pits occur on four anterior upper labials, on two or three anterior lower labials, and on five or six posterior lower labials. The reticulated python is the largest snake native to Asia. More than a thousand wild reticulated pythons in southern Sumatra were studied, and estimated to have a length range of 1.5 to 6.5 m, and a weight range of 1 to 75 kg. Reticulated pythons with lengths more than 6 m are rare, though according to the Guinness Book of World Records, it is the only extant snake to regularly exceed that length. One of the largest scientifically measured specimens, from Balikpapan, East Kalimantan, Indonesia, was measured under anesthesia at 6.95 m and weighed 59 kg after not having eaten for nearly 3 months. The specimen once widely accepted as the largest-ever "accurately" measured snake, that being Colossus, a specimen kept at the Highland Park Zoo (now the Pittsburgh Zoo and Aquarium) in Pittsburgh, Pennsylvania, during the 1950s and early 1960s, with a peak reported length of 8.7 m from a measurement in November 1956, was later shown to have been substantially shorter than previously reported. When Colossus died on 14 April 1963, its body was deposited in the Carnegie Museum of Natural History. At that time, its skeleton was measured and found to be 20 ft in total length, and the length of its fresh hide was measured as 23 ft. The hide tends to stretch from the skinning process, thus may be longer than the snake from which it came – e.g., by roughly 20–40% or more. The previous reports had been constructed by combining partial measurements with estimations to compensate for "kinks", since completely straightening an extremely large live python is virtually impossible. Because of these issues, a 2012 journal article concluded, "Colossus was neither the longest snake nor the heaviest snake ever maintained in captivity." Too large to be preserved with formaldehyde and then stored in alcohol, the specimen was instead prepared as a disarticulated skeleton. The hide was sent to a laboratory to be tanned, but it was either lost or destroyed, and now only the skull and selected vertebrae and ribs remain in the museum's collection. Considerable confusion exists in the literature over whether Colossus was male or female (females tend to be larger). Numerous reports have been made of larger snakes, but since none of these was measured by a scientist nor any of the specimens deposited at a museum, they must be regarded as unproven and possibly erroneous. In spite of what has been, for many years, a standing offer of a large financial reward (initially $1,000, later raised to $5,000, then $15,000 in 1978 and $50,000 in 1980) for a live, healthy snake 30 ft or longer by the New York Zoological Society (later renamed as the Wildlife Conservation Society), no attempt to claim this reward has ever been made.

Reported sizes

The colour pattern is a complex geometric pattern that incorporates different colours. The back typically has a series of irregular diamond shapes flanked by smaller markings with light centers. In this species' wide geographic range, much variation of size, colour, and markings commonly occurs. In zoo exhibits, the colour pattern may seem garish, but in a shadowy jungle environment amid fallen leaves and debris, it allows them to virtually disappear. Called disruptive colouration, it protects them from predators and helps them to catch their prey. The huge size and attractive pattern of this snake has made it a favorite zoo exhibit, with several individuals claimed to be above 20 ft in length and more than one claimed to be the largest in captivity. However, due to its huge size, immense strength, aggressive disposition, and the mobility of the skin relative to the body, it is very difficult to get exact length measurements of a living reticulated python, and weights are rarely indicative, as captive pythons are often obese. Claims made by zoos and animal parks are sometimes exaggerated, such as the claimed 14.85 m snake in Indonesia which was subsequently proven to be about 6.5 - 7 m long. For this reason, scientists do not accept the validity of length measurements unless performed on a dead or anesthetized snake that is later preserved in a museum collection or stored for scientific research. A reticulated python kept in the United States in Kansas City, Missouri, named "Medusa" is considered by the Guinness Book of World Records to be the longest living snake ever kept in captivity. In 2011 it was reported to measure 7.67 m and weigh 158.8 kg. In 2012, an albino reticulated python, named "Twinkie", housed in Fountain Valley, California, was considered to be the largest albino snake in captivity by the Guinness World Records. It measured 7 m in length and weighed about 168 kg. Dwarf forms of reticulated pythons also occur, from some islands northwest of Australia, and these are being selectively bred in captivity to be much smaller, resulting in animals often referred to as "super dwarfs". Adult super dwarf reticulated pythons are typically between 1.82 and 2.4 m in length.

Distribution and habitat

The reticulated python is found in South and Southeast Asia from the Nicobar Islands, India, Bangladesh, Myanmar, Thailand, Laos, Cambodia, Vietnam, Malaysia, and Singapore, east through Indonesia and the Indo-Australian Archipelago (Sumatra, the Mentawai Islands, the Natuna Islands, Borneo, Sulawesi, Java, Lombok, Sumbawa, Sumba, Flores, Timor, Maluku, Tanimbar Islands) and the Philippines (Basilan, Bohol, Cebu, Leyte, Luzon, Mindanao, Mindoro, Negros, Palawan, Panay, Polillo, Samar, Tawi-Tawi). The original description does not include a type locality. The type locality was restricted to "Java" by Brongersma (1972). Three subspecies have been proposed, but are not recognized in the Integrated Taxonomic Information System. The color and size can vary a great deal among the subspecies described. Geographical location is a good key to establishing the subspecies, as each one has a distinct geographical range. The reticulated python lives in rainforests, woodlands, and nearby grasslands. It is also associated with rivers and is found in areas with nearby streams and lakes. An excellent swimmer, it has even been reported far out at sea and has consequently colonized many small islands within its range. During the early years of the 20th century, it is said to have been common even in busy parts of Bangkok, sometimes eating domestic animals.

Behaviour and ecology

Diet

As with all pythons, the reticulated python is an ambush predator, usually waiting until prey wanders within strike range before seizing it in its coils and killing by constriction. Its natural diet includes mammals and occasionally birds. Small specimens up to 3 - 4 m long eat mainly small mammals such as rats, other rodents, mouse-eared bats, and treeshrews, whereas larger individuals switch to prey such as small Indian civet and binturong, primates, pigs, and deer weighing more than 60 kg. As a rule, the reticulated python seems able to swallow prey up to one-quarter its own length and up to its own weight. Near human habitation, it is known to snatch stray chickens, cats, and dogs on occasion. Among the largest documented prey items are a half-starved sun bear of 23 kg that was eaten by a 6.95 m specimen and took some 10 weeks to digest. At least one case is reported of a foraging python entering a forest hut and taking a child.

Reproduction

The reticulated python is oviparous. Adult females lay between 15 and 80 eggs per clutch. At an optimum incubation temperature of 31-32 C, the eggs take an average of 88 days to hatch. Hatchlings are at least 2 ft in length.

Danger to humans

The reticulated python is among the few snakes that prey on humans, and is the only species of snake where video and photographic proof exists of them having consumed humans. In 2015, the species was added to the Lacey Act of 1900, prohibiting import and interstate transport due to its "injurious" history with humans. Attacks on humans in captivity are not common. Wild pythons, however, are known to sometimes prey on humans, particularly in their natural habitat in Sulawesi, Indonesia. Considering the known maximum prey size, a full-grown reticulated python can open its jaws wide enough to swallow a human, but the width of the shoulders of some adult Homo sapiens can pose a problem for even a snake with sufficient size. Reports of human fatalities and human consumption (the latest examples of consumption of an adult human being well authenticated) include:

In captivity

Increased popularity of the reticulated python in the pet trade is due largely to increased efforts in captive breeding and selectively bred mutations such as the "albino" and "tiger" strains. Other notable color mutations recorded in this species include "sunfire", "motley", "Aztec", "ocelot", "rainbow", and "goldenchild". Some mutations, such as the "BEL" (black eyed leucistic) mutations are seldom bred due the discovery that they develop fatal gastrointestinal issues upon reaching adulthood. The "jaguar" color mutation is likewise controversial in the breeding of captive reticulated pythons, as certain specimens will develop neurological and osseous inner ears, similar to the "Spider" mutation that occurs in the ball python. It remains unclear as to why some individual pythons with the jaguar mutation display neurological issues associated with this genetic trait and others do not. Smaller animals such as the proposed "super dwarf" subspecies found on small islands are likewise popular due to their smaller size, as they grow to a fraction of the lengths and weights of their mainland kin due to genetics, limited space and prey availability. Dwarf and super dwarf reticulated pythons are likewise defined for captive animals as any reticulated pythons with at least 50 percent lineage hailing from seven select islands in the Selayer island chain near Sulawesi. It can make a good captive, but keepers working with adults from mainland populations should have previous experience with large constrictors to ensure safety to both animal and keeper. Although its interactivity and beauty draws much attention, some feel it is unpredictable. The python can bite and possibly constrict if it feels threatened, or mistakes a hand for food. While not venomous, large pythons can inflict serious injuries by biting, sometimes requiring stitches.