RADIOTELEMETRIC STUDIES ON BODY-TEMPERATURE IN MARMOSETS (CALLITHRIX-JACCHUS)

A newly developed telemetry system was used to study deep body temperature (BT) of two adult male common marmosets (Callithrix jacchus). The BT-curves of both monkeys showed a similar clear circadian rhythm with a range up to 3.5 °C. At environmental temperature of 28 °C (ET) the BT of the monkeys varied in the daytime dependent on their spontaneous activity, with little individual differences between 37.5 °C and 39.3 °C; at night the BT of the remarkaby deeply-sleeping animals decreased to an average at 35.8 °C. Elevating ET up to 30 °C effected an increase of BT by 0.6 °C, both during day and night. On the contrary, reducing ET to 24 °C the BT increased only at night, by 0.2 °C at ad libitum food intake and 1.0 °C at fasting. Measurements of BT by inserted rectal thermometer caused, compared with telemetry, an average at 0.4 °C higher values. © 1990 Dr. Dietrich Steinkopff Verlag.