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Journal of the Australian Mammal Society
RESEARCH ARTICLE

Effects of nest use, huddling, and torpor on thermal energetics of eastern pygmy-possums

Sae Namekata A and Fritz Geiser A B
+ Author Affiliations
- Author Affiliations

A Centre for Behavioural Physiology and Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia.

B Corresponding author. Email: fgeiser@une.edu.au

Australian Mammalogy 31(1) 31-34 https://doi.org/10.1071/AM08114
Submitted: 18 October 2008  Accepted: 8 December 2008   Published: 7 April 2009

Abstract

Eastern pygmy-possums (Cercartetus nanus) are known to be conservative with energy use probably because they rely on food that varies in availability. We quantified how nest use, huddling, and torpor contribute to a reduction of energy expenditure in C. nanus during mild cold exposure. In comparison to normothermic resting C. nanus at the same ambient temperature, nest use reduced energy expenditure on average by ~17%, huddling as a pair in a nest by ~50%, whereas torpor, which was employed by all seven individuals, lowered energy expenditure by >95%. Our study shows that while all energy-conserving strategies employed by these possums can contribute significantly to reducing energy expenditure, torpor is by far the most effective because it not only reduces thermoregulatory energy costs, but also energy expenditure required for maintenance processes.


Acknowledgements

We thank Mike Fleming, Gerhard Körtner, and Simon Ward for constructive comments on the manuscript, and the Australian Research Council for financial support.


References

Bladon, R. V. , Dickman, C. R. , and Hume, I. D. (2002). Effects of habitat fragmentation on the demography, movements and social organization of the eastern pygmy-possum (Cercartetus nanus) in northern New South Wales. Wildlife Research 29, 105–116.
Crossref | GoogleScholarGoogle Scholar | Geiser F. , and Körtner G. (2004). Thermal biology, energetics and torpor in the possums and gliders. In ‘The Biology of Australian Possums and Gliders’. (Eds R. L Goldingay and S. M. Jackson.) pp. 186–198. (Surrey Beatty: Sydney.)

Harris, J. M. (2008). Cercartetus nanus (Diprotodontia: Burramyidae). Mammalian Species 815, 1–10.
Crossref | GoogleScholarGoogle Scholar | Ward S. J. , and Turner V. (2008). Eastern pygmy-possum, Cercartetus nanus. In ‘The Mammals of Australia’. (Eds S. Van Dyck and R. Strahan.) pp. 219–221. (Reed New Holland: Sydney.)

Westman W. , and Geiser F. (2004). Captive breeding, growth, and development of thermoregulation in the eastern pygmy-possum (Cercartetus nanus). In ‘The Biology of Australian Possums and Gliders’. (Eds R. L Goldingay and S. M. Jackson.) pp. 222–229. (Surrey Beatty: Sydney.)