The effects of ambient temperature on the body temperature rhythm of rats, hamsters, gerbils, and tree shrews

The daily rhythm of body temperature of male rats, Syrian hamsters, fat-tailed gerbils, and tree shrews was studied by telemetry. All animals were maintained for five days at each of four ambient temperatures (14, 20, 28, and 32 degrees C). The amplitude of the body temperature rhythm of tree shrews was Found to decrease as ambient temperature increased. The amplitude of the temperature rhythm of rats was found ro remain constant at 14, 20, and 26 degrees C but to be slightly reduced at 32 degrees C. No significant effect of ambient temperature was found on the amplitude of the body temperature rhythm of Syrian hamsters and fat-tailed gerbils. Reductions in rhythm amplitude were due mostly to the curtailment of the daily fall in body temperature with no alteration in the daily peak. (C) 1997 Elsevier Science Ltd. All rights reserved.