SEASONAL-VARIATION IN RESTING METABOLIC-RATE AND BODY-TEMPERATURE OF STREAKED TENRECS, HEMICENTETES NIGRICEPS AND H-SEMISPINOSUS (INSECTIVORA, TENRECIDAE)

Annual variations in resting metabolic rate (RMR) and body temperature (Tb) were measured in the streaked tenrecs Hemicentetes nigiceps and H. semispinosus. RMR in non-reproducing, non-torpid adults was lower than predicted by the Kleiber (1961) curve, supporting Genoud's (1990) hypothesis on BMR in hibernating mammals. Both species demonstrated a reduction in RMR and Tb during the austral winter and these changes were independent of body mass. H. semispinosus frequently roused from torpor to forage whereas H. nigriceps remained dormant throughout the winter. This contrast in activity patterns may result from altitudinal differences in species distributions. H. nigriceps may be an obligate hibernator whereas H. semispinosus, living at lower, warmer altitudes, may be a facultative-hibernator. It is proposed that the ability of H. semispinosus to remain active during favourable climatic conditions allows winter breeding and increases annual reproductive output.