Abstract Rates of oxygen consumption and respiratory water loss were studied in camels that were exposed to desert heat and water deprivation. We found that changes in body temperature are accompanied by considerable changes in respiratory water loss. Body temperature fluctuations are greatest in dehydrated camels (up to 7°C), and in these the respiratory water loss might vary from about 0.06 to 1.2 g/min. The respiratory frequency varied from about 4 to 28 min-1, while the metabolic rate varied by less than twofold. The lowest values for respiratory water loss can be explained by the exhalation of air at temperatures far below body temperature, and, in addition, removal of water vapour from the exhaled air, resulting in exhalation of air at less than 100% relative humidity.