Sunday, March 15, 2009

Convert a Shelving Unit to a Rack System

I am raising a small collection of Green Tree Pythons and will only acquire 2 or 3 more animals over the next year. After doing my research, I quickly learned that rack-tub systems are ideal for keeping the neonate and small juvenile snakes until they are large enough for their display cages. The plastic tubs retain moisture and temperature much better than glass or acrylic aquariums, are very easy to clean, and are economically heated by the rack. For me the only downside to racks is that they tend to too big (10 tub minimum) and the custom built one’s were quite expensive and would take weeks to deliver.

I am not a carpenter, nor do I have access to good carpentry tools, nor do I have the carpentry skills to operate those tools. So rather than building my own rack-system, I opted to convert an Ikea shelving unit into a custom snake rack. I chose Ikea because it sells shelving units that measure 15 ¾” deep, perfect for 3 gallon tubs!

All in all, I spent about 3 hours of labor and less than $80 on the rack and tubs.

  • 1x BESTA shelving unit (23 5/8 " x 15 3/4 " x 15”) - $50(Ikea)
  • 4x SAMLA clear plastic box ( 11 " x 15 ¼ " x 5 ½ ", 3 gallon) - $2.99
  • 4x SAMLA clear plastic lid - $1.00
  • 4x SAMLA locking clips for lid (pack of 4) - $ .50
  • 8’ of 3” wide, 10 watt, Flexwatt Heat Tape – $16.80 (
  • Herp Power Proportional Thermostat – $119.00 (
  • 16x Plastic Hangers - $3.99 (CVS)
  • 1 regular extension cord - $2.99 (CVS)
  • Small handsaw
  • Drill
  • Soldering Iron
  • Solder
  • Wire Cutter/Stripper
  • Duck tape
  • Electrical tape

1. Assemble the shelving unit following the manufacturer instructions. The BESTA unit I purchased was very easy to assemble and took me roughly 20 minutes. These backs of these units come with a board that slides into pre-made grooves. I did not put the backboard into these grooves. Instead I nailed it to the back edges of the unit adding another ½” of depth to the unit to allow room for wires and cables.

2. Cut the flexwatt heat tape into four 23 inch strips, and wire the flexwatt as shown in the diagram. General information on wiring flexwatt can be found here. This link provides instruction on wiring flexwat in parallel. I chose to solder my connections and insulate with electrical tape.

I put two strips side-by-side on the base and two strips on the shelf. I keep my house relatively cool (68° - 70° F), the two rows of the 3"/10 watt flexwatt provides enough wattage to heat the back 6 inches of each tub up to an ambient basking temp of 88° F while the front half stays at 79°F. There is plenty of extra wattage so the thermostat can easily maintain the temperatures.

3. Secure the flexwatt to the shelving unit. I used the hand saw to cut a "v" shaped notch in the shelf to allow the wiring to pass to the base and secured the heat tape to the shelving unit using duct tape (foil tape would work well too). At this stage, the rack is complete.

4. Prep the tubs: Ventilation. There are two considerations that must be taken for converting the tubs into suitable habitats for GTPs: 1. ventilation, 2. perches. I used the soldering iron to melt ventilation holes into the plastic tubs along the rim spaced about 1" apart. I also made appropriate sized holes for the thermostat probe and thermometer/hygrometer probes.

I found that soldering holes is a fast and smooth process that does not leave jagged or sharp edges as can happen when the rpm of the drill used is not high enough. I also found that melted plastic smells like shit. Do this in a well ventilated area!

5. Prep the tubs: Perches. For perches I used plastic hangers I bought from CVS. With the handsaw, I cut the long ends off and then sized them so as to provide one long perch running down the depth of the container and two smaller perches cutting across. I made small perch-holes along the tub walls to secure the perches. This setup is stable enough to provide a secure perch for juvenile GTPs, while making the perches easily removable for cleaning and other husbandry needs.

That is pretty much it. Plug the flexwatt into the thermostat, set up your probes, and add substrate, decoration, and a water bowl and your set.

Sunday, March 8, 2009

Cage Requirements

The "ideal" cage size for captive Green Tree Pythons is hotly debated (see this posting in the morelia viridis forum). Most breeders opt for 24 x 24 x 24 inch cube cages for adults, and rack systems with 12-16 liter tubs for juveniles and 6 liter tubs for neonates. Each animal should be housed individually, chondros are not social creatures. The tub-rack system is an ideal way to keep younger snakes as it is easy to clean, easy to keep temperature and humidity, and very cost effective. I believe that for adult snakes the more room you can afford the better. They key is to give the animal a clean and stimulating environment to explore with enough stretching room to provide exercise.

Homemade Tub-rack sytem for 4 juvenile Chondros

Glass or acrylic aquariums and vivariums work well when properly modified to meet the heating and humidity requirements. I prefer custom cages as they can be optimally designed for chondros. If you are carpentry inclined you can build your own from wood or melamine board(Greg Maxwell provides plans to his cages here), or you can have one made for you from various cage manufacturers.

Greg Maxwell "style" cage. From

The cage should be furnished with plenty of well-secured perches and decorated with silk or live plants that allow the snake some coverage and a general feeling of security. Chondros are cautious animals and when given the choice between a high perch and proper temperature, they will almost always choose the safety of the high perch. This is why, contrary to popular beliefs, Chondros fare better in horizontally oriented cages as opposed to vertical “arboreal” cages. By placing the heating source off to one of the sides, we create a horizontal heat gradient that allows the snake to thermo-regulate along the perch while not having to sacrifice health and comfort for safety.

A water bowl with clean fresh water should be placed inside the cage. Despite chondros prefering to drink water droplets from their coils after a rain (or in captivity, a misting),they should be given the option of a constant clean fresh water source. To Maxwell’s point, give your snake the same water you would like to drink.The size of the bowl is inconsequential, note that a larger bowl can be useful if maintaing high humidity becomes a problem.

Newspaper and Paper towels work well for substrate as they are easy to clean and retain moisture. If you want a more natural look, I suggest Cypress mulch which smells great, looks great, retains humidity, and is easy to clean. Substrate should be replaced every 4-6 weeks and spot cleaned as needed.

Saturday, March 7, 2009

Localities and Chondro Races

When discussing localities and races of Green Tree Pythons it is important to consider the geographic barriers of the region. The Papua New Guinea mainland is divided into pockets of Chondro habitats by a central mountain range that at very least obstructs the cross breeding of localities and allows populations to develop in isolation. Generally we can state that there are strong racial traits amongst the north-western mainland localities that contrast to those of the south and south-west.

The island populations are separated from the mainland group by water and have had millennia to develop in isolation. Hence, island specimens tend to display stronger racial characteristics then the localities of the Papua New Guinea mainland.


Sorong and Jayapura Type

Sorong-types are a sample of the specimens found in the north-western region of the Papua New Guinea island near the coastal city Sorong. They commonly develop a sky-blue dorsal stripe and markings leading to a long and pointed black or dark blue tail against a light grass-green body.These north-western Chondros are the smallest of the localities and their small proportionate features and vibrant coloration accentuate an overall graceful and pretty serpent.

Jayapura Type
Presumably Jayapura-types are a sample of the specimens found in the central north-western mainland near the coastal city of Jayapura. Like Sorong's, they also small chondros and commonly develop a blue dorsal stripe and markings; however, the pastel-blue dorsal markings and olive-green body give these serpents a distinctly prehistoric aura.

Wamena and other Central Highland Types

Wamena and Central Highland types include the Arfak, Nabire, Lereh, and Cyclops localities. Highland animals are variable. They are distinguished from the Sorong and Jayapura types by unique small tear-drop shaped dorsal markings. Generally speaking, blue scales on these animals tend to be less bright than other mainland types. Some specimens also display black pigment on the edges of their scales.

Merauke and Southern Irian Jaya/PNG Types

Merauke and Port Mosresby are the southern coastal cities in the mainland of New Guinea responsible for exporting these south and south-western specimens. This locality produces beautiful and impressive animals with rich almost emerald green bodies split by a thin white dorsal stripe. The Merauke-type also extends to the south-western highlands, and it is possible that elevation may determine the appearance of the snakes. The theory is that higher elevations result in fully linear and more pronounce dorsal stripes. We should also mention that the only albino Chondro in captivity was hatched from Merauke parents.


Papua New Guinea was once connected to the Cape York Peninsula thereby explaining the genetic relationship between southern mainland specimens and these “Aussie Greens”. The most obvious visual trait of these snakes is the single row of irregularly spaced white or yellow scales on the dorsal ridge of a vibrant lime-green body.


Aru Island localities are characterized by having specks of white dorsal scales against a green or blue-green body color. Older specimens may develop gray scales mixed in with the white. They can also develop blue side and dorsal scales, and frequently a light blue wash covers the lateral and belly area. Aru localities tend to be larger than the mainland type as adults average about 60 inches in length.


Biaks are impressive beasts with robust heads, elongated dragon-like snouts atop a thick body. These are the largest of the Chondros. Their coloration is highly variable though they tend to be a predominantly olive-colored green. They typically have blotchy yellow patterns across their body particularly on their face and snout.


The Kofiau Island locality refers to specimens collected off the small Boo island chain to the west of the Sorong peninsula. Little is known about this rather newly discovered locality other than the fact that some adults tend retain their yellow into adult-hood.

Thursday, March 5, 2009

Natural Habitat

The beautiful Green Tree Python (morelia viridis), or “chondro”, lives in the tropical island forests of the south-eastern pacific. Their populations are distributed along the New Guinea land mass and nearby islands as far south as the Australian Cape York Peninsula. Being just south of the equator this regional climate is hot and humid with mild seasonal variation and nearly equal periods of day and night. Average daily temperatures range from 70°F (26°C) to 90°F(32°C).

While the wet season is November through April (monsoon season) ; it nonetheless rains year round. Annual precipitations vary from 79 to 197 inches (2,000 to 5,000mm) and are heaviest in the highlands. Like most rainforest climates, the humid heat built up during the day is relieved by strong afternoon thunderstorms.

Chondros primarily inhabit the rain forests and adjacent transitional re-growth areas, but not in the surrounding swamp and woodlands. They are common in open forests with significant sunlight penetration and in elevations from sea-level to 6,500 foot (2000m).

Researchers have observed wild specimens during the day coiled in branches from just above ground level to the top of the forest canopy. Chondros are nocturnal species, remaining perched and motionless during the day with their activity usually beginning around dusk when they descend to a hunting location a few inches above ground-level. Despite their name, Green “Tree” Pythons are surprisingly comfortable on the ground; in fact, some have been observed coiled and hunting from the forest floor.

Contrary to popular belief, chondros rarely prey on birds. Their diet consists of small mammals, such as rodents, and sometimes reptiles. This explains their habit of descending to hunt. Prey is captured by holding onto a branch using the prehensile tail and striking out from an s-shape position. Their explosive speed and agility when striking is nothing short of awesome.