Effect of water restriction on oxygen uptake, evaporative water loss and body temperature of the rock hyrax

Summary

• 1. Evaporative water loss, O₂-consumption and body temperature were measured in three rock hyraxes under control and restricted water intake conditions.

• 2. Water turnover rate was 61±6 ml·kg^−0.82· 24 h⁻¹ during control experiments and 37±6 ml· kg^−0.82·24 h⁻¹ during water restriction.

• 3. Water restriction reduced O₂-consumption below ambient temperatures (T _a) of 28 and above 33°C; there was no effect within the thermoneutral zone. Between 12 and 27°C total evaporative heat loss decreased from 0.41±0.05 W·kg⁻¹ during control experiments to 0.34±0.04 W·kg⁻¹ during water restriction. Between 39 and 41°C evaporative heat loss increased to 1.61 W·kg⁻¹ during ad libitum and 0.72 W·kg⁻¹ during restricted water availability.

• 4. During control experiments body temperature ranged between 37 and 40°C asT _a was changed between 12 and 38°C. During water restriction the animals became hypothermic below and hyperthermic above aT _a of 27°C.