Fig. 4. Graphs of the integrated EMG activity divided by change in pitch (mean ± s.e.m.) in the diaphragmaticus, ischiopubis and rectus abdominis muscles for each alligator during a dive under three conditions; with no weight added to the animal (gray bars), with weight equaling 2.5% of the animal's body mass under the jaw (white bars), and with weight equaling 2.5% of the animal's body mass on the base of the tail (black bars). Numbers 1–5 indicate the alligator that was used, followed by a L or R, which indicates if the muscle on the left or right side, respectively, was used; ^* significant treatment effect when comparing head weighted to tail weighted dives (P0.05); significant treatment effect when comparing dives where no weighted was added to tail weighted dives (P0.05). The values for integrated EMG activity divided by the change in pitch should not be compared between animals or muscles because of differences in electrodes, placement of electrodes, and individual muscle activity.