Is nest building an important component of thermoregulatory behaviour in the pouched mouse (Saccostomus campestris)?

The thermoregulatory significance of nest building in Saccostomus campestris was investigated by examining the effect of temperature and photoperiod on the size and thermal conductance of nests built within artificial burrows by pouched mice from four localities in southern Africa that experience contrasting thermal conditions. There was no correlation between the amount of nesting material used and the thermal conductance of nests, which indicates that nest size was not a reliable measure of nest quality. For this reason, the significant interactive effect of sex and locality on the quantity of nesting material used, and the significantly larger nests built by wild-caught animals, appear to be unrelated to differences in nesting ability, particularly as there were no similar differences in the thermal conductance of nests between these groups. Several animals blocked the entrance to their artificial burrows and caused a significant reduction in the rate of heat loss from nests therein. However, heat conservation may not have been the primary function of plugging burrow entrances because this did not occur more frequently at lower temperatures and was not more common among animals from cooler localities. Instead, animals that sealed the entrance to their burrows were found to hoard significantly more food than animals that left the entrance open, which suggests that burrows may have been blocked to prevent the potential theft of stored food. Despite substantial variability in both the size and thermal conductance of nests built throughout the present study, there was no significant effect of temperature, photoperiod, or locality on these characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)