Green tree pythons (Morelia viridis) are found only within the Australian region. These pythons are found throughout New Guinea and surrounding islands with the exception of the Bismarck Archipelago. They also occur in the Cape York Peninsula of Queensland, Australia. The juvenile yellow morph of Morelia viridis is found throughout this range, while the juvenile red morph is only found in parts of New Guinea.
Biogeographic Regions: australian (Native )
Distribution: Indonesia (Aru I, Irian Jaya), Papua New Guinea, Island of Gag, Australia (NE Cape York Peninsula of Queensland)
Type locality: Aru (as Aroe) Islands, Indonesia. Synonyms: azureus:
Type locality: Biak Island adelynhoserae:
Type locality: Normanby Island, d’Entrecasteaux Archipelago, Milne Bay Province, Papua New Guinea. Holotype: AM R129716. shireenae:
Type locality: Cape York, Queensland, Australia.Holotype: NMV D51862.
Morelia viridis reaches an average length of 1.5 meters; with the largest recorded specimen being 2.2 meters in length. The head scales are irregular and small and their labial heat-sensing pits are only found within the scales on the upper lip. Their tail is prehensile, helping them to climb. Green tree pythons do not appear to exhibit sexual dimorphism in adulthood; however, at smaller lengths juvenile females have both wider and longer heads when compared to males of similar size.
As adults, green tree pythons display a brilliant green over most of their bodies. On the dorsal surface there us a distinct ridge of scales that is usually white to yellow in coloration and forms a broken or continuous line down the length of the body. Ventrally, the scales are generally yellow. However, some individuals may have ventral scales of a more dull yellow to white and have a blue tinge scattered on the scales of the dorsal surface.
Juvenile green tree pythons may be either bright yellow or brick-red. Along the dorsal surface, they exhibit a series of white blotches edged in black or brown. These blotches may be either symmetrical or randomly placed on both sides of the body. In both color morphs, a white streak edged in black runs from the nostril through the eye and to the back of the head. The distributions of these two color morphs seem to be different, although it is not uncommon for both color morphs to be in the same clutch in captive situations. In the wild, only the yellow morph has been recorded in Australia. Although poorly studied, the red morph seems to be restricted to the island of Biak and the Baliem Valley in Papua, Indonesia and in the Sepik basin of Papua New Guinea. In some populations of Morelia viridis, the adults may not completely change to green and will maintain some of their juvenile yellow coloration.
Range length: 2.2 (high) mm.
Average length: 1.5 mm.
Other Physical Features: heterothermic
Sexual Dimorphism: sexes alike
Morelia viridis is a tropical rainforest species inhabiting mainly low montane and lowland rainforest habitat ranging from 0 to 2000 m. They may also be found in secondary forests and areas of re-growth. When young, green tree pythons restrict themselves to canopy gaps or along the edges of forest where light can easily reach the ground. As adults, they are generally found in closed-canopy rainforests.
Range elevation: 0 to 2000 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: rainforest
Habitat and Ecology
As with all other snake species, Morelia viridis is exclusively carnivorous. They are obligate ambush predators feeding on small reptiles, invertebrates, mammals, and birds throughout their lives. There is a distinct change in their feeding habits that coincides with the color change from red or yellow into their adult green coloration. Once they hatch out of the egg, their main prey consists of Carlia rostralis and diurnal invertebrates. In captivity, however, hatchlings have been known to cannibalize nest mates. Juvenile green tree pythons eat mostly small animals, such as lizards. As they grow in size, their gape gets larger and they are subsequently able to ingest larger vertebrate prey. In adulthood, green tree pythons eat mainly mammals and birds. For example, the main prey species for populations in the Iron Range of Cape York Peninsula, Australia are the rodents Rattus leucopus and Melomys capensis. Since they are ambush predators, green tree pythons do not move often and may use the same ambush site for up to 14 days, waiting for actively foraging prey to come within range. Caudal luring has been observed, especially in juveniles, where the tip of the tail is used to attract small animals. While an ambush feeding strategy does not yield prey often, green tree pythons have efficient digestive systems and do not require frequent feeding.
Animal Foods: birds; mammals; reptiles; insects
Primary Diet: carnivore (Eats terrestrial vertebrates)
As predators, green tree pythons help to reduce populations of several prey species of rodents, birds, and lizards. They also serve as food for several avian and terrestrial predators.
The main predators of green tree pythons are rufous owls, black butcherbirds, and an assortment of diurnal raptors. Other predators include mangrove monitors, dingoes, and New Guinea quolls.
The main anti-predator strategy of Morelia viridis is to avoid predation using its cryptic coloration and hiding behavior, which is especially effective against its visually-oriented avian predators. As juveniles, the yellow coloration blends in well in the rainforest edges where they are found. In juveniles with brick-red color, their coloration camouflages them better than yellow morphs against non-leafy backgrounds. It should be noted that in other species, red and yellow are typical warning colors to predators, however, green tree pythons do not appear to have any chemical defenses nor is there a dangerous model that they would be mimicking. As adults, green tree pythons inhabit the canopy of the forest and their brilliant green coloration blends in much better than either red or yellow. This suggests an adaptive basis for ontogenetic color change in this species.
- black butcherbirds (Cracticus quoyi)
- grey goshawks (Accipiter novaehollandiae)
- long-tailed buzzards (Henicopernis longicauda)
- Doria's hawks (Megatriorchis doriae)
- Meyer's hawks (Accipiter meyerianus)
- New Guinea harpy eagles (Harpiopsis novaeguineae)
- grey-headed goshawks (Accipiter poliocephalus)
- black-mantled goshawks (Accipiter melanochlamys)
- chestnut-shouldered goshawks (Accipiter buergersi)
- rufous owls (Ninox rufa)
- mangrove monitors (Varanus juxtindicus)
- dingoes (Canis lupus dingo)
- New Guinea quolls (Dasyurus albopunctatus)
Anti-predator Adaptations: cryptic
Life History and Behavior
Green tree pythons are solitary snakes, so the majority of communication is interspecific. They use their labial pits as well as sight when searching for prey. Labial pits allow for infrared imaging, which is particularly important given their nocturnal habits as adults. Labial pits may also serve to help these snakes find suitable ambush and thermoregulation sites as well as help them avoid possible predators. When finding potential mates, green tree pythons most likely use chemical pheromones as opposed to visual cues.
Communication Channels: chemical
Other Communication Modes: pheromones
Perception Channels: visual ; infrared/heat ; tactile ; vibrations ; chemical
Green tree pythons are about 30.5 cm in length when they hatch. At this stage, they are either bright yellow or brick-red. They must undergo ontogenetic color change in order to acquire their adult green coloration. This generally occurs between six months and a year of age, but does not coincide with sexual maturity, as might be expected. Instead, at this age, the juvenile python will be between 53 and 59 cm in length and is large enough to change its foraging behavior and habitat. Each color stage appears to provide camouflage suitable to its immediate habitat. As a young snake, the red or yellow color blends in better in forest gaps or edges, where smaller animals reside. Adult green coloration blends in best in the closed canopy of the rainforest, where larger prey live. The change does not generally associate with a shedding event and may happen as quickly as overnight or take as long as several months. Red individuals of Morelia viridis take longer to undergo this change as they first lighten to a yellow color, several patches at a time, and then subsequently change to their adult green color.
Information on actual ages in the wild is limited for Morelia viridis. However, a population at Iron Range on Cape York Peninsula, Australia had an average age of 3.4 years. It is predicted that these pythons could live for at least 15 years, with a maximum age of 19. Green tree pythons in captivity have lived only slightly longer with the record age set at 20 years old.
Status: wild: 12 (high) years.
Status: wild: 3.4 years.
Status: captivity: 20 (high) years.
Status: wild: 15 to 19 years.
Status: captivity: 20.6 years.
Lifespan, longevity, and ageing
Reproduction in the wild has never been reported for Morelia viridis and the mating system is unknown.
A majority of available information on reproduction has been published from hobbyists in the captive pet trade, though some speculation can be made from scientific research in situ. The lack of sexual dimorphism and the presence of an equal sex-ratio in green tree pythons suggests that males do not compete physically in male-male combat in order to mate with females. Instead, a male’s ability to obtain a mate may be primarily determined by how well they can search out a female. This is apparently why males do not maintain stable home ranges. Males appear to stop feeding when searching for a mate. Once the male has found a sexually mature female he will stimulate her with his cloacal spurs (vestigial digits) to make her receptive for mating.
Green tree pythons have a highly seasonal breeding cycle; however, few offspring are encountered in any one year suggesting that these pythons do not breed every year. The actual mating season in the wild is not known, though in captivity it can range widely from August to January and tends to be stimulated by the onset of low pressure fronts and storms. As is true for all pythons, Morelia viridis is oviparous. In the wild, females lay their clutches in October and then brood them for approximately 50 days, but this can range from 39 to 60 days. Hatching takes place in November, corresponding to the start of the wet season in the Australian region. At hatching, green tree pythons are approximately 30.5 cm in length and can be either brick-red or bright yellow. Reaching sexual maturity can take several years and can be long after they have changed into their adult green coloration. In males, sexual maturity reportedly occurs after 2.4 years and in females, sexual maturity occurs after 3.6 years.
Breeding interval: Green tree pythons have a highly seasonal breeding cycle; however, few offspring are encountered in any one year suggesting that these pythons do not breed every year.
Breeding season: Mating has not been recorded for green tree pythons in the wild. It can be inferred that egg laying occurs in October, as hatching takes place in November.
Range number of offspring: 6 to 32.
Range gestation period: 39 to 65 days.
Average gestation period: 50 days.
Average age at sexual or reproductive maturity (female): 3.6 years.
Average age at sexual or reproductive maturity (male): 2.4 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; sexual ; oviparous
Green tree pythons exhibit some maternal care by brooding their eggs before they hatch. In captivity, females have been observed coiling around their clutches. They will often shiver and contract their coils, apparently to produce metabolic heat and thus maintain an ideal brooding temperature, which ranges from 84 to 88 degrees Fahrenheit. Once the young hatch, however, there does not appear to be any parental care.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female)
Molecular Biology and Genetics
Barcode data: Morelia viridis
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Morelia viridis
Public Records: 10
Specimens with Barcodes: 11
Species With Barcodes: 1
The status of the Morelia viridis is undetermined as it is not listed on the IUCN Red List or CITES. However, populations may be vulnerable to harvest for the captive pet trade. A majority of the pet trade for the United States and Europe is supplied by populations in Irian Jaya, although there has been recent success in breeding individuals in captivity. In Australia, it is illegal to collect green tree pythons or import individuals that originated in New Guinea. Aside from the pet trade, these pythons are also vulnerable to habitat degradation through logging and slash and burn agriculture. Nevertheless, until their numbers can be accurately counted, it may be impossible to determine the status of this species in the wild.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: no special status
IUCN Red List Assessment
Red List Category
Red List Criteria
Relevance to Humans and Ecosystems
As with most animals, green tree pythons may bite in self-defense. However, there are no known adverse effects of this species on humans.
The bright red or yellow coloration of green tree pythons as juveniles and brilliant green coloration as adults has made them one of the most popular species of snake kept in the pet industry today. For this reason, Indonesia captively breeds Morelia viridis for export into the captive pet trade each year. However, even with captive breeding, wild populations are still under strain because a small number of snakes are captured illegally each year and entered into the trade. Green tree pythons are also hunted by the indigenous peoples of New Guinea for food.
Positive Impacts: pet trade ; food
Morelia viridis, the green tree python, or as it is known in the herpetoculture hobby, chondro (due to its former classification in the genus Chondropython.) is a species of python found in New Guinea, islands in Indonesia, and Cape York Peninsula in Australia.
The green tree python is characterized by a relatively slim body. The relatively long tail accounts for about 14% of the total length. The head is large and clearly
defined from the neck. The snout is large and angular. The body is triangular in cross section with a visible spine. The species usually reaches a total length of 150-180 cm (4.9-5.9 ft), but large females may reach 200 cm (6.6 ft). The size also varies depending on the region of origin. The weight is highly dependent upon the nutritional status of the animal. Males can weigh about 1100-1400 g (2.4-3.1 lb), females up to 1,600 g (3.5 lb). Especially large specimens up to 2,200 g (4.9 lb) are females, which like most snakes are slightly larger and heavier than males.
They are found in Indonesia (Misool, Salawati, Aru Islands, Schouten Islands, most of Western New Guinea), Florida U.S.A., Papua New Guinea (including nearby islands from sea level to 1,800 m elevation, Normanby Island and the d'Entrecasteaux Islands) and Australia (Queensland along the east coast of the Cape York Peninsula). The type locality given is "Aroe-eilanden" (Aru Islands, Indonesia).
Its main habitat is in rainforests, bushes, shrubs and trees.
The largest threat to the species is habitat destruction due to logging of forests.
Primarily arboreal, these snakes have a particular way of resting in the branches of trees; they loop a coil or two over the branches in a saddle position and place their head in the middle. This trait is shared with the emerald tree boa, Corallus caninus, of South America. This habit, along with their appearance, has caused people to confuse the two species when seen outside their natural habitat.
The diet consists mostly of small mammals, such as rodents, and sometimes reptiles. This snake, like the emerald tree boa, was thought to eat birds; however, Switak conducted field work on this issue. In examining stomach contents of more than 1,000 animals, he did not find any evidence of avian prey. Prey is captured by holding onto a branch using the prehensile tail and striking out from an s-shaped position and constricting the prey.
M. viridis is oviparous, laying 1-25 viable eggs per clutch. Breeding has never been reported from the wild, however in captivity eggs are incubated and protected by the female. Hatchlings are lemon-yellow with broken stripes and spots of purple and brown, or golden or orange-red. For yellow individuals at Iron Range National Park, Australia, the color change occurred over 5-10 days when individuals were 58-60 cm (22.8-23.6 in) long, which corresponds to about a year old. Colour change for red juveniles has not been observed in the wild.
These snakes are often bred and kept in captivity, although they are usually considered an advanced species due to their specific care requirements; once these are met, they thrive in captivity. Wild-caught individuals often carry parasites and don't always tame down, so have even further care requirements. The majority of captive-bred individuals, though, can be trained to accept handling. With the development of artificial incubation, this species became much more available in captivity. The most common method used was developed by Robert Worrell in the mid 1990s. It simply involved using a 50/50 ratio of vermiculite to water and just using a beverage cooler for an incubator. This, combined with the focus on embryo placement, allowed for a much higher hatch rate for this species in captivity. Later, Worrell's observation of ovulation allowed the average hobbyist to determine when oviposition would take place, as well as the outcome of the eggs. Green tree pythons lay their eggs roughly 40 days after ovulation, with the time extended up to a week when the animals are maintained in a cooler environment.
The caging for these animals is a bit more specific than the average python. As long as these requirements are met, the animal becomes very low maintenance. They require a higher relative humidity (60-80%) as well as a smaller fluctuation in temperatures (80-85F/26.5-29.5C) than most. Shiloh Hawkesworth wrote an article for Reptiles Magazine titled "Heat Seeker" "Heat Seeker" continuation going over these requirements. Among many who have kept this species, the green tree python has a reputation for being a furious reptile which will bite when provoked, but this is mainly limited to imported animals. Captive-bred green tree pythons are among the most gentle of all the python species.
A care sheet for this species can be found on the Reptiles Magazine website. This "care sheet" article was written by Rico Walder and Trooper Walsh.
5. Ron Kivit & Steven Wiseman (2005). The Green Tree Python and Emerald Tree Boa - Care, Breeding and Natural History. Kirschner & Seufer Verlag. ISBN 3-9808264-0-6.
- Schlegel, H. 1872. De Dierentuin van het Koninklijk Zoölogisch Genootschap Natura Artis Magistra te Amsterdam, Reptilia. 64 pp. (Python viridis, p. 54.)
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