Green Tree Python
Facts about this animal
This is an arboreal python, with a length of 1,5 - 1,8 m. It has a slender, laterally compressed body. Its head is diamond shaped and as in other pythons, the head scales are irregular, numerous and finely granular. The head also is much wider than and appears disproportional to the width of the body They have three thermosensory pits wirthin the upper and five to seven within the lower labials. These thermosensory (heat sensitive) pits help them notice changes in temperature, with which they are able to detect infra-red heat from warm-blooded prey. Their pupil is vertical. Adult green tree pythons have – irrespective of where they come from – different colours and patterns. There exist brilliant leaf-green specimens, but also individuals with yellow-green spots and even blue ones. Often, they are distinguished by a broken, vertebral stripe of white or yellow that runs down their back. Also, there may be flecks of blue, white, and yellow scattered over the body. This color pattern is a helpful tool in minimizing predation, as they tend to blend well with trees and bushes in which they rest. The underside is cream-white to yellow. Young animals are bright yellow or red, but also brick-red or brow-red with broken stripes and spots. They change colours at 6 to 12 months. Adults have a strong dentition with teeth up to 2 cm. That is the reason in addition to their particular position when resting in trees (see below) for the belief that birds – held fast with these long teeth - would be the main part of their prey. Indeed green tree pythons have a particular way of resting in the branches of trees: they loop a coil or two over the horizontal branches in a saddle position and place their head in the middle. And indeed C. viridis have a very interesting, confirmed method of luring their food to them: While lying very still on a branch they dangle their tail. When the prey, curious about the wiggling tail, gets close enough, they strike. Prey is captured by holding onto a branch using the prehensile tail and striking out from an s-shape position. But although they spend almost their entire life in the treetops, they are not exclusively tree-dwellers and can on rare occasions also be observed on the ground in particular at night. In fact evidence shows that they actively ground forage at night and sleep during the day. However they do not wander far. Like most snakes also the green tree python remains true to its site as long as there is enough food. Evidence has shown- contrary to belief – that they eat predominantly reptiles and small mammals (including such that live exclusively on ground). Despite many references in the literature, their diet, according to recent findings does not include birds. Though it has been reported to have taken place in all months of the year, the reproductive cycle occurs most frequently in the fall and winter months (September to October). After reaching sexual maturity (app. 2 years) they are looking for a sexual partner. If the female meets several males, several matings are possible with different partners. Copulation occurs when the pelvic spurs, which are found in both males and females, are used to anchor the male genital organs to the female cloaca. The male has two intromittant organs, called hemipenes but only one is engaged during mating. After successfully mating the females stop eating and are looking for a nesting site, predominantly hollows situated high in trees, but also other hidden sites that offer protection from enemies and enough humidity will be accepted. However in captivity, the female must have an elevated nesting box or the eggs will drop to the ground. The 5 – 35 eggs are deposited after 70 to 90 days (i.e. usually in February to March). The size of the clutch depends upon the size and age of the female. Like most python species also the green tree python protects and incubates its eggs. The female wraps her body around them and uses muscular shivers as a means of keeping or even increasing her body temperature, thus producing and keeping an incubation temperature of 29,5 o Celsius. If the temperature is too high she losens the body loops. On average, hatching occurs 45-65 days after the eggs are deposited. Since in principle matings, egg depositions and hatchings may happen any time of the year in this “non seasonal snake” this means that young can be seen any time of the year. They are about 30 cm long and have, as mentioned, very striking colours unlike from those of adults.
An extraordinary and most spectacular phenomenon in the animal kingdom is the change of colour in the young (“ontogenetic colour change”), as it is known also from some other snake species. When hatching, the colour of the young green tree pythons is a brilliant yellow, red or brown-red. Hatchlings from the same clutch may have different colours. At the age of six to twelve months their colour changes into the typical green. This colour change can be completed within a few days or a few weeks but can also last up to 2 or 3 years (in particular in specimens from Biak) and takes place completely independently from moulting. Green tree pythons from Biak change colour only to a certain extent. Adult specimens from this region often have still a significant portion of yellow colour, what makes them particularly attractive. The colour change seems also not to be influenced by the amount of food intake: Animals of the same clutch changed colours at the same time although some of them had eaten significantly less than others or even had to be force fed. Also other external stimuli do not seem to affect the colour change. The colour of the hatchlings gives no clue for the extent and intensity of the green colouration when adult. Indeed the mechanism for this colour change is not fully understood yet. Really remarkable is the fact that the young of the equally arboreal emerald tree boa (Corallus caninus) from Central and South America, which could, as adults, easily be mistaken for a green tree python (see below) also change their colour in their first year of life. Interestingly enough, also adult green tree pythons can still change colour: During ovulation females can become lighter coloured and during the gestation they can become slightly bluish. This bluish colour may persist after deposition of the eggs. Therefore “blue” adults are usually older females that have produce offspring several times and blue males can be found only very rarely.
The green tree python has a striking resemblance to the emerald tree boa (Corallus caninus) from South and Central America, with which it could be mixed up easily. Through adaptation to their very similar habitats and ways of life in different parts of the world these two Boidae species have become deceptively similar in their appearance. They therefore represent one of the most impressive examples of convergence in the world of snakes. “Convergence” or parallel evolution means a very similar design of the exterior through natural selection in not closely related species. Chondropython viridis is a representative of the Pythoninae, while Corallus caninus is a representative of the Boinae. However though the resemblance in appearance and behavior is strong, there are significant differences as well. At closer examination it can be seen that Chondropython viridis has very small granular scales on the top of its head, while the scales on top of the head of Corallus caninus are significantly bigger and have developed into shields. Also the labial pits are more distictive in Corallus caninus: 9 to 13 are between the scales of the upper lip (Supralabialia) and 11 to 16 between the scales of the lower lip (Infralabialia). While with Chondropython viridis fewer pits are within these scales not beween them. Corallus caninus grows to a larger size than Chondropython viridis. And last but not least Corallus caninus, like other boas bears live young, whereas like all other python species, C. viridis is oviparous.
Did you know?
The natives of Papua New Guinea call the green tree python „Jamumong“ and on the Indonesian part of the island some tribes call it „Ular hijau“. Both names, freely translated mean “green snake”. Its earlier denomination Chondropython viridis was derived from the greek words „kohndros“ meaning „with a rough surface“ and „puthon“, which means „snake-like dragon“ in the greek mythology. The species denomination „viridis“ means simply „green“.
|Name (Scientific)||Morelia viridis|
|Name (English)||Green Tree Python|
|Name (French)||Python arboricole vert australien|
|Name (German)||Grüner Baumpython|
|Name (Spanish)||Pitón arborícola verde|
|CITES Status||Appendix II|
|CMS Status||Not listed|
Photo Copyright by
Micha L. Rieser
|Range||Australia (Cape York), Indonesia (Misool, Salawati, Aru Islands, Schouten Islands , most of Western New Guinea) Papua New Guinea (including nearby islands)|
|Habitat||Morelia viridis inhabits tropical jungles, bamboo thickets, rain forests, and monsoon forests where vegetation is thick and the climate is very humid (80-95% humidity) and warm (28-35oC), from sea level up to 2000 m asl. It can be found however also at forest margins and in secondary growth, bushes and shrubs, occasionally even in gardens and hedges that surround buildings. As its name says, it is primarily an arboreal snake and can be found mostly in trees as high as 30 meters above ground, but occasionally also on ground.|
|Wild population||The largest threat to the species is habitat destruction, particularly in the Indonesian (western) part of New Guinea, which is being logged by the Indonesian government, but also hunting for food and for a limited skin trade.|