The research, led by Faith Polando and Jennifer Campbell of North Carolina State University together with Dustin Smith and Emily C. Lynch of the North Carolina Zoo, was published in Frontiers in Ethology. Twenty facilities participated in the effort, and the final behavioral dataset covered 35 Komodo dragons — 25 mature animals and 10 immatures — observed between May and September 2025. Observers used the ZooMonitor platform to record each animal’s behavior at one-minute intervals within five-minute focal sessions, three days a week across morning, afternoon, and evening blocks. Before any real data were collected, 56 observers had to pass a battery of video-based reliability tests, scoring an average of 92 percent, a level of rigor that matters enormously when dozens of people across the country are describing the same species with a single shared ethogram.

The team sorted everything the dragons did into three bins: inactive, active, and undesirable. Inactivity dominated the activity budget, and that was not necessarily alarming. The single most common behavior — lying down with the head raised, seen nearly half the time — is a classic basking posture in this species, and basking is not laziness. For an ectotherm, it is deliberate thermoregulation, the engine that drives metabolism, digestion, immune function, and vitamin D synthesis. The more telling number was the undesirable category: barrier-oriented behavior, the reptile equivalent of pacing along a fence line and a known red flag in reptile welfare assessments, appeared only about 1 percent of the time. In welfare science, stereotypies become concerning when they exceed roughly 10 percent of the activity budget, so the dragons in this sample were, by that measure, doing remarkably well.

The surprises emerged when the researchers crossed behavior with habitat. Using generalized linear mixed models with individual identity as a random effect, they found that age completely reversed the effect of being indoors or outdoors. Immature dragons — those rapid-growth juveniles under seven or eight years of age, depending on sex — were significantly more active in outdoor habitats, where they were a striking 8.05 times more likely to be active than mature individuals. Mature dragons showed the opposite pattern, hitting their highest activity levels indoors. Natural light told a similar story: young dragons with access to genuine sunlight were up to 3.81 times more active than those with merely filtered light, while mature dragons were actually most active in enclosures with no natural light at all, being 4.50 times more active there than under full natural light.

The explanation the authors propose is rooted in biophysics. Hatchling Komodo dragons begin life at around 0.1 kilograms and, as arboreal sun-shuttlers, occupy a very different ecological niche from the 87-kilogram terrestrial apex predators they eventually become. Small bodies have a high surface-area-to-volume ratio and low thermal inertia, meaning their internal temperatures swing quickly with the environment. The adaptive response is frequent movement — darting between sun and shade, riding thermal gradients in real time. A heterogeneous outdoor habitat, with its shifting light and variable thermal zones, invites exactly that behavior. A massive adult, by contrast, heats and cools slowly; it can afford long, sedentary basking sessions and passive strategies like shade-seeking, mouth-gaping, and burrow use. In a stable indoor enclosure, adults appear to compensate for limited cooling options by moving more, perhaps searching for suitable temperatures, while juveniles, deprived of dynamic gradients, simply settle into long, motionless basking under a fixed lamp.

Artificial lighting produced some of the study’s most consequential findings. Across indoor habitats, access to ultraviolet B light increased activity consistently, with dragons under UVB lamps 2.82 times more likely to be active than those without. That makes physiological sense: UVB drives vitamin D3 synthesis in reptile skin, and an animal that can meet its vitamin D budget efficiently is freed to spend less time basking and more time doing everything else. Previous work has already linked UVB exposure to vitamin D3 levels, egg production, and behavior in this species, so the new multi-institution data elevate what was a case-study observation into a population-level pattern. For any zoo keeping Komodo dragons indoors, the implication is blunt: UVB is not optional decoration, it is infrastructure.

Heat, it turns out, is not a one-size-fits-all variable either. In indoor habitats, both infrared lighting and heated surfaces significantly increased activity in females — 4.25-fold under infrared light and 1.69-fold with heated surfaces — but had no measurable effect on males. The authors offer two non-exclusive explanations. The first is size: adult female Komodo dragons are generally smaller than males, and smaller bodies reach optimal temperatures faster on warm gradients, freeing them for active heat-shuttling rather than prolonged basking. Larger males, with their greater thermal inertia, may simply be indifferent to supplemental heat because they hold their temperature regardless. The second is reproduction: female oviparous reptiles are known to shift their preferred body temperatures during breeding cycles, sometimes narrowing their thermal ranges, and access to infrared light or warm substrates may let them fine-tune their temperatures more precisely during those demanding periods. The authors caution that they lacked full weight and reproductive-status data, so both hypotheses await direct testing — but the sex-specific signal itself is already actionable.

The study’s scale is part of what makes it significant. Komodo dragons are held at 284 institutions worldwide through the Species360 network, yet the ex situ population has historically shown low growth rates and survivorship, and reptile welfare research in general has lagged far behind mammal-focused work, partly because welfare models built on domestic mammals translate poorly to ectotherms. Behavioral thermoregulation in reptiles is entangled with nearly every physiological process that matters — metabolism, immunity, digestion, reproduction — which means the way an animal basks is a window into whether its habitat is actually working. By demonstrating that simple, measurable design features — indoors versus outdoors, direct versus filtered versus absent natural light, the presence of UVB, infrared, or heated surfaces — produce statistically detectable shifts in behavior across a national population, the study converts habitat design from an art into something closer to an engineering discipline.

The practical recommendations follow directly from the data. Juveniles, the authors suggest, should be housed in heterogeneous environments with dynamic lighting and complex thermal gradients that change day to day, mimicking the environmental variation that drives their natural sun-shuttling strategy. Mature dragons may benefit less from dynamism and more from cooling opportunities — broader thermal gradients, burrows, and structural shade — that let their bulk work for them. And for females, supplemental heat options may be especially important, both for size-based thermoregulatory needs and potentially for reproductive ones. None of these interventions requires rebuilding an enclosure from scratch; they are adjustments to the wavelength, intensity, and geometry of light and heat, the very variables zoos already control.

There are honest caveats. The observation window spanned a single season, so seasonal effects remain invisible; sample sizes were unbalanced across habitat conditions, which the authors mitigated statistically but could not eliminate; and coarse grouping of lighting types obscures differences in intensity and placement that could matter at the level of an individual animal. Wild activity budgets for direct comparison are also scarce, making it hard to say definitively whether 72 percent inactivity is natural or a symptom of suboptimal provisioning — though the authors note that in other managed reptiles, inadequate lighting and heat force animals into longer inactive basking to meet their thermal requirements. Those gaps define the research agenda: year-round observations, sex-specific thermal studies, and attention to humidity, substrate, diet, and enrichment at similar scale. What the study establishes beyond doubt is a behavioral baseline for the entire managed population and a proof of concept that multi-institutional collaboration can turn dozens of zoos into a single, statistically powerful laboratory. For a species endemic to a handful of Indonesian islands and facing mounting pressure in the wild, that laboratory may prove to be one of its most important refuges.

Subject of Research: Effects of habitat lighting and heat provisioning on the behavior and welfare of zoo-housed Komodo dragons

Article Title: Effects of husbandry practices on Komodo dragon (Varanus komodoensis) behavior and welfare: a multi-institutional evaluation

Article References: Polando, F., Campbell, J., Opperman, L., Smith, D., & Lynch, E. C. (2026). Effects of husbandry practices on Komodo dragon (Varanus komodoensis) behavior and welfare: a multi-institutional evaluation. Frontiers in Ethology, 5, Article 1892185. https://doi.org/10.3389/fetho.2026.1892185

Image Credits: AI Generated

DOI: 10.3389/fetho.2026.1892185

Keywords: Komodo dragon, reptile welfare, zoo husbandry, thermoregulation, UVB lighting, behavioral ecology, activity budget, habitat design, multi-institutional study, ectotherms, animal behavior, zoos