Blue Tree Monitor (Varanus macraei)

Common Name: Blue Tree Monitor
Scientific Name: Varanus macraei
Source: CBID
Adult Size: Up to approximately 110cm (around 3.5ft) total length
Native Range: Batanta Island, West Papua, Indonesia

Enclosure: A minimum 120×60×180cm Viperia PVC vivarium — as an arboreal (tree-dwelling) species, height is essential. Furnish generously with sturdy branches, cork rounds, and hanging vines to allow natural climbing and perching, along with a bioactive or moisture-retaining substrate on the floor and secure hides at multiple levels.
Heating: Provide a basking spot of around 40–45°C, with an ambient (background) air temperature of 26–30°C throughout the enclosure. A night-time drop to around 22–24°C is acceptable and reflects natural conditions.
Humidity: Maintain humidity between 70–90%, mimicking the humid tropical forests of their island home. Use a reliable pressure sprayer or automated misting system, a moisture-retaining substrate such as coco fibre or cypress mulch, and ensure good ventilation to prevent stagnant air whilst keeping humidity high.
UVB: A 6% UVB tube run along most of the vivarium's width, positioned so the animal can bask approximately 20–30cm from the lamp. Blue tree monitors are diurnal (active during daylight hours) and inhabit forest environments with dappled sunlight, making consistent, high-quality UVB provision important for long-term health.
Diet: Primarily insectivorous — offer a varied diet of large insects such as dubia roaches, locusts, and black soldier fly larvae as the staple, supplemented occasionally with whole prey items such as pinky mice. Juveniles can be fed daily; adults do well on feeds every 2–3 days. Dust food items with a quality calcium and vitamin supplement at most feedings.

ABOUT THIS SPECIES

The blue tree monitor is one of the most visually striking reptiles in the hobby — a slender, agile lizard endemic (found nowhere else on Earth) to the small island of Batanta in West Papua, Indonesia, where it spends most of its life high in the forest canopy. Its vivid turquoise-blue scaling is extraordinary even among the famously colourful tree monitor group, making it a true centrepiece animal for any serious collection.

This species is best suited to experienced keepers who can reliably maintain the high humidity, tall enclosure, and precise temperatures it requires — it can be alert and quick, and typically rewards patient, low-stress handling over time rather than being immediately tame. For the dedicated enthusiast willing to invest in its care, the blue tree monitor is an exceptional and deeply rewarding reptile to work with.