Relationship between cognitive and thermoregulatory performance in the common wall lizard.

Behavioural thermoregulation is critical for reptiles, because it allows them to maintain their body temperatures within a range that optimizes physiological functions. Behavioural thermoregulation requires sensing, processing, and retaining information on the thermal environment, potentially involving several cognitive processes. Surprisingly, the relationship between cognitive performance and thermoregulatory behaviour and accuracy has hitherto remained virtually unstudied. Here we examined whether enhanced spatial cognition is correlated with more efficient thermoregulation, while also taking into account the possible confounding role of personality. To do that, we first assessed the spatial cognitive abilities of male common wall lizards in two different spatial learning tasks, as well as three personality traits (boldness, explorativeness, and sociability). We then recorded lizards' preferred body temperature range in a thermal gradient. We assessed the lizards' thermoregulatory performance by recording their body surface temperatures and heat source use in a large enclosure with different types of heat sources (lamps, heating stones, thermal mats), mimicking a spatiotemporally heterogeneous thermal environment. We found that individuals that performed well in the spatial cognition tests switched more often between different heat sources and tended to use them more evenly, but maintained lower overall body temperatures and tended to thermoregulate less accurately than their slow learning conspecifics. Social, shy, and more explorative lizards were more often observed near activated heat sources than lizards with opposite personalities, but personality profiles did not affect body temperature or thermoregulatory accuracy. Overall, spatial cognition and personality may play a role in better exploiting the thermal heterogeneity of the environment, but interestingly this did not translate into more accurate thermoregulation.