Effect of Population Density on the Growth and Reproduction in Mouse

II. Different Number of Animals in Different Space (Same Density)

Abstract

Two cages of different size, with capacities of 1: 2 in ratio were prepared, and a litter of 4 newborn ss strain of mice was reared in the smaller cage and 2 such litters in the larger cage together with their mothers. The sex ratio was kept at 2: 2 in all the three litters. The growth and the reproductive ability of the animals in the two cages were studied in comparison and the results may be summarized as follows:
Growth: No difference was apparent in the two cages.
Age of the first conception of female mice: The female inmates of the smaller cage attained the age somewhat earlier.
Age of descent of testis: No difference observed.
Reproductive ability: The litter produced in the smaller cage tended to be somewhat larger in size, total weight and the birth weight of its members.