An infrared thermographic study of surface temperature in the euthermic woodchuck (Marmota monax)

Surface temperatures were measured in euthermic woodchucks (Marmota monax) using infrared thermography across a range of ambient temperatures from -10 degreesC to 32 degreesC. The woodchuck keeps surface temperature of the pe ripalpebral region uniformly high, while head and body surfaces change prop ortionally with ambient temperature. When ambient temperature was below 0 d egreesC, all surface temperatures increased which prevents freezing. At no point did the animals appear to be unable to regulate heat exchange. This s pecies appears to be especially well adapted to the higher temperatures it encounters in its range. Vasomotion in the feet and to a lesser extent in t he pinnae was used to regulate heat loss. At ambient temperature of 32 degr eesC, mean temperatures of nose surfaces were 0.2 degreesC and 0.3 degreesC less than ambient temperature suggesting a type of counter current cooling mechanism may be present. (C) 2001 Elsevier Science Inc. All rights reserv ed.