Ca. Stewart et Pa. Mcclure, DIURNAL-VARIATION IN THERMAL AND METABOLIC PARAMETERS OF THE GOLDEN-HAMSTER (MESOCRICETUS-AURATUS), Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology, 163(3), 1993, pp. 234-238
The purpose of this study is to examine diurnal variation in several t
hermal and metabolic parameters of the golden hamster, Mesocricetus au
ratus. Metabolic rate, core temperature, and evaporative water loss we
re measured during night and day at several ambient temperatures. Wet
minimal thermal conductance, dry minimal thermal conductance, basal me
tabolic rate, minimal net heat production and the lower critical tempe
rature difference were estimated from these measurements. Wet and dry
minimal thermal conductance, evaporative water loss, core temperature,
basal metabolic rate, and lower critical temperature difference were
greater during the active phase than during the resting phase. The diu
rnal variation in wet minimal thermal conductance was much smaller tha
n that predicted from published allometric equations. The diurnal vari
ation in wet minimal thermal conductance was 9% of the 24-h mean. The
diurnal variation in dry minimal thermal conductance was 26% of the 24
-h mean. The higher active-phase core temperature and basal metabolic
rate may function to enhance peak metabolic performance during the act
ive phase. The lower resting phase metabolism and core temperature may
reduce energetic costs. The greater active-phase lower critical tempe
rature difference may be a result of the greater active-phase basal me
tabolic rate. Diurnal variation in minimal thermal conductance may be
caused by changes in peripheral circulation.