Fig. 6. Head angle changes in an anchored J-loop take-off. Head angle is the angle between the head axis and the horizon in lateral view. Intervals are 125 ms. (A) Head angle vs position. Head angles are represented by the angle of the black bars drawn at successive head positions, labeled `1' through `8'. Position 1 represents the snake just prior to the first upward movement. (B) Head angle vs time. The head angle starts at 18° and begins to increase at about position 4, when the snake reaches the apex of the jump. At position 8, the head angle is 40°, aligned approximately 10-20° above the trajectory path in the post-take-off ballistic dive. Mass=53 g, SVL=75 cm.