Sun-basking, a necessity not a leisure: Anthropogenic driven disturbance, changing the basking pattern of the vulnerable Indian rock python in Keoladeo National Park, India

Abstract

‘Basking’ is the most conspicuous thermoregulatory behavior in many animals that enable them to enhance physiological performance. Several terrestrial poikilothermic ectotherms have adapted to thermoregulate through basking and seek refuge in subterranean burrows in extreme climatic conditions. Particularly in reptiles, selecting appropriate activity times and postural adjustments are critical thermoregulatory mechanisms and have been recognized as a significant element in the process of behavioral thermoregulation. The present study aims to understand the behavioral adaptation, burrow use regime, and basking pattern of the Indian rock python Python molurus in Keoladeo National Park which witnesses annual weather extremes. Further, the study also investigates the effect of anthropogenic disturbance on the behavioral repertoires of the species, including the changes occurring in the pattern of emergence and retreat into the burrow and basking periods of pythons. The estimated minimum population size of python in KNP was 80 ± 10SD individuals. During the active months of November to April, a general pattern of python activity was observed wherein pythons emerged at 09h00 to 10h00, with a peak in mean basking time of 49.3 ± 18.4SD min per day during 12h00 to 13h00 following retreat at 17h00 to 18h00. Also, the emergence timings positively correlated with the sunrise timing and increasing temperature. Whereas, the retreat timings positively correlated with the sunset timing in disturbed burrows with continuous tourist visits, a significant change in the emergence, retreat and basking duration was observed. The time spent for basking significantly varied between disturbed, semi-disturbed and undisturbed burrows across different time-slots. The basking time across all the time intervals of the day around the undisturbed burrows was twofold of the time spent around disturbed burrows. The present study thus highlights the change in basking regime of Indian rock python in disturbed and undisturbed habitats in KNP, during the tourist's season of October to April each year. Keywords: Python molurus, Burrow activity, Thermoregulation, Camera trap, Ecotourism, Disturbance