Who does bask longer? A comparison between elapid and viperid snakes in the field and in experimental conditions

Temperature profoundly influences the biology of ectotherm organisms, for example reptiles, which mostly regulate their body temperature behaviorally by shuttling between heat sources and sinks. The thermal quality of the environment directly affects the amount of time that a reptile takes to keep the body temperature within the optimal range. The foraging strategy of reptiles is often correlated to the thermoregulatory strategies. Depending on their foraging strategy, carnivorous reptiles can be high-energy consumers (active foragers) or low-energy consumers (ambush foragers). Our study allowed to get insights into basking versus non-basking behaviors of (i) snakes belonging to two different families (eight viperids and four elapids) with contrasted life-styles by either field or captive observations, (ii) free-ranging snakes (n = 3245) inhabiting contrasted habitats (forest versus savannah), and (iii) captive snakes (n = 4) outside the feeding activity and during digestion phase. We observed a tendency to spend more time in thermoregulation in the viperids than in the elapids and this pattern were consistent between field and experimental observations. We suggest that the higher basking activity of viperids is correlated to their predominantly nocturnal and ambush habits compared to the diurnal and active-foraging habits of the elapids. We also observed an effect of the thermal environmental quality with the savannah species tending to bask less than forest species. As for postprandial termophily, viperids showed a longer postprandial basking time than elapids even if all the snakes in the captivity sample were fed identically in terms of prey type and relative prey mass. Conservation insights related to the observed pattern are also provided.