types of green tree pythons

Types of Green Tree Pythons

One of the undeniable attractions of this beautiful species is the myriad of colour variations and combinations that can be seen.  Adult colouration can include various shades of blue, yellow, black, white and green, while hatchlings or neonates can range from bright yellow to brown to rich, dark red and even black.  The result is an almost endless array of different forms and stunning variety between individuals, commonly even within a clutch.
Captive Green Tree Pythons can be broken down into two categories:

  1. Wild type or pure line animals (difficult to prove due to lack of records or proof of provenance)
  2. Mixed locality type or crossed animals (including morphs and designer types)

Each of these categories can be further broken down based on characteristics displayed by individuals.

GTPs natural range is a small area of far North Queensland in Australia, mainland Papua New Guinea and several provences of Indonesian New Guinea.  Many of the locality types in the hobby are named after the towns in Indonesian New Guinea where the animals are exported from.  While the Indonesian government allows the farming of this species for legal export to various countries, including the USA, the Australian government does not allow the importation of them to our shores.  The truth is very few of our GTPs can be proven to be a particular locality, but by looking at factors such as colour, pattern, tail characteristics and head shape a well educated guess can be made. Animals from PNG regions are much less known in the captive pet trade as there is no legal export allowed.

gtp distribution

Southern Types

Australian type

Aussie gtpThe Australian GTP’s or ‘Aussie Greens’ are located in Iron, McIlwraith & Kawadji-Ngaachi Ranges of Cape York, Queensland.  Native Aussie GTPs have yellow hatchlings with brown markings and typically change to green at between about 7 to 11 months of age.  Adults are green and characterised by varying amounts of white scales down their dorsal (back) line. The amount of vertebral markings on both wild and captive bred animals can vary from almost none to a nearly complete white stripe. It appears to be more common for wild animals to possess a greater amount of white than captive bred animals. What causes this white stripe is unknown and many breeders are trying to replicate the stripe in captive bred animals.

More Aussie images by D. Natusch (click to see larger images)

Aru type

Aru gtpThe Aru Islands are located south west of New Guinea.  GTPs originating from Aru can be a bluey-green or a rich, mossy shade of green. They tend to have clusters of white scales along their dorsal line, as well as scattered white scales over their sides.  Some Aru animals also show blue, particularly on their sides and belly region. They are known for having relatively short, stumpy tails. Hatchlings are yellow with brown markings.


More Aru images by D. Natusch (click to see larger images)


Northern Types

Biak type

biak gtpBiak Island is a small island off the Northern coast of Indonesian New Guinea. Other nearby localities including Yapen and Numfoor are sometimes refered to in herpetoculture, however for our purposes they are included here simply under the ‘Biak type’ banner.

Biak type animals are known for their motley look and variability. They are commonly olivey green in colour, often with yellow blotches over their body, including the face.  Some white scales may be present and black between the scales is not uncommon.  Biaks often have large bodies, long, sharp pointed tails and bulky heads with a long snout and prominent nostrils. Hatchlings can be yellow or red in colour. Biaks take longer to complete their ontogenic colour change compared to most other forms, with individuals tending to hold more yellow into maturity. Many Australian keepers follow the proven belief of overseas breeders that Biak outcrosses produce or are the link to most future designer lines.

More Biak images by D. Natusch (click to see larger images)

Sorong type

sorong gtp

GTPs from the Vogelkop Peninsula and Raja Ampat regions in western Indonesian New Guinea are commonly referred to as 'Sorong type' after the largest city in the area. Mores specific localities sometimes referred to within herpetoculture include Manokwari, Arfak, Misool, Waigeo and Salawati. Animals from these localities are similar in appearance we will include them all under the 'Sorong type' banner.

Sorong type animals are characterised by an almost unbroken blue dorsal line with blue triangle patterns on either side of the line.  Blue spots can often be seen on the animals’ sides and some white scales may be present. Their tails are generally longer and more tapered than some other types and are blue or black on the tip.   Hatchlings can be red or yellow with a dark stripe along the dorsal line. There has become a trend in Australia for any animal showing signs of blue to be labelled Sorong type (or incorrectly Sarong type). Many of these animals are in fact mixed locality and do not exihibit the characteristics of Sorong type animals.

More Sorong images by D. Natusch (click to see larger images)

Jayapura type

Jayapura gtpGTPs originating from east of Nabire throughout Northern New Guinea, are commonly labelled as Jayapura type after the largest city in the region. Other localities known to herpetoculture from around the Jayapura area that are falling under the ‘Jayapura type’ banner in this section are Lereh, Cyclops Mountain and Arso.

Jayapura type animals are usually recognised by their light blue dorsal patterning which is generally more subtle when compared to animals from the Vogelkop Peninsula such as Sorong type. Their green tends to be more olive; yellow is often present on the lower sides and white scales can appear over the body. Hatchlings can be either yellow or maroon.

More Jayapura images by D. Natusch (click to see larger images)

Mixed locality/Crosses

mixed gtpMany of the GTPs in the Australian hobby and pet trade are of mixed locality or origin. This can be attributed to several factors including the lack of information about specific locality types until recently and the lack of animals in captivity to choose from for breeding purposes. Unfortunately all too often we see these animals labelled as a certain locality type when they are in fact a cross. This is most likely due to a combination of ignorance and the higher value placed on more pure lines. There is nothing wrong with saying a GTP is from unknown origins or mixed backgrounds.

Often you will hear breeders use the term ‘outcross’ (OC). This is usually used to describe a GTP that displays most characteristics of one locality type, but it is not from a pure line. For example, a Biak OC animal has clear and distinct Biak traits but its heritage includes some other origins.

More mixed images by M. Cermak (click to see larger images)


Designer Morph type

‘Designer morph’ lines are very much in their infancy in Australia.  Several GTP keepers are working on selective breeding for a particular trait to produce some incredible looking lines of animals.

Mite Phase - High Black - Melanistic

mite phase gtpThere are now a few lines of GTPs available that produce a certain amount of black scales. We are a long way behind some of the overseas high black GTPs, but we have to start somewhere! It’s important to point out- some lines of GTPs go through a very high black ontogenetic colour change. Don’t call it too early - wait until your GTP is through its colour change & closer to 3 years of age before claiming to have a high black. Buyers, be aware of what you are buying with realistic expectations.

High Yellow

Firstly, there has recently become a trend in Australia where some people are calling their GTPs ‘Lemon Tree’. This is a very confusing and misleading title to be giving a high yellow line in Australia because there is a well known designer morph line of GTPs in America known as ‘Lemon Tree’. The origins of this line can be read about in the book ‘The More Complete high yellow gtpChondro’. Australia does not have this line of ‘Lemon Tree’ GTPs. Perhaps some confusion crept in when Snake Ranch produced a beautiful high yellow animal and named him ‘Mr Lemon’. He was bred from animals bought in Australia and there was no American ‘Lemon Tree’ in this bloodline. Most high yellows in Australia are in fact Biak type. A Biak type ontogenic colour change takes much longer to complete than most of the different types. Again, buyer beware - a two or three year old Biak type may still hold a lot of yellow but is likely to turn mostly green by the time its five or six years old. There are some true high yellows being developed now, mostly from Biak type outcrosses, and with line breeding hopefully we will see some great high yellow examples sooner rather than later!

High Blue

Many of the Northern types, such as Sorong type, have a certain amount of blue down their backs or vertebral scales. A clue to predicting the amount of blue these animals will retain after their colour change is to look at its neonate markings - the dark markings on these hatchling will turn blue. The Aru Islands types have also been reported to have certain amounts of blue, particularly on their belly and flanks. These are all naturally occurring blue animals and not designer 'high blue', like we’ve seen developed overseas.

hormonal blue gtpSome gravid females take on a blue wash which increases each time time she breeds. This is referred to as 'hormonal blue' and is shown in the image (left). In many cases this leaves the female a striking blue colour overall. This is unfortunately not a genetic colour trait that will be passed on to hatchlings other than if the young females grow out to have a clutch of their own and they go on to show this visual characteristic. A hormonal blue female should not be named or marketed as a 'high blue' animal.


Rumours persist that albino GTPs are present in Australia.  Although rare, this is a naturally occurring mutation in many species.  We will have to wait and see if albino GTPs become available on the Australian market.

Common misunderstandings in the Australian hobby

All red babies are Biak type.

This comment is incorrect, many Northern types produce red babies and many of these types have been mixed with southern types. Red babies can have various backgrounds.

If it doesn’t have a continuous white stripe down its back it isn’t Aussie type.

This comment is incorrect; some wild Aussie GTPs have been observed without the stripe and also captive breeding of some localities appears to result in a reduction of white scales. Many keepers are working on different theories as to why this could be and some progress has been made in this area.

My GTP has blue so it’s a Sorong type.

Maybe, but many different types have blue, not only Sorong. Do your research if unsure.

My GTP is going through colour change and it’s developed some black scales - it's a mite phase.

Don’t call it too early! If your GTP is still in colour change it’s likely it will lose most of the black.

I’m buying a ‘high blue’ hatchling – I’ve seen photos of the mother and she is blue all over. 

It’s unlikely that hatchlings will turn out blue.  This is a common hormonal effect where females that have had several clutches turn blue.  Ask to see photos of her prior to laying and ask to see photos of the father as well.