Observations on the Metabolism of Arctic Ground Squirrels (Citellus Parryi) at Different Environmental Temperatures

Abstract

Summary and Conclusions. The metabolic rate of Arctic ground squirrels was determined and found to be of the same magnitude as common in mammals. Determinations during sleep at night showed a reduction of the metabolic rate to about 50 per cent of the average daytime values. The squirrels seemed to tolerate environmental temperatures from — 30° to + 40° C well; at higher temperatures they only survived limited exposure (about 1 hour at + 50° C). The metabolic rate remained fairly constant at environmental temperatures from + 10° to + 50° C; at lower temperatures their activity and metabolic rate increased. S cholander et al. (1950). In the fall, when the animals gained weight, high RQ's (from 1.0 to 1.4) were usually found the first hours after feeding, when the environmental temperature was above 0° C, and always when it was above + 20° C. At 0° C and lower, the RQ's were always “normal” (0.7 to 1.0). This effect of the environmental temperature on the metabolism which was found the first hours after feeding diminished rapidly after approximately 4 to 5 hours. In the following spring when the squirrels did not gain weight, changes in the environmental temperature did not affect their RQ.