ARCH 344 Chapter Notes - Chapter 4: Brown Mouse Lemur, Mouse Lemur, Cheirogaleidae
29 Jan 2017
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Ch 4: seasonal changes in body mass and activity levels. How small mammals respond to climatic and resource fluctuations. Usually refer to daily occasional periods of lethargy as torpor and hibernation for prolonged and deep periods of seasonal lethargy. Dormancy is widespread among mammals, with hibernators using hypothermia to their advantage. As small mammals have relatively higher metabolic rates than larger ones, they may enjoy greater energy savings compared with larger species because the amplitude of metabolic reduction during hibernation is greater. The presence of endogenous circannual rhythm, or exogenous factors such as temperature, resource availability, or photoperiod can set off hibernation. In tropical species, shortage of food supply or water can trigger a hypothermic response not necessarily cold temperature. Deep hibernation in small mammals is interrupted by bursts of activity and rewarming (arousals), which do not occur in large-bodied hibernators that sleep less deeply.
