Green Tree Pythons: Characteristics, Behavior and Reproduction | Sea Life, Islands and Oceania

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GREEN TREE PYTHONS

green tree python

Green tree pythons (Morelia viridis) are a species of snake in the python family (Pythonidae) native to New Guinea, some islands in Indonesia, and the Cape York Peninsula in Australia. First described by Hermann Schlegel in 1872, they are bright in color as their common name suggests and can reach lengths of two meters m (6.6 feet) and weigh of 1.6 kilograms (3.5 pounds). They generally live in trees and mainly hunt and eat small reptiles and mammals. They are popular pets, and their numbers in the wild have suffered, especially in Indonesia, due to large-scale smuggling of wild-caught snakes. [Source: Wikipedia]

Green tree pythons were formerly known by the scientific name Chondropython viridis and were placed in their own genus. When scientists noticed the similarities with Australian and New Guinea carpet pythons, it was placed in the genus Morelia and given the scientific name Morelia viridis. In the pet trade, however, green tree pythons still go by the nickname “chondro”.[Source: Michael Hillman, Animal Diversity Web (ADW) |=|]

There can be considerable variation in color and patterning in green tree pythons. Because of this, some herpetologists and many hobbyists in the pet trade separate the species into variants or races. These include the Aru, Sorong, Biak, and Yapen. While these races aren’t recognized currently, additional research may suggest these variations warrant subspecies or species status. |=|

Green tree pythons are offered as an example of convergent evolution in reptiles. Their ecology and morphology is similar to that of emerald tree boas of South America even though they are not closely related. Both species live in tropical rain forest habitats and live mainly in trees. They are ambush predators and have similar diets and switch from being active during the daytime as juveniles to being active at night as adults. Green tree pythons and emerald tree boas also share the same resting and hunting postures and, remarkably, both species undergo ontogenetic color change from a red or yellow juvenile to a bright green adult. It can make it quite difficult to differentiate between the two species. One of the few ways to tell them apart is the position of the labial pits (small indentations on the lips of snakes). In emerald tree boas, the pits are on the upper and lower lip. Green tree pythons only have labial pits on the upper lip surface.

Green Tree Python Habitat, Range and Lifespan

green tree python range, from Bowling Green University

Green tree pythons are found in northeast Australia, throughout New Guinea and surrounding islands, except the Bismarck Archipelago. and many of the eastern islands of Indonesia. Those in Eastern Indonesia occur in Misool, Salawati, Aru Islands, Schouten Islands. Those in New Guinea are in Papua and West Papua in Indonesia and in found Papua New Guinea (including nearby islands, Normanby Island and the d'Entrecasteaux Islands. In Australia they reside in Queensland along the east coast of the Cape York Peninsula.

Green tree pythons live in tropical areas in rain forests at elevations from sea level to 2000 meters (6562 feet). The juvenile yellow morph of green tree pythons are found throughout their range, while the juvenile red morph are only found in parts of New Guinea. [Source: Michael Hillman, Animal Diversity Web (ADW) |=|]

Green tree pythons mainly inhabit low montane and lowland rainforest habitat. 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.

It has been estimated that the maximum lifespan of green tree python in the wild is around 12 years. A population at Iron Range on Cape York Peninsula, Australia had an average age of 3.4 years. It has been suggested that these pythons could live for at least 15 years, with a maximum age of 19. The record lifespan for a green tree python in captivity is 20,6 years.

Green Tree Python Characteristics and Colors

Green tree pythons have an average length of 1.5 meters (4.9 feet); with the largest recorded individual being 2.2 meters (7.2 feet in length). Sexual Dimorphism (differences between males and females) is not present: Both sexes are roughly equal in size and look similar. However, at smaller lengths juvenile females have both wider and longer heads when compared to males of similar size.[Source: Michael Hillman, Animal Diversity Web (ADW) |=|]

As is true with most snakes and reptiles, green tree pythons are heterothermic (having a body temperature that fluctuates with the surrounding environment). Their 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.

brick-red morph of green tree pythons

Adult green tree pythons are a brilliant green over most of their bodies. On their back is 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. The scales on their undersides are generally yellow. Some individuals may have scales on their backs that are dull yellow to white and have a blue tinge scattered on the scales.

Juvenile green tree pythons may be either bright yellow or brick-red. Along their back they have 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 the bright yellow or brick-red color morphs, a white streak edged in black runs from the nostril through the eye and to the back of the head. The ranges of the two color morphs are generally be different, but there is some overlap and its is not uncommon for both color morphs to be in the same clutch of captive females. 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 green tree python adults may not completely change to green and keep some of their juvenile yellow coloration.

Green Tree Python Diet, Hunting and Predators

Green tree pythons are exclusively carnivorous (eat meat or animal parts) as is true with all snakes. 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 longipes (a species of skink) and invertebrates that are active in the day. In captivity, hatchlings have been known to cannibalize nest mates. [Source: Michael Hillman, Animal Diversity Web (ADW) |=|]

yellow morph of green tree pythons

Juvenile green tree pythons eat mostly small animals, such as lizards. As they grow in size, their mouth size and gape get larger and they are able to ingest larger vertebrate prey. In adulthood, green tree pythons eat mainly mammals and birds. The main prey in the Iron Range of Cape York Peninsula, Australia are the Cape York rat and Cape York melomys — both rodents. As they are ambush predators, green tree pythons do not move much 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. This means the tip of the tail is used as a worm-like lure to attract small animals. Their ambush feeding strategy does not yield prey often but green tree pythons have efficient digestive systems and do not need to eat so often.

Known predators of green tree pythons, especially juveniles, including black butcherbirds. grey goshawks, long-tailed buzzards, Doria's hawks, Meyer's hawks, New Guinea harpy eagles, grey-headed goshawks, black-mantled goshawks, chestnut-shouldered goshawks, rufous owls, mangrove monitors, dingoes and New Guinea quolls. The main defense of green tree pythons is coloration, which serves as good camouflage in their rainforest environment. Hiding among the leaves and hardly moving also helps, especially against sharp-eyed birds of prey. The brilliant green coloration of adults blends in well with upper canopy vegetation where they spend most of their time. The yellow coloration of juveniles blends in well in the rainforest edges where they like to hang out. The brick-red color of some juveniles camouflages them better against non-leafy backgrounds.

Green Tree Python Behavior

Green tree pythons are arboreal (live mainly in trees), diurnal (active during the daytime), nocturnal (active at night), sedentary (remain in the same area) and solitary. Only female green tree pythons have distinct home ranges. They varies according to the length of the snake, and average 6.21 hectares (15.3 acres). Females are not territorial (defend an area within the home range), as they may share a large portion of their home range with other females as well as with roaming males and juveniles. Neither adult males nor juveniles have distinct home ranges. Males have adopt a mate-searching strategy, while juveniles presumably disperse from the nest.[Source: Michael Hillman, Animal Diversity Web (ADW) |=|]

Green tree pythons are mostly arboreal though they are occasionally found on the ground. Adults, hunt primarily at night as that is when their larger nocturnal prey are most. Juveniles are more diurnal (active mainly during the daytime), which is when their smaller prey are most active. Green tree pythons have two main postures depending on whether they are resting or hunting. In a resting posture, the snake’s body is coiled up and hanging on a horizontal branch or vine. This is how the animal is generally depicted in photographs. When resting, green tree pythons often take shelter in tree hollows or epiphytic vegetation. In a hunting posture, the front part of the body is extended from the branch and folded like an accordion, ready to strike at the ground or at a lower branch, while end of the snake is wrapped securely around its perch, usually a branch. Green tree pythons typically change between these postures only during dusk or dawn to avoid giving away their location. |=|

Activity rates vary according to sex, time of day and season. Females are more likely to change their position from day to day than are males. They are also more active and move further in the month of February. In contrast, males are more active in January and March. However, from about April until the start of the next breeding season in October, both sexes are sedentary and inactive. When moving, distances traveled by adult snakes are equal to the distances traveled by juveniles, regardless of their comparatively smaller size. |=|

Green tree pythons communicate with chemicals usually detected by smelling and pheromones (chemicals released into air or water that are detected by and responded to by other animals of the same species) and sense using vision, infrared light, touch, vibrations and chemicals. They use their labial pits (depressions in the lips that detect infra-red radiation) as well as sight when searching for prey. Labial pits are particularly advantageous when hunting at night as the body heat of prey shows up well in infrared imaging. Labial pits may also help thes snakes find suitable ambush and thermoregulation sites and avoid possible predators. When finding potential mates, green tree pythons most likely use pheromones.

Green Tree Python Mating, Reproduction and Offspring

Green tree pythons are oviparous, meaning that young are hatched from eggs. The mating of these snakes in the wild has never been observed. Most of what is known about their reproduction is based on information from captive snakes in zoos and pets. Green tree pythons have a seasonal breeding cycle; however, the mating season in the wild is not known, In captivity it range widely from August to January and tends to be stimulated by the onset of low pressure fronts and storms. Few offspring are encountered in a given year suggesting that these pythons do not breed every year. In Australia, egg laying occurs in October, and hatching takes place in November, which corresponds with the start of the wet season. The gestation period ranges from 39 to 65 days, with the average being 50 days. The number of eggs laid ranges from six to 32. On average females reach sexual or reproductive maturity at age 3.6 years and males do so age 2.4 years. [Source: Michael Hillman, Animal Diversity Web (ADW) |=|]

The lack of sexual dimorphism and 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 search out females. This appears to be the reason 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 stimulates her with his cloacal spurs (vestigial digits) to make her receptive for mating.

In captivity, females have been observed coiling around their clutches of eggs. 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.

When they hatch, green tree pythons are approximately 30.5 centimeters (one foot) in length and can be either brick-red or bright yellow. They undergo color changes before acquire their adult green coloration. According to Animal Diversity Web: 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 centimeters 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 Green tree pythons 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.

Green Tree Pythons, Humans and Conservation

On the International Union for Conservation of Nature (IUCN) Red List, green tree pythons are classified as a species of Least Concern on the IUCN Red List. While some populations have experienced declines due to habitat loss and the pet trade, the species as a whole is not considered threatened.

The bright red or yellow coloration of juveniles and the brilliant green coloration of adults has made green tree python a highly sought-after in snake pet trade. In Indonesia, they are captively breed for export. However, even with captive breeding, a number of snakes are captured and illegally and smuggled for the pet trade. Green tree pythons are also hunted by the indigenous peoples of New Guinea for food. [Source: Michael Hillman, Animal Diversity Web (ADW) |=|]

The majority of the green tree pythons sold in pet trade in the United States and Europe are from Papua and West Papau (the Indonesian part of New Guinea formerly known as Irian Jaya). Some are also breed in captivity in Australia. 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 threatened by habitat loss and degradation mainly from logging and slash and burn agriculture.

Image Sources: Wikimedia Commons

Text Sources: Animal Diversity Web animaldiversity.org , National Geographic, Live Science, Natural History magazine, Australian Museum, David Attenborough books, Australia Geographic, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The Conversation, The New Yorker, Time, BBC, CNN, Reuters, Associated Press, AFP, Lonely Planet Guides, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.

Last updated August 2025