Relationship between body mass and drinking water consumption in black rats, Rattus rattus

Abstract

I investigated drinking water consumption in 19 captive black rats, Rattus rattus, in cages. The relationship between body weight (X) in grams and daily water consumption (Y) in milliliters was Y = 9.58 + 0.074X (r = 0.61), and that between body weight (X) and mean daily water consumption per 100 g body weight (Y) was Y = 28.3 - 0.061X (r = 0.55). The mean daily water consumption was 18.9 ± 5.8 ml, and the mean body weight was 125.9 ± 47.8 g. These results show that smaller rats require less drinking water than larger ones, but require more water per unit of body weight than larger ones.