Sexual differences in over-winter torpor patterns of Richardson's ground squirrels in natural hibernacula.

摘要: Over-winter torpor patterns of Richardson's ground squirrels hibernating in southern Alberta were monitored with temperature-sensitive radiocollars to determine if these differed between males and females a manner related the greater costs mating effort by than females. The hibernation season (from immergence emergence) was composed three periods: post-immergence euthermy, heterothermy, pre-emergence euthermy. shorter for juveniles adults both among (< 150 versus 234 days) (185 231 days), reflection later into juveniles. However, regardless absolute duration hibernation, heterothermy accounted smaller proportion (93±5%) (98±1%) and, within heterothermal period, had bouts longer inter-torpor arousals. Overall, spent (85±6%) (92±1%). This sexual difference largely attributable preemergence euthermy Males terminated January February, when hibernacula at their coldest, then remained euthermic 8.8 days (range 0.5-25.0 before emergence. In contrast, March, hibernaculum temperatures increasing, only 1.1 0.5-2.0 lost less mass per day during (7.0 9.3 g/day). hibernated similar depths (56 cm), but larger chambers (18 16 cm3/g). Many males, no females, cached seeds hibernaculum. met thermogenesis from combination fat reserves food caches, whereas relied solely on fat. Access caches permitted terminate several weeks advance emergence, which time they recouped developed sperm preparation forthcoming season.