Body temperature patterns and rhythmicity in free-ranging subterranean damaraland mole-rats, fukomys damarensis

Abstract

Body temperature (T b) is an important physiological component that affects endotherms from the cellular to whole organism level, but measurements of T b in the field have been noticeably skewed towards heterothermic species and seasonal comparisons are largely lacking. Thus, we investigated patterns of T b patterns in a homeothermic, free-ranging small mammal, the Damaraland mole-rat (Fukomys damarensis) during both the summer and winter. Variation in T b was significantly greater during winter than summer, and greater among males than females. Interestingly, body mass had only a small effect on variation in T b and there was no consistent pattern relating ambient temperature to variation in T b. Generally speaking, it appears that variation in T b patterns varies between seasons in much the same way as in heterothermic species, just to a lesser degree. Both cosinor analysis and Fast Fourier Transform analysis revealed substantial individual variation in T b rhythms, even within a single colony. Some individuals had no T b rhythms, while others appeared to exhibit multiple rhythms. These data corroborate previous laboratory work showing multiplicity of rhythms in mole-rats and suggest the variation seen in the laboratory is a true indicator of the variation seen in the wild. © 2011 Streicher et al.