HIBERNATION OF THE THIRTEEN-LINED GROUND SQUIRREL,CITELLUS TRIDECEMLINEATUS(MITCHILL). III. THE RISE IN RESPIRATION, HEART BEAT AND TEMPERATURE IN WAKING FROM HIBERNATION

Abstract

The increase in respiration, heart beat and temperature as shown in graphs is very gradual at first in waking in a cold room of 0° to 8° C., whereas in a warm room of near 30° C. the process is more rapid from the first. In both cases there is a very rapid rise of all near or at the time of the opening of the eyes when the respiration rate commonly ranged between 100 and 200 a minute, and the heart beat rate usually ranged between 300 and 400 a minute, and the temperature between 20° and 34° C. The anterior part of the animal wakes more rapidly than the posterior regions, and œsophageal and food pouch temperatures indicate the increase in metabolism more accurately than deep rectal or anal temperatures. There is a general correlation between the curves of rise of respiration, heart beat and temperature. In the production of waking heart beat appears to be somewhat more effective than respiration. Waking may be induced by stimulation but its rate is not proportional to the duration or intensity of the stimulation applied, except in the case of a surrounding high temperature. Transference to a room of about 0° C. appears to stimulate waking in some but not in all torpid ground squirrels. This temperature does not prevent hibernation.