Factors affecting average daily metabolic rate of the fat mouse Steatomys pratensis (Dendromurinae)

1.Euthermic Steatomys pratensis showed a circadian rhythm in body temperature (Tb) ranging 31.1-32.6 °C throughout day and 33.2-35.0 °C at night.2.Tb of torpid mice was close to ambient temperature (Ta) in the early hours of the morning, higher in late morning.3.Daily torpor lasted 5.5 to 11.6 h.4.Energy expenditure in thermoneutrality was 30.9 kJ day−1, about three times basal metabolic rate (BMR).5.For euthermic mice at Ta=20°C ADMR averaged 41.4 kJ day−1 but in torpid mice it declined to 18.2 kJ day−1, an energy saving of 56%.6.In contrast, huddling at Ta=20°C reduced energy expenditure by 18%.