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Thermal physiology of three sympatric small mammals from southern Africa
Author(s) -
Hoole C.,
Czenze Z. J.,
Bennett N. C.,
McKechnie A. E.
Publication year - 2019
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/jzo.12613
Subject(s) - biology , sympatric speciation , mammal , thermoregulation , zoology , range (aeronautics) , ecology , shrew , basal metabolic rate , sympatry , materials science , composite material , biochemistry
Small mammals, and particularly shrews and mice, have relatively high mass‐specific metabolic rates and may be constrained to habitats where they can avoid extreme temperatures. Although their phylogeny differs, shrews and rodents often inhabit the same environments and compete for resources due to their similar body masses and dietary overlap. Our aim was to elucidate the variation in thermal parameters of sympatric species. We examined Myosorex varius , Crocidura flavescens and Mus minutoides , by measuring metabolic rate, evaporative water loss ( EWL ), body temperature ( T b ) and thermal conductance over a range of ambient temperatures ( T a ). Body temperatures of all three species remained above 32°C across the range of T a . For all species, there was no relation between T a <35°C and EWL , although EWL in C. flavescens was considerably lower compared to the other two species. Dry thermal conductance was much higher in Mu. minutoides than in either of the shrews. Resting metabolic rate of all three species declined with T a <35°C. The thermoneutral zone of My. varius was between T a = 35°C and T a = 40°C, whereas that of C. flavescens was between T a = 30°C and T a = 33°C. No discernible thermoneutral zone was evident for Mu minutoides . Our data reveal considerable variation in thermal physiology among three sympatric species of small mammal at a single site and generally conform to the plesiomorphic–apomorphic endothermy model. Differences in body size, life‐history traits and evolutionary history may all play a role in the thermoregulatory patterns of these sympatric species.