Journal of Comparative Physiology B

, Volume 183, Issue 8, pp 1113–1122

Some like it cold: summer torpor by freetail bats in the Australian arid zone

  • Artiom Bondarenco
  • Gerhard Körtner
  • Fritz Geiser
Original Paper

Abstract

Bats are among the most successful groups of Australian arid-zone mammals and, therefore, must cope with pronounced seasonal fluctuations in ambient temperature (Ta), food availability and unpredictable weather patterns. As knowledge about the energy conserving strategies in desert bats is scant, we used temperature-telemetry to quantify the thermal physiology of tree-roosting inland freetail bats (Mormopterus species 3, 8.5 g, n = 8) at Sturt National Park over two summers (2010–2012), when Ta was high and insects were relatively abundant. Torpor use and activity were affected by Ta. Bats remained normothermic on the warmest days; they employed one “morning” torpor bout on most days and typically exhibited two torpor bouts on the coolest days. Overall, animals employed torpor on 67.9 % of bat-days and torpor bout duration ranged from 0.5 to 39.3 h. At any given Ta, torpor bouts were longer in Mormopterus than in bats from temperate and subtropical habitats. Furthermore, unlike bats from other climatic regions that used only partial passive rewarming, Mormopterus aroused from torpor using either almost entirely passive (68.9 % of all arousals) or active rewarming (31.1 %). We provide the first quantitative data on torpor in a free-ranging arid-zone molossid during summer. They demonstrate that this desert bat uses torpor extensively in summer and often rewarms passively from torpor to maximise energy and water conservation.

Keywords

Bat Desert Mormopterus Torpor Passive rewarming Insect abundance 

Abbreviations

Ta

Ambient temperature

Tskin

Skin temperature

Tb

Body temperature

TBD

Torpor bout duration

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Artiom Bondarenco
    • 1
  • Gerhard Körtner
    • 1
  • Fritz Geiser
    • 1
  1. 1.Centre for Behavioural and Physiological Ecology, ZoologyUniversity of New EnglandArmidaleAustralia

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