[Water intake and urinary output in rhesus (Macaca mulatta) and cynomolgus monkeys (Macaca fascicularis)]

Water intake (drinking water and water from food) and urinary output in rhesus (Macaca mulatta) and cynomolgus monkey (M. fascicularis) watered ad libitum in individual cage were examined with 52 animals. The animal room was maintained at 25 +/- 2 degrees C and 55 +/- 10% with relative humidity, being lit at 12 hours interval. Water intake was found in wide variation between individuals, and about 20% of the monkeys were recognized as polydipsia without another abnormal behavior. No significant variation was found between daily water intake, but periodical (or seasonal) variation was observed in polydipsic monkey. Urinary output changed accordingly with water intake. Rate of the urinary output to the water intake was 76% in male rhesus, 59% in male cynomolgus and 49% in female cynomolgus. The rate was higher in the polydipsia than in the normal monkey. Diurnal patterns of water drinking and urinary output indicated that the monkeys were mostly active during the hours of lighting. Some effects of experimental procedure were observed on drinking and voiding in cynomolgus monkeys while no effect on rhesus monkeys. Prandial drinking was observed in monkeys as was reported on other laboratory animals such as rats.