11/02/2025
Yearly Reminder: Indonesian Blue Tongue Skinks DO NOT Brumate
Only their Australian cousins do - even then, not all of them decide to!
I have made this a yearly reminder since many places online do not actually differentiate and it gets really confusing!
The following temperature information is gathered from multiple studies that recorded ground temperatures within Indonesia and Papua New Guinea. If others have more recent (and therefore more accurate data), please provide the links and we will dig through and adjust!
Indonesian blue tongue skinks do not experience ambient temperatures below 70℉ (21.1℃). Indonesia/Papua New Guinea is a tropical climate that does not experience seasonal variation aside from “wet” and “dry” seasons caused by the amount of rainfall.
Due to the consistency in temperature in their tropical environment, Indonesian blue tongue skinks are active year-round.
💪🦎PHYSIOLOGY🦎💪
Reptiles are ectothermic, which means they need to warm up via their environment. They need heat to digest food; they need heat for their immune system to work and to fight off infections; they need heat for literally everything regarding bodily function.
If you put any reptile that doesn’t naturally brumate into too cold of an environment to “force” brumation, those reptiles become lethargic and can get quite sick due to their dropped immune system. They naturally shut down to try and preserve resources, as they cannot do anything without their proper heat range. This is not brumation. This is a physiological stress response. This can be very harmful to them!
Arguably, Indonesian blue tongue skinks experience this physiological stress in response to temps that are too cold. If your Indo is showing “brumation” symptoms, the environment is most likely too cold, too empty, or the animal is sick.
Winter in the northern hemisphere is the equivalent of dry season in Indonesia/Papua New Guinea. This means that our winters are the breeding season for Indos. It is quite common for some skinks to go off of food during this time due to hormones.
✨🦎BEHAVIOR & RECOMMENDATIONS🦎✨
If your skink is quite active, but not eating much, that is typically hormones. We recommend you triple check temps, but I would not be concerned.
If your skink is inactive and not eating much, triple check temps and make sure your skink isn’t going into shed. Going into shed is often a cause to hide more frequently and not eat - this behavior shouldn’t last more than 2 weeks at a time, however.
If your temps are too cold at night, please use a deep heat projector, ceramic heat emitter, or radiant heat panel to increase ambient temps - heat mats are not appropriate in this regard as they do not warm up ambient temps properly. Heat mats are not appropriate for blue tongue skinks in general.
If your daytime temps are too cold, you will either need to add a ceramic heat emitter/radiant heat panel or deep heat projector as supplemental heat. These are not appropriate for basking, they are only for supplemental heat. A deep heat projector assists with warming surface temperatures, while ceramic heat emitters or radiant heat panels assist with ambient temperatures. You may also need to look into increasing the wattage of the incandescent or halogen bulb used for basking.
Weigh adults twice a month - if they lose 10% or more of their initial body weight, that is a concern. (So if a 400 gram lizard loses 40 grams or more, that is a concern)
🦎☀RECOMMENDED TEMPERATURE & HUMIDITY RANGES☀🦎
INDO temps and humidity should be as follows:
✨Basking (surface temperature measured with an infrared laser thermometer): between 105-115℉ (40-46℃). Surface temperatures are naturally higher than ambient temperatures.
✨Ambient Cool Side (measured with a digital thermometer down at skink level, cool side of the enclosure): 70-80℉ (21-26℃)
✨Ambient Warm Side (measured with a digital thermometer down at skink level, warm side of the enclosure) : 85-95℉ (29-35℃)
✨Night time range: 70-75℉ (21-24℃) - We recommend providing supplemental heat when temps reach below 70℉ (21℃)
✨Humidity: Humidity for ALL Indonesians (yes, including Halmahera) must be within the 60-100% range. They naturally experience an increase and decrease in humidity within this range. It stays above 70% the majority of the year, but during the dry season (Northern Hemisphere’s Winter) it can drop as low as 60%. Humidity is naturally higher at night and lower during the day.
Please let me know if there are any questions!
References are in the comments!
