Insights into torpor and behavioural thermoregulation of the endangered Juliana's golden mole

Abstract

AbstractThe cryptic, subterranean ways of golden moles (Chrysochloridae) hamper studies of their biology in the field. Ten species appear on the IUCN red list, but the dearth of information available for most inhibits effective conservation planning. New techniques are consequently required to further our understanding and facilitate informed conservation management decisions. We studied the endangered Juliana's golden mole Neamblysomus julianae and aimed to evaluate the feasibility of using implantable temperature sensing transmitters to remotely acquire physiological and behavioural data. We also aimed to assess potential body temperature (Tb) fluctuations in relation to ambient soil temperature (Ta) in order to assess the potential use of torpor. Hourly observations revealed that Tb was remarkably changeable, ranging from 27 to 33 °C. In several instances Tb declined during periods of low Ta. Such ‘shallow torpor’ may result in a daily energy saving of c. 20%. Behavioural thermoregulation was used during periods of high Ta by selecting cooler microclimates, while passive heating was used to raise Tb early morning when Ta was increasing. In contrast to anecdotal reports of nocturnal patterns of activity, our results suggest that activity is flexible, being primarily dependent on Ta. These results exemplify how behavioural patterns and microclimatic conditions can be examined in this and other subterranean mammal species, the results of which can be used in the urgently required conservation planning of endangered Chrysochlorid species.