Green Tree Python (Biak)

Morelia viridis
Common Names: Green Tree Python, Biak Green Tree Python

Species Overview

• Size: Adults typically reach 5–7 feet (1.5–2.1 m), with Biaks generally growing larger and more robust than many other localities. Females tend to be heavier-bodied.

• Appearance:

  • Biak locality Green Tree Pythons often display a darker emerald-green base colour, frequently with strong patterning in the form of scattered white, yellow, or blue scales.

  • Many individuals retain a “dirty” or patchy look, with irregular flecking and asymmetrical markings.

  • Neonates are born either red or yellow, later undergoing ontogenetic colour change into their adult form.

  • Some Biaks are known for retaining a mix of juvenile yellow and adult green, creating a unique mottled appearance.

• Distribution: Endemic to Biak Island, located off the northern coast of Papua (Indonesia).

• Habitat: Occupy tropical rainforests and coastal forest edges, spending most of their lives in trees and shrubs.

• Behaviour: Arboreal ambush predators, feeding on mammals, birds, and reptiles. They are alert and active, especially at night.

Captive Care

• Enclosure: Best housed in a tall arboreal enclosure, at least 36 inches in height, with multiple sturdy perches at varying levels.

• Temperature & Humidity:

  • Provide basking perches at 86–88°F (30–31°C), with ambient temps between 78–82°F (25–28°C).

  • Nighttime drops to 72–75°F (22–24°C) are recommended.

  • Humidity should remain 60–70%, with daily misting to replicate natural rainfall and support healthy sheds.

• Diet: Juveniles accept appropriately sized mice, while adults should be transitioned to small or medium rats offered every 10–14 days.

• Behaviour in Captivity: Biaks are notoriously more defensive and active than other localities such as Aru or Sorong. They are prone to striking if disturbed but usually calm when left to perch undisturbed.

• Special Considerations: Provide a naturalistic arboreal setup with numerous perches and visual barriers. A calm, minimal-handling approach works best with this locality.

Genetics Note

• The Biak Green Tree Python is a pure locality, not a morph.

• Designer lines do exist, but many breeders emphasize the importance of maintaining pure Biak bloodlines due to their distinctive size, colouration, and temperament.

The Green Tree Python (Biak) is one of the largest and boldest localities, known for its robust build, heavy patterning, and fiery temperament. While not always as calm as Arus, their striking appearance and commanding presence make them highly desirable among experienced keepers.