Fig. 5. L4/ZA index as a control for general growth of the skeleton over time not related to reproduction. Means (± s.e.m.) for each of the 5-week blocks of the 50-week study are plotted on the x-axis. Baseline corresponds to the 5-week period prior to colony separation; the dotted line indicates the time of colony separation, and the remaining data blocks correspond to 1–45 weeks after removal from reproductive suppression. Paired females (N=2) exhibited greater L4/ZA indices over the course of the study than paired males (N=2) or controls (N=2), P<0.01 (as noted by asterisks). Data from cohorts CC1 and CC2 are included.