Figure 2.—Relationship between oxygen consumption and chamber air temperature for raccoons in summer: captive females, open circles; captive males, closed circles; trapped males, open squares. Sloping lines represent regressions of oxygen consumption on chamber air temperature, and horizontal lines, basal metabolism.
Figure 3.—Relationship between oxygen consumption and chamber air temperature for raccoons in winter: captive females, open circles; captive males, closed circles. Solid sloping line represents regression of oxygen consumption on chamber air temperature for males and females, and the horizontal line, basal metabolism for males and females.
Cmw was calculated for each season from metabolic measurements made at all air temperatures below Tlc ([Table 3]). Because evaporative water loss was not measured at temperatures below freezing, Cmd was calculated only from metabolic determinations made at air temperatures between Tlc and 0°C. There was no difference between males and females in summer for either Cmw or Cmd (mL O2·g-1·h-1·°C-1). Data for each sex were combined to give a summer average of 0.0256 ± 0.0028 for Cmw, and 0.0246 ± 0.0019 for Cmd ([Table 3]). These summer conductances were 49% higher (p<0.005) than those calculated for winter females (0.0172 ± 0.0023, and 0.0161 ± 0.0027 for Cmw and Cmd, respectively; [Table 3]). Cmw and Cmd were not different from each other in either summer or winter, which indicated that in both seasons evaporative water loss contributed very little to heat dissipation at temperatures below Tn. Comparisons of thermal conductances calculated on the basis of metabolic body size (Mellen, 1963) gave the same results.
Evaporative Water Loss