LABORATORY METABOLISM AND EVAPORATIVE WATER-LOSS OF THE AARDWOLF, PROTELES CRISTATUS

We examined oxygen consumption and total evaporative water loss of aar dwolves (Proteles cristatus) at temperatures within and below their th ermal neutral zone during both summer and winter. During summer (Decem ber), body masses of aardwolves averaged 8.1 +/- 0.7 kg (+/- 1 standar d deviation). Within their thermal neutral zone, oxygen consumption wa s 2,194 +/- 443 mt O-2 h(-1), or 1,058 kJ d(-1). The relationship betw een oxygen consumption (V)over dotO(2),mL O-2 h(-1)) and ambient tempe rature (T-a, degrees C) below the lower critical temperature was (V)ov er dotO(2) = 6,310 - 178 (T-a). During winter (August), aardwolves had an average mass of 7.8 +/- 0.7 kg and a basal metabolic rate of 1,844 +/- 224 mL O-2 h(-1), or 889 kJ d(-1). Below the thermal neutral zone , (V)over dotO(2), = 4,308 - 116 (T-a). Basal metabolic rate and the s lope of the line relating oxygen consumption to ambient temperature we re both significantly higher in summer than in winter. Evaporative wat er loss increased with air temperature for both seasons but was higher in summer than winter. Wet thermal conductance was relatively constan t below the thermal neutral zone, but was significantly higher in summ er (0.022 +/- 0.001 mL O-2 g(-1) h(-1) degrees C-1) than in winter (0. 015 +/- 0.001 mL, O-2 g(-1) h(-1) degrees C-1).