reptile

Try Before You Buy: How Experience Shapes What Bearded Dragons Prefer

/ gtattersall

A recent paper from the lab, led by PhD student Melanie Denommé, examines a foundational assumption in reptile husbandry: that animals will inherently prefer naturalistic enclosures over simpler, more utilitarian ones. Using bearded dragons (Pogona vitticeps) as a model species, Melanie conducted preference tests in which lizards were given free choice between naturalistic and standard enclosure styles (Figure 1). Critically however, individuals had been reared under two different housing conditions and tested at multiple time points across their lives, allowing us to shed light on preferences shaped by experience. Contrary to expectations, the dragons did not show an immediate or universal preference for the more naturalistic enclosures. Instead, their choices were strongly influenced by prior housing conditions, age, and timing of the tests, demonstrating that familiarity and developmental context play an important role in how captive reptiles evaluate their environments. 

Figure 1. Graphic abstract from the study, describing the timing of the preference tests and housing conditions lizards were under at the two time points when preferences were tested. The y-axis describes a bias index, describing what proportion of time lizards spent within each enclosure style (values of 0 indicated 100% of time spent in standard, values of 1 indicate 100% of time spent in naturalistic).

Despite the absence of a consistent enclosure-level preference, the behavioural data told a more nuanced and compelling story. When lizards engaged in key species-typical behaviours such as climbing, digging, and hiding, they overwhelmingly used naturalistic resources rather than the simpler substitutes provided in standard enclosures. This finding suggests that while reptiles may not always “choose” a naturalistic enclosure outright, these environments are clearly superior for facilitating motivated behaviours that are closely linked to welfare. As part of Melanie’s broader PhD research program, this work emphasizes the importance of empirically testing husbandry assumptions rather than relying only on tradition or aesthetics alone, and it provides concrete guidance on which enclosure features matter most from the animal’s perspective. More than that, we argue that context and experience are important considerations in these kinds of studies.

Citation

Denommé, M and Tattersall, GJ. 2026. Try before you buy: Preferences for naturalistic-style enclosures are influenced by experience in bearded dragons (Pogona vitticeps). Journal of Applied Animal Behaviour Science, 295:106887. https://doi.org/10.1016/j.applanim.2025.106887  

Unlocking the Motivations of Repetitive Behaviours in Reptiles

/ gtattersall

Our latest study (https://doi.org/10.1016/j.applanim.2024.106484) sheds light on a perplexing behaviour seen in captive reptiles, namely their interactions with barriers (IWB), a form of repetitive behaviour akin to pacing in mammals. As part of her PhD research, Melanie Denommé investigated the motivations behind IWB in bearded dragons (Pogona vitticeps; Figure 1) over a three year period, and formally tested whether it stems from a “desire” to escape their enclosures.

Figure 1. Photo of a bearded dragon interacting with a barrier (called glass surfing sometimes if the lizard moves back and forth across the transparent barrier, although reptiles may do this on non-transparent barriers as well).

Our findings revealed a strong preference for performing IWB near the front barrier of their environment (Figure 2), the only known escape route; even when half of it was obscured; they also direct more of their behaviour toward the transparent part of the front barrier. Interestingly, IWB was 15 times more likely to occur around the time when lizards defecated, supporting an argument that these behaviours may be driven by escape-related motivations, at least with respect the need to find suitable defecation areas.  However, no clear link was found between IWB and anticipation of feeding, suggesting species-specific differences in how repetitive behaviours are triggered. Despite these results, lizards would still exhibit IWB with non-transparent barriers (Figure 2), suggesting that escape is not the exclusive explanation for these repetitive behaviours.

Figure 2. Results from multiple rounds of home cage observations of barrier wall interaction (minutes per day). Bearded dragons interacted more with the front barrier (that is, the barrier from which escape could occur), although still exhibited IWB (interacting with barriers) along the other 3 walls of the enclosure.

Seasonal and sex-related patterns offered further nuance. Contrary to expectations, female lizards performed IWB more during spring, while males showed consistent levels year-round. This might reflect frustrated breeding-season motivations, as females in the wild often roam widely in search of mates, a behaviour restricted in captivity. These findings emphasize the complex interplay between natural instincts and captive conditions, highlighting the importance of tailoring environments to better meet the needs of individual animals. By understanding these behaviours and using an evidence-based approach, we can deepen insights into the diverse causes of repetitive behaviours across species and thereby improve captive reptile welfare.

Note that the actual levels of IWB seen were low throughout the study, with numerous animals never performing the behaviour. There appear to be individual differences in the expression of IWB.

Citation

Denommé, M and Tattersall, GJ. 2025. Investigating the motivations of repetitive barrier interactions in Pogona vitticeps. Applied Animal Behaviour Science, 283: 106484. https://doi.org/10.1016/j.applanim.2024.106484

Learning from Tortoises

/ gtattersall

Our paper on red-footed tortoise reversal learning is now in press! This study represents the efforts of Justin Bridgeman during his honours thesis examining behaviour flexibility and cognition in tortoises. Here is a link to the paper:

https://rdcu.be/bjHU7

Bridgeman, JM and Tattersall, GJ. 2019. Tortoises develop and overcome position biases in a reversal learning task. Animal Cognition. (): 1-11. 10.1007/s10071-019-01243-8

Many thanks to Dr. Miriam Richards, TAs, Tom Eles, and all the students from our animal behaviour course (2013 – 2015) who helped with all the pre-training and Y-maze familiarisation trials that pre-dated Justin’s honours research. And many thanks to all the tortoises who participated.

Tortoise approaching the stimulus (mock experiment with cell phone video)

Tortoise receiving a reward for approaching the correct stimulus.

Here are some sample videos from the supplementary material:

Tortoise in the Y-maze examines both stimuli and slowly approaches the rewarded stimulus on the left.

Tortoise late in the training approaches the rewarded stimulus without pause.

Tortoise moves according to its developed position bias, almost makes an error but corrects itself, and approaches the positive stimulus receiving the reward.