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Journal of Comparative Physiology B

, Volume 168, Issue 4, pp 303–312 | Cite as

Torpor patterns in the pouched mouse (Saccostomus campestris ; Rodentia): a model animal for unpredictable environments

  • B. G. Lovegrove
  • J. Raman
ORIGINAL PAPER

Abstract

Patterns of spontaneous and induced daily torpor were measured in the Afrotropical pouched mouse (77–115 g), Saccostomus campestris, in response to photoperiod, temperature, and food deprivation, using temperature telemetry. Photoperiod had no influence on the incidence, depth, or duration of daily torpor in either males and females. Although the testis size index decreased in response to food deprivation and photoperiod by a maximum of 24%, full testis regression did not occur. Torpor bout duration was, on average, 5.3 h, independent of photoperiod and ambient temperature. Males did not enter torpor in response to food deprivation but did in response to low ambient temperature, though significantly less frequently than females. At normothermia, the body temperatures (daily minimum, mean, maximum) of males were significantly lower than those of females. Minimum body temperatures of both males and females during torpor did not fall below 20 °C at an ambient temperature of 15 °C. The patterns of torpor measured here differ from those observed in species from strongly seasonal environments. They suggest adaptation to an environment rendered unpredictable by the El Niño Southern Oscillations. As an aseasonal, opportunistic breeder capable of year-round adaptive hypothermia, the pouched mouse represents an excellent model animal for research on physiological and behavioral adaptations to unpredictable environments.

Keywords

Food Deprivation Daily Minimum Testis Size Behavioral Adaptation Size Index 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • B. G. Lovegrove
    • 1
  • J. Raman
    • 1
  1. 1.Department of Zoology and Entomology, University of Natal, Private Bag X01, Scottsville 3209, South Africa Tel.: +27 331 2605113, Fax: +27 331 2605105 e-mail: lovegrove@zoology.unp.ac.zaZA

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