Effect of Temperature on the Heart and Ventilation Rates in the Agamid Lizard Uromastyx microlipes (the Dhubb) in the Central Region of Saudi Arabia

The effect of body warming and cooling on the heart andbreathing rates has been studied in the agamid lizard Uromastyx mi-crolipes. Electrocardiograph (ECG) of Uromastyx microlipes consistsof P, QRS, and T components similar to those in mammals. Heart rateincreases with body temperature. During warming the heart rateranged from 7-134 beat/min, while during cooling ranged from 2-73beat/min. The mean of heart rate during warming and cooling was notsignificantly different except at body temperatures of 20ºC and 35ºC.In two lizards heart rate was higher during warming than cooling forall temperatures. Both breathing types (thoracic and buccal) increasedin frequency with body temperature. The range of thoracic breathingrates during both warming and cooling was 0-20 breath/min. Buccalbreathing rate was 0-24 breath/min during warming, and 0-26 breath/min during cooling.