Papuan carpet python (Morelia spilota harrisoni) – StarPythons

Buying a Papuan Carpet Python: Everything You Need to Know

The Papuan carpet python is the only member of the Morelia spilota complex found outside Australia – a compact, richly patterned snake confined to two isolated pockets of tropical savanna along the southern coast of New Guinea. Known in herpetoculture as the "IJ carpet python" or simply "Irian Jaya," this subspecies has been a staple of the international reptile hobby for decades, with most animals in the trade originating from the Merauke region of Indonesian Papua. At StarPythons, we have been working with Papuan carpet pythons since 2007, including outstanding lineages such as the original Piet Nuyten Granite line. On this page, you will find everything you need to know before buying one: from species biology and natural history to terrarium setup, feeding, breeding, and what to look for when choosing your animal. Our guide draws on firsthand breeding experience as well as the field research of Daniel Natusch, Jessica Lyons, and Mark O'Shea – among the very few scientists who have studied these snakes in their remote New Guinea habitat.

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Quick Facts: Papuan Carpet Pythons at a Glance

Feature Details
Scientific Name Morelia spilota harrisoni
Other Common Names IJ carpet python, Irian Jaya carpet python, New Guinea carpet python
Size 1.5–2.0 m (4.9–6.6 ft) average
Life Expectancy 20-30 Years
Cage Size 120 × 70 × 80 cm / 4 × 2.3 × 2.6 ft (L × W × H)
Temperature Summer (Daytime) 27–28 °C (80–82 °F), Hotspot 35–38 °C (95–100 °F)
Temperature Winter (Daytime) 25–27 °C (77–80 °F), Hotspot 31–34 °C (88–93 °F)
Feeding Interval Every 14-21 days
Winter Rest Mild cooling recommended
Suitable for Beginners Yes – manageable size and generally robust
Distribution Southern New Guinea (Indonesian Papua and Papua New Guinea)

Introduction

The Papuan carpet python (Morelia spilota harrisoni) occupies a unique position in the carpet python complex: it is the only population found outside the Australian continent. Confined to pockets of dry tropical savanna along the southern coast of New Guinea – on both the Indonesian and Papua New Guinean sides of the island – it represents a relict population left behind when rising sea levels severed the land bridge that once connected Australia and New Guinea at the end of the Pleistocene.

In the hobby, these snakes are most commonly known as "IJ" or "Irian Jaya" carpet pythons, a name that refers to the former Indonesian name for the western half of the island. The label has stuck, even though it is historically imprecise: carpet pythons occur on both sides of the international border, and the name "Irian Jaya" itself was only in official use between 1973 and 2002. For clarity, we use the common name "Papuan carpet python" and the subspecific designation M. s. harrisoni on this page, consistent with the traditional nomenclature used throughout herpetoculture and in CITES documentation. The reasoning behind our taxonomic position is outlined in the Taxonomy section below and discussed in more detail on our Darwin carpet python page.

What defines the Papuan carpet python in captivity is a combination of moderate size, striking ontogenetic colour change, and a characterful – at times feisty – temperament. Neonates hatch in shades of rust-red, gradually transitioning to the warm browns, tans, and orange lateral flames of the adult pattern. They are also the foundation of one of the most sought-after recessive morphs in the complex: the Granite carpet python.

Table of Contents

Taxonomy and Nomenclature

The taxonomic history of the Papuan carpet python is closely intertwined with that of the Darwin carpet python. For much of the twentieth century, the New Guinea populations were classified either as part of a broadly defined M. s. variegata or simply left unresolved. In 2000, Raymond Hoser formally described the New Guinea population as Morelia harrisoni sp. nov., based on three specimens in the American Museum of Natural History, New York (holotype: AMNH 82433, a female from Port Moresby, PNG). The taxon was named after David Harrison, who died in 1999. Hoser described the animal at full species rank, but the broader herpetological community – including Mense (2004, 2006, 2009) – has consistently treated it as a subspecies within the Morelia spilota complex, using the combination M. s. harrisoni. It should be noted that Hoser's taxonomic work is contested among professional herpetologists; Kaiser et al. (2013) have formally argued against recognising several of Hoser's nomenclatural acts, and some authors do not accept harrisoni as a valid taxon at all. In herpetoculture and CITES trade documentation, however, the name M. s. harrisoni has gained widespread and practical acceptance.

Recent molecular work has complicated this picture. Genetic analyses by Ciavaglia et al. (2015) demonstrated that the carpet pythons of New Guinea are very closely related to populations on the Cape York Peninsula in northern Queensland and to the Darwin carpet pythons of the Northern Territory and Kimberley. Phylogenomic work by Esquerré et al. (2020), using 376 nuclear loci, confirmed that the Morelia spilota complex diversified rapidly and recently – so recently that even large-scale genomic data struggles to resolve the relationships between subspecies cleanly. This shallow genetic divergence is exactly what one would expect for populations that were connected by continuous habitat on the Sahul Shelf until a few thousand years ago. Mutton and Julander (2022) subsequently elected to synonymise all three regional forms under a single designation, M. s. variegata, treating them as populations within a single clade rather than as distinct subspecies. Their reasoning is biogeographic: during the last glacial maximum approximately 20,000 years ago, sea levels were around 120 metres lower than today, exposing the Sahul Shelf and creating continuous land connections between New Guinea and Australia. As sea levels rose during the terminal Pleistocene, the populations were progressively isolated. The final separation – the formation of the Torres Strait between the Cape York Peninsula and New Guinea – occurred just 5,800–9,000 years ago (Mutton & Julander, 2022), which is extremely recent in evolutionary terms.

Despite this close genetic relationship, we continue to use the designation M. s. harrisoni for the New Guinea population on this page. Our reasoning is pragmatic rather than taxonomic: harrisoni remains the name used throughout herpetoculture and in established breeding records worldwide; it is the designation under which these animals are documented in CITES trade permits; and it provides practical clarity when discussing lineage purity and breeding programmes. We recognise that the phylogenetic evidence supports a very close relationship between all three regional forms and will revise our designations as scientific consensus develops.

For a detailed discussion of the variegata complex and the biogeographic history of the Sahul Shelf, see our Darwin carpet python page.

Distribution, Habitat and Lifestyle

Range

The Papuan carpet python is known from two seemingly disjunct populations along the southern coast of New Guinea, both confined to areas south of latitude 7°S. In total, 281 locality records have been compiled for the species across New Guinea (Natusch & Lyons, 2012). The western population – and the one best known to the reptile trade – resides in a relatively small area stretching from the western edge of the Merauke Regency in Papua Province, Indonesia, southeast along the coast and across the international border into the southwest corner of Western Province, Papua New Guinea. The city of Merauke serves as the main collection and export hub for carpet pythons entering the international pet trade (Natusch & Lyons, 2012).

A second, smaller population occupies roughly 174 km of coastline within the Central Province of Papua New Guinea. Records span from Yule Island in the north, through the Port Moresby area, south to Kemabola, and inland as far as the Sogeri Plateau (O'Shea, 1996). Approximately 350 km of open ocean separates this eastern population from the Merauke group, and the relationship between the two has not been studied in detail (Mutton & Julander, 2022).

Notably, carpet pythons do not appear to be present on Yos Sudarso, a large island at the western edge of their range, despite the presence of seemingly suitable habitat. Reports of carpet pythons north of the Central Cordillera – the mountain spine that runs the length of New Guinea – remain unsubstantiated; a single specimen reportedly collected along the Mamberamo River in 1920 is most likely a recording error, and no further specimens have been found on the northern side of the island (Mutton & Julander, 2022).

Habitat

Papuan carpet pythons are found in areas of tropical savanna and eucalypt woodland – dry, grassy environments that are atypical of the lush image most people associate with New Guinea. These isolated pockets of savanna contain vast seasonal wetlands and support a rich and diverse fauna, but they are bordered by rainforest, which appears to act as a barrier to dispersal. Traders and villagers confirmed that carpet pythons were found close to the coast in tropical woodlands and were absent further inland where rainforest vegetation dominates (Natusch & Lyons, 2012). The habitat preference closely mirrors that of their closest Australian relatives in the Top End – both populations are savanna specialists, not rainforest inhabitants.

Lifestyle

In contrast to the strongly arboreal Darwin carpet python, which spends around 70 % of its time above ground, Papuan carpet pythons appear to be primarily ground-dwelling. They utilise tree hollows, burrows, and other secure areas as refuge sites (O'Shea, 1996), but are not characterised by the committed arboreality of their Australian counterparts. In the relatively stable tropical climate of southern New Guinea, these snakes are predominantly nocturnal and increase their activity during or just after heavy rain – a welcome event in the seasonally dry savanna they inhabit (Mense, 2006).

Published ecological data on wild New Guinea carpet pythons remain scarce. The terrain across their range is remote, often difficult to access, and in some areas hazardous to work in. Road infrastructure is minimal, which has made systematic field surveys all but impossible (Mutton & Julander, 2022). The majority of published observations come from a small number of herpetologists who have worked in the region, most notably Mark O'Shea and Daniel Natusch.

One aspect of their natural history that has clear implications for the trade: these pythons are frequently killed by local inhabitants when encountered. O'Shea reports observing approximately 15 carpet pythons that had been killed by locals during a single visit to the Port Moresby area – a number that, paradoxically, suggests stable populations in the region while also highlighting the pressures these animals face (Mutton & Julander, 2022). Despite this persecution, Papuan carpet pythons appear to adapt well to human-disturbed environments, a trait shared with carpet pythons across the entire complex.

Size, Appearance and Variation

Size

The Papuan carpet python is often perceived as one of the smaller forms of Morelia spilota, but adult sizes are only marginally smaller than those of most other subspecies. Based on a sample of 174 individuals measured from the Indonesian trade, females averaged 179 cm SVL and 1,608 g, while males averaged 140 cm SVL and 916 g (Natusch & Lyons, 2012) – though this average is skewed by the inclusion of subadult males in the sample. When only the largest 20 % of individuals are compared, the size difference narrows considerably: males measured 192 cm and 2,042 g, females 202 cm and 2,203 g (Natusch & Lyons, 2012).

The largest individual recorded in the field was a male measuring 222 cm (7 ft 3 in) SVL with a mass of 3,189 g – a substantial animal by any standard. One exceptionally large wild-collected female, imported at 1.8 m, attained a length of 2.6 m (8.5 ft) after three years in captivity and deposited a clutch of 33 eggs (Mutton, pers. obs., as cited in Mutton & Julander, 2022).

There may be regional variation in body build: O'Shea (2007) reports that large specimens from Western Province, PNG, are more stoutly built than animals from the easternmost population in Central Province.

Males reach sexual maturity at around 92 cm SVL, while the smallest mature female recorded measured 147 cm SVL (Natusch & Lyons, 2012).

Appearance

The overall impression of an adult Papuan carpet python is that of a moderately proportioned, banded snake. The head is broad and set off clearly from the neck; the tail is long and strongly prehensile, as in all Morelia. In cross-section, the body is close to cylindrical – there is little of the lateral compression seen in more arboreal species. The pattern is variable but typically consists of irregular crossbands, sometimes interrupted by a jagged dorsal stripe. Fully striped animals occur as well. The labial scales carry bold dark markings, and the head pattern tends to be well-defined and persistent into adulthood (Mutton & Julander, 2022; Mense, 2009).

Adults are predominantly brown – from deep chocolate to light olive – with the dorsal surface always darker than the flanks. Lighter pattern elements range from tan to pale grey and are edged by dark-pigmented scales. Compared to some other members of the complex, the overall variation in colour and pattern is relatively restrained (Mutton & Julander, 2022).

Ontogenetic Colour Change

Like their close relative the Darwin carpet python, Papuan carpet pythons undergo a dramatic ontogenetic colour change – one of the most visually striking developmental transformations in the complex. Hatchlings are predominantly rust-red with very little dark pigmentation; the pale pattern elements at this stage are subtle, ranging from tan to pinkish with barely visible borders. Over the first months of life, melanin production increases progressively and the warm reds give way to deepening shades of brown, beginning on the dorsal surface and spreading laterally. At the same time, the pale crossband elements gain contrast as their borders darken, and the overall appearance shifts from a soft, monochromatic juvenile to a crisply banded subadult. A characteristic – and transient – feature of this transition is that the dark lateral markings may take on purple or lavender tones before maturing into the final orange-brown of the adult pattern (Mutton & Julander, 2022). Most animals have lost their juvenile colouration within the first year, though the full transition to adult colours can take up to two years (Mense, 2009).

Enclosure, Temperatures and Feeding

Cage Size

For an adult Papuan carpet python, we recommend a minimum enclosure size of 120 × 70 × 80 cm (4 × 2.3 × 2.6 ft, L × W × H). Although these snakes are less arboreal than their Darwin relatives, they will readily use climbing opportunities and are often found high up in their enclosures (Mense, 2009) – vertical space should not be neglected. Juveniles can be started in smaller setups and graduated to larger enclosures as they grow.

Climbing and Hiding

While Papuan carpet pythons are primarily ground-dwelling in the wild, captive animals benefit from a combination of sturdy climbing branches and secure ground-level hides. Provide at least one hide in the warm zone and one in the cool zone – both should be snug enough for the snake to feel its body in contact with the walls. Cork bark tubes, hollow logs, and stacked platforms all work well. The key is offering the animal a choice between terrestrial and elevated resting positions.

Temperatures

Papuan carpet pythons come from a tropical monsoon climate with minimal temperature variation across the year. Seasonal cycling in captivity should reflect a modest dry-season cooling rather than the dramatic drops appropriate for diamond or coastal carpet pythons.

Summer (Wet Season)

Daytime 27–28 °C (80–82 °F)
Spot / Heating Mat 35–38 °C (95–100 °F)
Nighttime 23–25 °C (73–77 °F)
Humidity 65 % rH

Winter (Dry Season)

Daytime 25–27 °C (77–80 °F)
Spot / Heating Mat 31–34 °C (88–93 °F)
Nighttime 20–23 °C (68–73 °F)
Humidity 65 % rH

Important: As with all members of the Morelia spilota complex, a basking hotspot is critical. After feeding, carpet pythons seek out temperatures significantly warmer than their normal preferred range to initiate digestion – a well-documented thermophilic response. A hotspot that is always available allows the animal to self-regulate this process. Without it, digestion slows, and the risk of regurgitation increases.

Feeding

For adult Papuan carpet pythons, offer an appropriately sized rodent every 14 to 21 days. Juveniles should be fed more frequently, approximately every 7 to 10 days. As with all carpet pythons, feed according to body condition rather than a rigid calendar. Mense (2009) reports that hatchlings can be challenging first feeders, accepting only relatively large, already furred and fast-moving mice – however, this has not been our experience at StarPythons, where our captive-bred hatchlings accept thawed frozen prey from forceps without difficulty.

One behavioural trait worth noting: Papuan carpet pythons can show greater sensitivity to changes in their enclosure than other subspecies – rearranging furniture or moving the animal to a new terrarium may trigger food refusal lasting several weeks. This sensitivity is most pronounced in animals under three years of age and generally diminishes with maturity (Mense, 2009). Their feeding response itself, however, is intense: these are ambush predators that will strike at anything moving when the enclosure is opened at night.

In the wild, Papuan carpet pythons feed exclusively on mammals based on available data. Three larger individuals (140–174 cm SVL) had eaten bandicoots (family Peramelidae), while the smallest snake examined (57.5 cm SVL) had eaten a Rattus sp. (Natusch & Lyons, 2012). Juveniles presumably also take skinks and frogs, as observed in other carpet python populations. The northern brown bandicoot (Isoodon macrourus), which matures at an average weight of around 500 g, represents a substantial meal even for a large adult – a useful reference when scaling prey size in captivity.

Breeding and Reproduction

Seasonality

Unlike their counterparts on the east coast of Australia, Papuan carpet pythons time their breeding so that hatching coincides with the monsoon season – the same strategy employed by Darwin carpet pythons in the Top End. In the wild, females deposit eggs in October and November, with hatchlings emerging in December and January (Mutton & Julander, 2022). In European captive conditions, the cycle is shifted: most mating occurs between November and February, with eggs laid between mid-March and late April, rarely extending into May (Mense, 2009).

Males reach sexual maturity at around 92 cm SVL – typically after two to three years – while females mature later, with the smallest mature female recorded at 147 cm SVL, after three to four years (Natusch & Lyons, 2012; Mense, 2009). Combat between males has been observed in captive specimens (Mutton & Julander, 2011) and is assumed to occur in the wild, though it has not been formally documented in free-ranging animals. The large size attained by males – the largest male in the Natusch & Lyons sample exceeded all females – is consistent with sexual selection driven by male combat (Shine & Fitzgerald, 1995).

Clutch Size and Hatchlings

Reported clutch sizes range from 8 to 27 eggs, with averages of 12–16 eggs (Mense, 2006) or 17 eggs from a sample of eight wild-caught females (Natusch & Lyons, 2012). Clutch size is significantly correlated with maternal body length (Natusch & Lyons, 2012). One exceptionally large wild-collected female deposited 33 eggs after three years in captivity (Mutton, pers. obs., as cited in Mutton & Julander, 2022).

Mense (2009) provides detailed data from nine captive clutches totalling 116 eggs (2006–2007): clutch sizes ranged from 9 to 16 eggs (average 12.89), eggs measured 53–59 mm × 36–40 mm and weighed 40–48 g, and total clutch weight reached up to 35 % of the female's body weight. At an incubation temperature of 31–32 °C and humidity above 90 %, hatchlings emerged after 50 to 65 days (average 58). The hatch rate was exceptional: 114 of 116 eggs produced viable offspring. Hatchlings weighed 20–34 g (average ♂ 27.25 g, ♀ 26.3 g) and measured 35–51 cm in total length (average ♂ 44.2 cm, ♀ 43.67 cm). With normal feeding, juveniles reached 89–109 cm and 235–350 g at 18 months.

Interestingly, hatchling size did not correlate with either maternal SVL, maternal mass, or maternal condition – despite significant differences in both hatchling SVL and mass between clutches (Natusch & Lyons, 2012). The proximate causes for these differences remain poorly understood.

Captive Breeding Notes

In captivity, a moderate dry-season cooling combined with a reduction in photoperiod is recommended to stimulate reproductive behaviour. The temperature parameters outlined above are sufficient. Ovulation is usually visible for approximately ten to twenty hours as a pronounced thickening between the middle and last third of the body. The pre-lay shed occurs approximately three to five weeks before egg deposition – in Mense's animals, typically 24–28 days beforehand (Mense, 2009).

An interesting behavioural observation: gravid females have been documented adopting a tight ball posture during the last three weeks of pregnancy – coiling their body in the same manner known from the defensive posture of the ball python (Python regius) (Mense, 2009). Underwater copulation has also been documented in this subspecies.

At StarPythons, we allow our breeding females adequate recovery time between clutches – reproduction is energetically costly, and females bred annually without sufficient rest produce smaller clutches and weaker offspring over time. The quality and well-being of our animals always take precedence over quantity.

Conservation and Trade

The Papuan carpet python is not currently considered threatened at the species level, and populations appear to be stable despite ongoing habitat loss and direct persecution. Their large distribution – most of which is remote and uninhabited – relatively high fecundity, and adaptability to human-modified environments suggest that current harvest levels are likely sustainable, though data remain insufficient for a rigorous assessment (Natusch & Lyons, 2012).

However, the conservation picture for this subspecies is complicated by the international pet trade. Indonesia is currently the only country that permits the legal harvest and export of wild carpet pythons. The national quota – 400 individuals in 2010 and 2011 – is divided equally between the provinces of Papua and West Papua (Natusch & Lyons, 2012). The problem is that carpet pythons have never been recorded in West Papua, meaning all wild-caught animals originate from Papua province. As a result, the effective provincial quota for Papua (200 animals) has been exceeded in every year since at least 2000 (Natusch & Lyons, 2012). The confusion appears to stem from wildlife traders in the city of Sorong (located in West Papua) historically receiving carpet pythons from Merauke, leading authorities to assume the species also occurs in West Papua.

Most animals collected for the trade are recently hatched neonates. Villagers collect gravid females, allow them to lay and brood their eggs until hatching, and then sell both the mother and the offspring separately to traders – removing a reproductive female and her entire annual output from the wild population in a single transaction (Natusch & Lyons, 2012). Animals are collected opportunistically near human habitation or while crossing tracks at night, then brought to traders in the port town of Merauke, sometimes from villages as far as 100 km away. There was no collection bias towards either sex (Natusch & Lyons, 2012). Conditions during holding are often poor, and it is likely that many animals exported as "farm-bred" are in fact wild-caught individuals laundered through Indonesian breeding farms that lack the facilities to genuinely breed reptiles at scale (Natusch & Lyons, 2012; Nijman & Shepherd, 2009).

Mark O'Shea reports a decline in carpet python encounters in the Port Moresby region over recent years, which he attributes primarily to killing by locals rather than to habitat loss (Mutton & Julander, 2022). The island of New Guinea as a whole is under increasing pressure from unrestrained development and forest clearing for palm oil plantations.

It is hoped that continued captive breeding efforts abroad will reduce the demand for wild-collected animals over time. At StarPythons, all our Papuan carpet pythons are captive-bred from documented lineages – we do not work with wild-caught animals.

Buying a Papuan Carpet Python: What You Should Look Out For

Looking for a Papuan carpet python? At StarPythons, we breed Papuan carpet pythons with a clear focus on health, genetics, and animal welfare. Here is what you should always insist on when purchasing.

Only Captive-Bred Animals from Responsible Breeders. The Papuan carpet python is one of the few members of the Morelia spilota complex that is still exported as wild-caught animals from Indonesia. We strongly recommend buying captive-bred animals only. Captive-bred animals are healthier, calmer, better adapted to captive conditions, and do not contribute to pressure on wild populations. If you are offered a wild-caught animal, be aware that it may carry parasites, may refuse captive food items, and is likely to be significantly more defensive than a well-socialised captive-bred specimen.

Health Check Before Purchase. A reputable breeder will be happy to show you their animals and provide full information about feeding history, shedding record, and health status. Watch out for noisy breathing, excessive mucus in the mouth, mites or skin changes, an unclean cloaca, or a lethargic, unresponsive animal.

Documentation and Legal Aspects. Like all carpet pythons (Morelia spilota), Papuan carpet pythons are listed under CITES Appendix II, which regulates international trade. Within the EU, no additional CITES permits are required for captive-bred animals – we provide all necessary documentation as standard. Reporting requirements vary by country and region. The seller is legally obliged to provide you with a certificate of origin. Never buy an animal without one.

Know What You Are Getting – Subspecies and Lineage Matter. The Papuan carpet python is closely related to both the Darwin carpet python and the Cape York populations, and mixed-lineage animals are not uncommon in the hobby. If you intend to breed – or simply want to know what you have – insist on documented lineage from the start. At StarPythons, all our breeding animals are documented with full lineage records, and we can trace our Granite lines back to the original Piet Nuyten collection from the 1990s.

Morphs and Genetic Varieties

The Papuan carpet python is the genetic foundation for several of the most celebrated morphs in the carpet python complex. Unlike the coastal carpet python, where most mutations were discovered in captive collections, the harrisoni morph palette has its roots in wild-caught founding animals imported from Indonesian New Guinea – and the stories behind these lines are as intertwined as the genetics themselves.

Granite

The Granite morph is a simple autosomal recessive mutation that disrupts the regular pattern structure of wild-type M. s. harrisoni, replacing it with a heavily fragmented mosaic of individually pigmented scales – a texture that gives the morph its name. The mutation was first produced in captivity around 2001 by the Dutch breeder Piet Nuyten, who had acquired a pair of imported animals around 1994. From this pair's offspring, Nuyten bred the F2 generation and discovered visual Granites among the hatchlings – proving the recessive inheritance.

Because the founding population was small, inbreeding depression emerged as a practical challenge in early Granite projects. Reduced vigour, fertility issues, and other signs of diminished genetic diversity were observed in some lines. Outcrossing to unrelated pure IJ animals was – and remains – the standard management practice to maintain the health and vitality of Granite lines over generations.

At StarPythons, we acquired our founding Granite animals directly from Piet Nuyten in 2007 and have maintained this primary lineage ever since. For detailed information on Granite genetics, biology, combination morphs, and available animals, visit our dedicated Granite Carpet Pythons page.

Axanthic

The Axanthic morph reduces yellow and red pigmentation by affecting the xanthophores and erythrophores, resulting in an almost monochromatic animal in shades of black, white, and grey. The mutation was proved out in 2008 by the Polish breeder Krzysztof Nowak, who paired a wild-caught male with a captive-bred female acquired from Marc Mense. Both animals appeared normal but were noticeably light-coloured. When Nowak bred the offspring, visual Axanthics appeared among them – demonstrating that the wild-caught male had been heterozygous for the trait. In 2023, Raphael Doll independently confirmed the presence of the Axanthic allele in a second wild-caught male, further establishing that this mutation exists in the wild population.

The inheritance of harrisoni Axanthic is currently classified as recessive, though some heterozygous animals display a noticeably lighter, greyish colouration – raising the possibility that the trait may be incompletely dominant. This question has not yet been conclusively resolved.

At StarPythons, our Axanthic animals trace back to the Nowak/Mense lineage.

Hypo

The history of the Hypo mutation in M. s. harrisoni is closely intertwined with the Axanthic and Granite lines. The captive-bred female that Mense provided to Nowak – one of the founding animals of the Axanthic project – turned out to carry the Hypo mutation. This means that the first visual Axanthics produced by Nowak were, in fact, Hypo Axanthics, though this was not understood at the time. The Hypo allele appears to have entered European collections through wild-caught imports in the 1990s and has been passed along, often unrecognised, through multiple breeding lines.

Hypo reduces dark pigmentation, producing brighter, cleaner animals – but the effect can be subtle in heterozygous form and was historically mistaken for natural variation. Recent breeding results suggest the mutation may be incompletely dominant, with a visually distinct super form, but this is still being actively investigated by several breeders.

At StarPythons, Hypo emerged as a byproduct within our Axanthic and Granite lines rather than as a targeted project.

Combination Morphs

The fact that Granite, Axanthic, and Hypo all originate within M. s. harrisoni makes this subspecies uniquely suited for subspecies-pure multi-gene combinations – something that is extremely rare in carpet python morph breeding, where most designer combinations require crossing subspecies.

Axanthic Granite (pure IJ): A double recessive combination of two harrisoni-native morphs. The Axanthic morph's strong reduction of yellow and red pigmentation combined with Granite's pattern fragmentation produces a high-contrast monochromatic animal – one of the most visually striking pure-subspecies combinations in the complex.

Ghost Granite (Hypo Axanthic Granite): A triple combination within M. s. harrisoni that layers Hypo's melanin reduction over the Axanthic Granite phenotype, producing an exceptionally pale, almost ethereal animal with the characteristic Granite pattern disruption.

At StarPythons, we work with both Axanthic Granite and Ghost Granite as pure IJ projects.

Common Mistakes (and How to Avoid Them)

1. Assuming They Are Darwin Carpet Pythons

The Papuan carpet python is closely related to the Darwin carpet python, and the two are sometimes confused or even deliberately mislabelled. While they share a similar ontogenetic colour change and adult size range, there are meaningful differences in temperament (Papuan animals tend to be more defensive), ecology (primarily ground-dwelling versus strongly arboreal), and, crucially, subspecific identity. If you are buying for a breeding programme, the distinction matters.

2. Underestimating Their Temperament

Papuan carpet pythons have a well-deserved reputation for being more defensive than some other carpet python forms. This applies to both wild-caught imports and, to a lesser extent, captive-bred animals. With consistent, gentle handling, most captive-bred individuals settle down, but new keepers should be prepared for an animal that may strike, musk, and bluff more readily than a comparable coastal or Darwin carpet python.

3. Overheating in Winter

These snakes come from one of the most thermally stable environments in the carpet python complex. Southern New Guinea experiences minimal seasonal temperature fluctuation. A winter cooling that mirrors protocols designed for diamond or coastal carpet pythons – deep drops over many weeks – is unnecessary and can stress the animal. A modest reduction is all that is needed.

4. Buying Wild-Caught Without Understanding the Risks

Wild-caught Papuan carpet pythons are still regularly available through the Indonesian export trade. While some WC animals can make perfectly good pets with patience and quarantine, buyers should be aware of the elevated risk of internal parasites, refusal of captive food items, and a significantly more defensive temperament compared to captive-bred specimens. Quarantine and a veterinary faecal screen are essential.

5. Ignoring Lineage

As with all members of the Morelia spilota complex, lineage documentation matters. The Papuan carpet python is closely related to both the Darwin and Cape York forms, and the differences are not always obvious by appearance alone. If you are buying for breeding purposes, insist on documented provenance. Within the Granite morph specifically, the founding lineage (Piet Nuyten or otherwise) is a critical piece of information that a reputable breeder should always be able to provide.

FAQ - Papuan Carpet Pythons

Is the Papuan carpet python suitable for beginners?

Yes. Papuan carpet pythons are manageable in size and hardy in captivity, which are points in their favour. However, they can tend to be more defensive than some other carpet python subspecies – particularly as juveniles – and wild-caught imports can be especially challenging. For a first-time carpet python keeper, a well-socialised captive-bred animal from a reputable breeder is essential.

How big does a Papuan carpet python get?

Most adults reach 1.5–2.0 m (4.9–6.6 ft). The largest wild individual measured 222 cm (7 ft 3 in) in snout-to-vent length and weighed just under 3,200 g. One wild-collected female reached 2.6 m (8.5 ft) after several years in captivity – but such sizes are exceptional.

What is the difference between a Papuan carpet python and a Darwin carpet python?

In the traditional classification used throughout the hobby, the Papuan carpet python (M. s. harrisoni) is the New Guinea form, while the Darwin carpet python (M. s. variegata) is the Australian form from the Northern Territory and Kimberley. Genetically, the two are very closely related – they were connected by land until roughly 6,000–9,000 years ago. Ecologically, the key difference is that Darwin carpet pythons are strongly arboreal (spending roughly 70 % of their time in trees), while Papuan carpet pythons appear to be primarily terrestrial. In terms of temperament, Papuan animals tend to be somewhat more defensive.

Why are they called "IJ" or "Irian Jaya" carpet pythons?

The name "Irian Jaya" refers to the former name of the Indonesian province on the western half of New Guinea, where most exported animals originate. The province was officially known as Irian Jaya from 1973 to 2002 and is now called Papua. The abbreviation "IJ" persists as a convenient shorthand in the hobby.

Are Papuan carpet pythons aggressive?

They can be defensive – more so than the average coastal or Darwin carpet python. Captive-bred animals from well-managed lines generally settle down with regular handling, but keepers should expect an alert and characterful snake that may strike or musk when it feels threatened, particularly as a juvenile. Wild-caught imports are typically more challenging in this regard.

How much does a Papuan carpet python cost?

Prices vary depending on age, lineage, and morph. Wild-type captive-bred hatchlings are generally available at moderate prices, while animals from documented Granite lines or proven breeding pairs command significantly higher prices. Rather than focusing on the lowest price, pay attention to lineage documentation, health status, and the breeder's reputation. Browse our current availability below to see pricing for your region.

Where can I buy a Papuan carpet python?

We recommend buying directly from an experienced, reputable breeder – like StarPythons. A good breeder will take the time to answer your questions, show you their animals and breeding facility, and provide full documentation including proof of origin and subspecific lineage. Avoid anonymous sellers on reptile exchanges or dubious online listings where health history, lineage, and subspecific identity of the animal are unknown.

References

Ciavaglia, S. A., Tobe, S. S., Donnellan, S. C., Henry, J. M., & Linacre, A. M. T. (2015). Molecular identification of python species: Development and validation of a novel assay for forensic investigations. Forensic Science International: Genetics, 16, 64–70. https://doi.org/10.1016/j.fsigen.2014.12.002

Esquerré, D., Donnellan, S., Brennan, I. G., Lemmon, A. R., Lemmon, E. M., Zaher, H., Grazziotin, F. G., & Keogh, J. S. (2020). Phylogenomics, Biogeography, and Morphometrics Reveal Rapid Phenotypic Evolution in Pythons After Crossing Wallace's Line. Systematic Biology, 69(6), 1039–1051. https://doi.org/10.1093/sysbio/syaa024

Hoser, R. (2000). A revision of the Australasian pythons. Ophidia Review, 1(1), 7–27.

Kaiser, H., Crother, B. I., Kelly, C. M. R., Luiselli, L., O'Shea, M., Ota, H., Passos, P., Schleip, W. D., & Wüster, W. (2013). Best Practices: In the 21st Century, Taxonomic Decisions in Herpetology are Acceptable Only When Supported by a Body of Evidence and Published via Peer-Review. Herpetological Review, 44(1), 8–23.

Mense, M. (2006). Rautenpythons: Morelia bredli, Morelia carinata und der Morelia-spilota-Komplex. Natur und Tier-Verlag, Münster. ISBN 978-3937285481.

Mense, M. (2009). Care and breeding of the Papua carpet python Morelia spilota harrisoni. Litteratura Serpentium, 29(2), 52–62.

Mutton, N., & Julander, J. (2022). The More Complete Carpet Python: A Comprehensive Guide to the Natural History, Care, and Breeding of the "Morelia spilota" Complex. ECO Publishing. ISBN 978-1938850424.

Natusch, D. J. D., & Lyons, J. A. (2012). Distribution, ecological attributes and trade of the New Guinea carpet python (Morelia spilota) in Indonesia. Australian Journal of Zoology, 59(4), 236–241. https://doi.org/10.1071/ZO11094

O'Shea, M. (1996). A Guide to the Snakes of Papua New Guinea. Independent Publishing, Port Moresby. 239 pp. ISBN 978-9980916969.

O'Shea, M. (2007). Boas and Pythons of the World. New Holland Publishers. ISBN 978-1845375447.

Available Pure IJ / Papuan Carpet Pythons (Morelia spilota harrisoni) Including Morphs

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