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Blue Tree Monitor
Varanus macraei
One of the most spectacular monitor lizards in the world, adapted to arboreal life and featuring cobalt blue ocelli on a black body. It requires massive vertical enclosures, radiant heating, and expert care.
Class:Squamata
Order:Squamata
Family:Varanidae
Genus:Varanus
Species:Varanus macraei
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Environment
Terrestrial
Humidity
75 - 95 %
Day temperature
28 - 30 °C
Ambient temperature
28 °C
Night temperature
22 - 24 °C
Basking spot
40 - 42 °C
Adult size
36 cm
Minimum enclosure
>= 1,200 L
UVB
Medium
Species description
Geographical Origin and Habitat: This arboreal monitor lizard is endemic to the island of Batanta, located in the Raja Ampat archipelago of West Papua, Indonesia. It inhabits hot, humid tropical rainforests, living almost exclusively high in the forest canopy, shielded by dense tropical foliage.
Taxonomy and Genetics: Belonging to the family Varanidae, subgenus Euprepiosaurus, and is a prominent member of the Varanus prasinus species complex. There are no recognized subspecies. Its spectacular cobalt-blue coloration is a genetically fixed trait adapted for camouflage within heavily shaded, mossy rainforest canopies.
Behavior and Habits: Active, diurnal, and strictly arboreal. Highly agile, they possess sharp claws and a long prehensile tail used as a fifth limb for climbing. They are shy and wary by nature, seeking refuge behind tree trunks or in hollows when threatened. Males exhibit high territoriality.
Morphology: Sleek, slender, and extremely elongated body, reaching a total length of 100-110 cm, with the prehensile tail accounting for about two-thirds of this length. The dorsal ground color is black, covered with bright cobalt blue ocelli. Eyes are large with round pupils. Males possess wider heads and swollen tail bases.
Care, breeding and tankmates
Terrarium Setup: An exceptionally large vertical enclosure is required: minimum 150x80x180h cm for a single specimen or a pair. Decorate with a dense network of branches, live tropical plants, and cork bark tubes mounted vertically. A bio-active substrate at least 15 cm deep is recommended to maintain humidity.
Lighting and Heating: Essential to provide high-output 10% UVB lighting (T5) and powerful basking spots creating a localized temperature of 40-42°C (104-108°F). General daytime temperature should range from 28°C to 32°C (82-90°F), with a nighttime drop to 22-24°C (71-75°F). Use ceramic heaters or radiant heat panels for night warmth.
Humidity and Hydration: Relative humidity must be kept between 70% and 85%. An automatic misting system and a nighttime fogger are highly recommended. A large water basin must be provided on the floor, heated and cleaned daily, as they enjoy soaking.
Feeding and Supplementation: Voracious carnivores and insectivores. The diet must consist of large crickets, locusts, Dubia roaches, silkworms, quail eggs, and occasional rodents. Feeder insects must be dusted with calcium and vitamin D3 at every feeding for juveniles and twice a week for adults.
Compatibility: Males are fiercely territorial and must never be housed together. Compatible male-female pairs can coexist in massive enclosures, but must be monitored for breeding-related aggression. They are not compatible with any other reptile species.
Health and Common Diseases: Prone to dehydration and dysecdysis if humidity drops. Metabolic Bone Disease (MBD) is a severe risk under inadequate UVB. Respiratory infections can develop from cold drafts or sub-optimal temperatures. Specialized exotics veterinary care is mandatory.
Geographic Origin and Distribution
This arboreal monitor lizard is endemic to the island of Batanta, located in the Raja Ampat archipelago of West Papua, Indonesia. It inhabits hot, humid tropical rainforests, living almost exclusively high in the forest canopy, shielded by dense tropical foliage.
Origin
South and Southeast AsiaAustralia, New Guinea, and Oceania
Reptile profile
- Diet
- No verified data available
- Life expectancy
- No verified data available
- Adult size
- 36 cm
- Lifestyle/Microhabitat
- No verified data available
- Activity cycle
- No verified data available
- Sociality
- No verified data available
- Reproduction
- No verified data available
- Handling tolerance
- No verified data available
- Brumation
- No verified data available
- Molting
- No verified data available
The catalog's scalar value is 36 cm. The ReptTraits v1.2 source reports a maximum adult measurement of 36 cm for this species, recorded as snout–vent length (SVL). These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
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