1Duke Lemur Center, Duke University, 2Department of Biology, Duke University
Saturday 4:15-4:30, 200ABC
The nocturnal dwarf lemurs of Madagascar hibernate between 3-7 months a year, during the period when high quality resources are in short supply. The triggering stimuli have yet to be identified, though, along with daylength, there are indications that thyroid levels, fat stores, and temperature all play a role. Another aspect of the timing of hibernation, i.e., the time of day when the first hibernation bout occurs, has yet to be documented. It makes energetic sense for hibernation to commence after the daily activity and prior to the individual’s resting phase, as then the animal can take advantage of the lower nocturnal temperatures to commence its extended torpor. In order to examine this, we report the timing of hibernation bouts in 10 dwarf lemurs belonging to two sympatric species (3 Cheirogaleus sibreei and 7 C. crossleyi) from Tsinjoarivo forest, a high-altitude forest in central-eastern Madagascar. Hibernation bouts were identified by a drop in skin temperature approximating ambient temperature. We employed circular statistics for data analysis and found significant differences, with concentration of hibernation bouts between 22:00 and 4:00 (Rao’ Spacing Test, p=<0.01) supporting our prediction. Moreover, individuals who experienced hibernation bouts while occupying nests (which are less insulated than tree holes or underground hibernacula) generally began arousals in concordance with peaks of ambient temperature, i.e., noon or early afternoon. Obviously, more research is needed to unveil all of the factors involved in the timing of hibernation.
Margot Marsh Biodiversity Foundation, CI/Primate Action Fund, Primate Conservation Incorporated, Duke Lemur Center