The preputial gland as an indicator of social dominance in male mice

Preputial gland weight was assessed in dominant and subordinate male, C57BL/6J mice following 14 days of grouping under two conditions: (a) two males per cage using isolated males as controls and (b) groups of two males and one female per cage where single males cohabiting with females served as controls. Weight of this pheromone-producing gland was not affected by the presence of females. Preputial glands of dominant males, however, averaged 84 and 86% heavier than those of control males in the two experiments. Preputial glands of subordinates were significantly smaller than controls in the first experiment but not the second. Based on a comparison of weight ranges in the various treatments, it can be concluded that this gland actually grows in size during the attainment and/or maintenance of a dominant social position.