Food and energy intake, non-shivering thermogenesis and daily rhythm of body temperature in the bushy-tailed gerbil Sekeetamys calurus: The role of photoperiod manipulations

1. The bushy-tailed gerbil, Sekeetamys calurus, is a nocturnal rock dwelling rodent inhabiting extremely arid zones in Arabia. The daily rhythms of body temperature (T_b), the daily food, energy and water consumption as well as heat production by means of non-shivering thermogenesis (NST), were compared in individual gerbils acclimated to two different photoperiod regimes 16L : 8D (LP) and 8L : 16D (LS) at the same ambient temperature (T_a) of 28°C. 2. The daily rhythms of T_b are entrained by photoperiod. Different patterns of these rhythms were evident under the different photoperiod regimes. A higher T_b was maintained for a longer period in LP-acclimated gerbils when compared with LS-gerbils. Food, energy and water intake as well as NST were significantly higher in LS-gerbils compared with LP-gerbils. 3. These results suggest that seasonal acclimatization of thermoregulatory mechanisms in the bushytailed gerbii can be partly induced by changes in photoperiod.