Diet, activity, and body temperature patterns of ground pangolins in a semi-arid environment

Panaino, Wendy
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Climate change is threatening biodiversity globally, with the effects already apparent across various ecosystems. Increases in air temperatures and greater variability in precipitation will reduce primary productivity, with profound effects for arid areas. Climate change affects animals directly by imposing greater heat loads and indirectly by altering the availability of their resources. Temminck’s ground pangolin (Smutsia temminckii) is a predominantly nocturnal, myrmecophagous (ant-and termite-eating) mammal that inhabits parts of eastern and southern Africa, including the hot and dry southern Kalahari. Studying the responses of pangolins to fluctuations in climate and food availability in a hot and dry environment provides an analogue for the conditions likely to become prevalent elsewhere across the pangolin distribution with climate change. I investigated the behavioural and physiological responses of six pangolins at Tswalu Kalahari Reserve for two years in response to fluctuations in climate and food availability. Each pangolin was fitted with a VHF tracking transmitter and a miniature temperature-sensitive data logger, which recorded core body temperature every 5 minutes. Low and late rainfall during the first year of the study, and the year before that, resulted in lower grass cover and prey abundance compared to in the second year. Pangolins responded to food scarcity by shifting their diet, which was normally dominated by Crematogaster ants, to include more Anoplolepis ants and Trinervitermes termites. Despite shifting their diet, pangolins experienced energy deficits, particularly during winter when prey was least available. The energy deficits resulted in lower than normal 24h minimum body temperatures when prey resources were scarce. When 24h minimum body temperature was low, which was more likely to occur during winter, pangolins emerged from their burrows earlier during the day and shortened their activity period compared to in summer, presumably to offset the metabolic costs of maintaining constant high body temperatures at night. Although the physiological and behavioural plasticity exhibited by the pangolins allowed them to cope with fluctuations in food availability, the extent to which this plasticity will buffer pangolins and other myrmecophages to climate change-induced reductions in food availability in the future is unclear
A thesis submitted in fulfilment of the requirements for the degree Doctor of Philosophy in Animal, Plant, and Environmental Sciences in the Faculty of Science, University of the Witwatersrand, 2021