Comparison of surface temperature in 13-lined ground squirrel (Spermophilus tridecimlineatus) and yellow-bellied marmot (Marmota flaviventris) during arousal from hibernation

摘要

Surface temperatures (T-s) of eight 13-lined ground squirrels and seven yellow-bellied marmots were measured during arousal from hibernation using infrared thermography (IRT) and recorded on videotape. Animals aroused normally in 5 degreesC cold rooms. Body temperatures were recorded during arousal using both cheek pouch and interscapular temperature probes. Warming rate in arousal was exponential. Mean mass specific warming rates show the squirrels warm faster (69.76 degreesC/h/kg) than the marmots (4.49 degreesC/h/kg). Surface temperatures (T-s) for 11 regions were measured every few minutes during arousal. The smaller ground squirrel shows the ability to perfuse distal regions without compromising rise in deep body temperature (T-b). All squirrel T-s's remained low as T-b rose to 18 degreesC, at which point, eyes opened, squirrels became more active and all T-s's rose parallel to T-b. Marmot T-s remained low as T-b rose initially. Each man-not showed a plateau phase where T-b remained constant (mean T-b 20.3 +/- 1.0 degreesC, duration 9.4 +/- 4.1 min) during which time all T-s's rose, and then remained relatively constant as T-b again began to rise. An anterior to posterior T-s gradient was evident in the ground squirrel, both body and feet. This gradient was only evident in the feet of the marmots. (C) 2004 Elsevier Inc. All rights reserved.