Caloric balancing and sucrose intake of hamsters and gerbils

In Experiment 1, hamsters and gerbils were randomly assigned to groups that were given a choice between pairs of sucrose solutions differing in concentration. The groups consisted of a control along with the following pairs: 2% and 6%; 2% and 8%; 2% and 12%; 2% and 18%; 6% and 8%; 6% and 12%; 6% and 18%; 12% and 18%. They were tested for 15 days, and the results indicated that the animals drank more from the cylinder containing the higher concentration. The principle of "least consummatory effort" appeared to be substantiated by these results. In Experiment 2, other hamsters and gerbils were randomly assigned to one of six groups receiving either 0.5%, 2%, 6%, 10%, 14%, or 18% sucrose solution. Analysis of their intake of sucrose and Purina Lab Chow indicated that their total caloric intake was relatively constant, reflecting the fact that an increase of consumption of the solutes in the sucrose solution reduced their intake of the stock diet. The results from both experiments indicated that although the caloric intake of hamsters relative to body weight was greater than that of gerbils, the proportion of total calories taken from sucrose was greater for the latter than for the former.