ABSTRACT
1. Heart rates and oxygen consumption of hibernating Citellus (= Spermophilus) lateralis were evaluated at various body temperatures. 2. Hibernation-stress animals had significantly higher heart rates as well as elevated rates of oxygen consumption at all body temperatures than did their less-stressed counterparts. 3. The higher metabolic rates of stressed animals were not due simply to their elevated heart rates. 4. It appears that unstressed animals have an energetic advantage over hibernation-stress animals.
Subject(s)
Heart Rate , Hibernation , Oxygen Consumption , Sciuridae/physiology , Stress, Physiological/physiopathology , Animals , Sciuridae/metabolism , Time FactorsABSTRACT
1. Hibernating C. lateralis were exposed to lowered ambient temperatures in order to investigate the relationship between hibernation stress and the thermoregulatory responses of the animals. 2. The least hibernation-stress squirrels exhibited a passive decline in metabolic rate until their body temperatures stabilized close to microenvironmental temperature. 3. The most stressed individuals aroused from hibernation in response to the declining ambient temperatures. 4. Intermediately stressed animals demonstrated an initial passive decline in temperature; however, at various temperatures (0.3-6.8 degrees C), this group increased their metabolic rate but did not arouse from hibernation.
Subject(s)
Cold Temperature , Hibernation , Sciuridae/physiology , Animals , Body Temperature Regulation , Oxygen Consumption , Sciuridae/metabolism , Stress, Physiological/physiopathologySubject(s)
Behavior, Animal , Hibernation , Rodentia/physiology , Sciuridae/physiology , Animals , Female , MaleABSTRACT
The frequency of arousal from periods of hibernation of Citellus lateralis, C. tridecemlineatus, and C. columbianus was demonstrated to be regulated by environmental (and therefore body) temperature over the range of 2-12 degrees C in a log-linear relationship. The slopes of the lines of regression for all three species were not significantly different from one another. Durations of the periods of hibernation for the considerably larger C. columbianus, however, were significantly longer at all levels of temperature than those for the similar-sized C. lateralis and C. tridecemlineatus. The mechanism(s) regulating the duration of the period of hibernation was considered to be concerned with some aspect of metabolism and probably the same for all three species.