Bioenergetics and Water Requirements of the Redback Vole, Clethrionomys gapperi

The effects of temperature on food consumption, assimilation efficiency, oxygen uptake, and water requirements of the redback vole, Clethrionomys gapperi, were studied. Gross and net caloric intakes varied inversely with temperature and the relationships were geometric rather than linear. Assimilation efficiency was maximal at 25°C (78.9 per cent) and lowest at 10°C (72.2 per cent). Manometric measurements of oxygen consumption indicated a resting metabolic rate of 3.14 cc O2/g/hr, a thermoneutral zone from 25 to 28°C, and a thermal conductance of 0.255 cc O2/g/hr/°C. Water consumption increased with temperatures above and below 15°C. Minimum water requirements, including free water, food moisture, and metabolic water, were 0.64 g H2O/g/day at 15°C. These data are compared to those of other small mammals.