E.M. Samara1, K. Abdoun1, O. AL-Tayib2, A.B. Okab1 and A.A. AL-Haidary1
1Department of Animal Production, College of Food and Agriculture Sciences,
King Saud University, PO Box 2460, Riyadh 11451, Kingdom of Saudi Arabia
2Eng. A.B. Research Chair Growth Factors and Bone Regeneration, College of Dentistry,
King Saud University, Riyadh, Kingdom of Saudi Arabia
Current study was conducted to estimate the anatomical proximity of the tympanic membrane to the hypothalamus, and to record the circadian rhythm of dromedary camel's tympanic membrane temperature (Tty) under natural summer photoperiod. The anatomical features of dromedary camel's ear canal and tympanic membrane had been identified using sagittal, transverse, and frontal head sections, where it revealed unique anatomical features which differ from that of other farm animals. Moreover, it was evident that the tympanic membrane of dromedary camels can provide a non-invasive access to the hypothalamus. Our result demonstrated the presence of a clear monophasic circadian rhythm of camels' Tty with a rhythm oscillation of 1.15°C. These findings indicate that camels, similar to other species of farm animals, are homeothermic animals, capable of maintaining near constant body temperature under their natural environmental conditions. Circadian rhythm of Tty in camels might reflect an endogenous rhythm rather than a reaction to the environmental ambient temperature.
Key words: Body temperature, camel, circadian rhythm, entrainment, homeothermy, thermistor, thermoregulation, tympanic membrane