One would assume that pregnant and lactating females require more water than non-pregnant females. One might also assume that juveniles require different amounts of water and food than adults. Juveniles have less dense pelage than adults, and probably are affected more by their immediate environment because of their relatively poor insulation. Juveniles might also be in an unfavorable situation insofar as water conservation is concerned, because they are actively growing, and in most cases, acquiring new pelage; it is well known that these are times of stress for the individual. TABLE 10--Weights of Mice at Start and Finish of Experiments, Showing Changes in Weight and Mean Weights, and Means of Changes in Weight (mean delta). ======================================================================== _Peromyscus truei truei_ ----+---------------------+----------------------+---------------------- | Lab Chow | Hog Chow | Corn +------+------+-------+-------+------+-------+-------+------+------- No. |Start | End |[Delta]| Start | End |[Delta]| Start | End |[Delta] ----+------+------+-------+-------+------+-------+-------+------+------- 1 | 31.0 | 31.3 | 0.3 | 31.3 | 32.3 | 1.0 | 32.3 | 29.0 | 3.3 5 | 31.1 | 30.5 | 0.6 | 30.5 | 32.8 | 2.3 | 32.8 | 28.7 | 4.1 6 | 27.6 | 27.1 | 0.5 | 27.1 | 29.5 | 2.4 | 29.5 | 27.3 | 2.2 7 | 28.0 | 26.3 | 1.7 | 26.3 | 27.5 | 1.2 | 27.5 | 22.2 | 5.3 13 | 25.8 | 30.6 | 4.8 | 30.6 | 27.0 | 3.6 | 27.0 | 22.2 | 4.8 14 | 26.9 | 30.7 | 3.8 | 30.7 | 31.4 | 0.7 | 31.4 | 27.3 | 4.1 15 | 25.4 | 29.4 | 4.0 | 29.4 | 29.8 | 0.4 | 29.8 | 24.0 | 5.8 16 | 33.0 | 32.9 | 0.1 | 32.9 | 30.5 | 2.4 | 30.5 | 26.0 | 4.5 19 | 37.6 | 38.1 | 0.5 | 38.1 | 31.8 | 6.3 | 31.8 | 22.0 | 9.8 20 | 23.5 | 25.8 | 2.3 | 25.8 | 26.2 | 0.4 | 26.2 | 22.9 | 3.1 ----+------+------+-------+-------+------+-------+-------+------+------- [=Y]| 28.9 | 30.2 | 1.8 | 30.2 | 29.8 | 2.0 | 29.8 | 25.2 | 4.7 ----+------+------+-------+-------+------+-------+-------+------+-------