Laboratory metabolism and evaporative water loss of the aardwolf, Proteles cristatus.

We examined oxygen consumption and total evaporative water loss of aardwolves (Proteles cristatus) at temperatures within and below their thermal neutral zone during both summer and winter. During summer (December), body masses of aardwolves averaged 8.1 +/- 0.7 kg (+/-1 standard deviation). Within their thermal neutral zone, oxygen consumption was 2,194 +/- 443 mL O2 h-1, or 1,058 kJ d-1. The relationship between oxygen consumption (VO2, mL O2 h-1) and ambient temperature (Ta, degree C) below the lower critical temperature was VO2 = 6,310-178 (Ta). During winter (August), aardwolves had an average mass of 7.8 +/- 0.7 kg and a basal metabolic rate of 1,844 +/- 224 mL O2 h-1, or 889 kJ d-1. Below the thermal neutral zone, VO2 = 4,308-116 (Ta). Basal metabolic rate and the slope of the line relating oxygen consumption to ambient temperature were both significantly higher in summer than in winter. Evaporative water loss increased with air temperature for both seasons but was higher in summer than winter. Wet thermal conductance was relatively constant below the thermal neutral zone, but was significantly higher in summer (0.022 +/- 0.001 mL O2 g-1 h-1 degree C-1) than in winter (0.015 +/- 0.001 mL O2 g-1 h-1 degree C-1).