How do Komodo dragons keep warm?

Posted on: 14 March 2021 by Meghan Hill in March 2022 posts

My name is Meghan Hill and I am a final year MBiolSci student studying biological sciences. I am particularly interested in the field of animal behaviour and am currently undertaking a 1-year internship with the Behaviour and Welfare department at Chester Zoo while also completing my Master's studies.

The ability for reptiles to regulate their internal body at optimal temperatures is a key factor in their health and wellbeing, but since they can’t do this on their own, they must rely on environmental conditions to heat up, through basking, and cool down, by moving into the shade.

Currently, the most commonly used heat provisions emit radiation in the Infrared-B and Infrared-C wavelengths. These types of radiation heat by warming the surface of an animal, which can overheat the skin and, in extreme cases, lead to thermal trauma. Naturally, wild reptiles would receive radiation from the sun in the Infrared-A wavelengths, which heats by penetrating past the skin of an animal to warm tissues directly. Therefore, when reptiles bask under Infrared-A, their surface and core tissues are heated more evenly, making thermoregulation at optimal temperatures more sustainable and better for their welfare. New technologies have recently been developed that mimic the heat provided by the sun through emitting Infrared-A, and this equipment is increasingly being used in reptile husbandry. To monitor the effectiveness of heat provision, keepers often monitor the external body temperature of their animals. However, it is unknown whether this is a reliable method to determine if reptile species are reaching optimal core body temperature.

Chester Zoo have recently changed the heat provision for their two Komodo dragons to this new Infrared-A technology, and part of the research for my MBiolSci project is to examine the impacts of this on their thermoregulation through behavioural observations and measurements of internal body temperature compared to historic data. Internal body temperature is being recorded using data loggers which the dragons ingest with their food. External body temperature will also be recorded using a variety of equipment ranging in price and quality, which we will then compare to core temperature measurements to determine the reliability of the different equipment.

Although this is the first investigation, to the best of our knowledge, into the effect of Infrared-A on thermoregulation, the potential benefits that Infrared-A is predicted to have on the health and wellbeing of captive cold-blooded animals is extremely clear. As such this research may represent a turning point in reptile husbandry. Furthermore, effective thermoregulation is known to influence the fertility and reproductive rates of many reptile species. Therefore, this study also has the potential to increase the success of breeding programs working to prevent the extinction of endangered reptiles. By additionally investigating the reliability of different temperature recording equipment we will create evidence-based guidance for keepers on the most effective and accurate methods to monitor Komodo dragon body temperature which will ultimately inform best practice husbandry guidelines. This is particularly relevant for Komodo dragons as they have recently been moved from vulnerable to endangered, due to the effects of habitat loss and rising sea levels. Therefore, by improving heating facilities to maximise the health and welfare of Komodo dragons in captivity, and identifying standardized methods to record their body temperature, this project may help support the protection of this enigmatic species.

With thanks to Dr. Lisa Holmes and Dr Rebecca Jones for their feedback and assistance with this article.