1. 1. At sea level the core temperatures of the alpaca (Lama pacos) and llama (Lama glama), recorded continuously by radiotelemetry, were within the ranges of 37·9-38·3°C and 38·l-38·6°C respectively. These ranges were unaltered after 6 days of water deprivation. 2. 2. At high altitude (4·1 km) the ranges were very similar (37·6-38·2°C and 37·2-38·0°C respectively) Six days of water deprivation was without effect on the core temperature range of the alpaca at this altitude. 3. 3. The core temperature of the two vicunas (Lama vicugna) at high altitude was greater than those of the other species (36·0-37·9°C and 37·4-39·l°C). 4. 4. Just before parturition, the core temperature of a pregnant alpaca at high altitude was elevated by about 1°C. © 1975.