Daily torpor during the active phase in free-ranging rock elephant shrews (Elephantulus myurus)

Authors

  • Nomakwezi Mzilikazi,

    Corresponding author
    1. School of Biological and Conservation Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, South Africa
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  • Barry G. Lovegrove

    1. School of Biological and Conservation Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, South Africa
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All correspondence to present address: N. Mzilikazi, Department of Zoology, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth, 6031, South Africa. E-mail: nomakwezi.mzilikazi@nmmu.ac.za

Abstract

In highly seasonal environments animals that use daily torpor usually do so during the rest phase. In subtropical and tropical environments, however, daily torpor may not necessarily be confined to the animals' rest phase. Animals may display torpor during the active phase. We investigated the daily rhythms and seasonal rhythms of body temperature (Tb) in normothermic and torpid free-ranging rock elephant shrews Elephantulus myurus at Weenen Game Reserve, KwaZulu-Natal, South Africa. Tbs were recorded using miniature dataloggers from May 2001 to May 2002. Daily patterns of Tb in normothermic E. myurus suggested polyphasic Tb patterns that nevertheless suggested a rest phase that was coincident with the daytime. When the elephant shrews used torpor, the lowest Tbs were observed during the night-time, such that torpor was used during the coldest part of the night and arousal was associated with the 3-h period around sunrise. We suggest that the principal benefit of a flexible daily rhythm of Tb was that it facilitated arousal by passive exogenous heating using ambient temperature cycles.

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