FOOD AND ENERGY-INTAKE, NONSHIVERING THERMOGENESIS AND DAILY RHYTHM OF BODY-TEMPERATURE IN THE BUSHY-TAILED GERBIL SEKEETAMYS CALURUS - THEROLE OF PHOTOPERIOD MANIPULATIONS

The bushy-tailed gerbil, Sekeetamys calurus, is a nocturnal rock dwell ing rodent inhabiting extremely arid zones in Arabia. The daily rhythm s of body temperature (T-b), the daily food, energy and water consumpt ion as well as heat production by means of non-shivering thermogenesis (NST), were compared in individual gerbils acclimated to two differen t photoperiod regimes 16L:8D (LP) and 8L:16D (LS) at the same ambient temperature (T-a) of 28 degrees C. 2. The daily rhythms of T-b are ent rained by photoperiod. Different patterns of these rhythms were eviden t under the different photoperiod regimes. A higher T-b was maintained for a longer period in LP-acclimated gerbils when compared with LS-ge rbils. Food, energy and water intake as well as NST were significantly higher in LS-gerbils compared with LP-gerbils. 3. These results sugge st that seasonal acclimatization of thermoregulatory mechanisms in the bushy-tailed gerbil can be partly induced by changes in photoperiod.