Fig. 4. Trajectory and glide angle summary plots. Fourteen trajectories, each from a different snake, are shown. (A) Side view of trajectories. Data are unsmoothed 3-D coordinates sampled at 30 Hz, rotated about the average heading angle prior to plotting. The gray shading represents the range of trajectory space of the trials. Trajectories are similar in the first 5 m of vertical drop and then diverge, with the snakes shallowing at different rates. (B) Pooled glide angle through time. Each box represents the standard quartiles of the pooled distribution of all 14 trajectories at each time interval. Error bars represent 10th and 90th percentiles, respectively. The dotted line represents the glide angle of a theoretical projectile launched with an initial horizontal velocity of 1.7 m s^-1. For the snakes, glide angle began near zero, increased rapidly and deviated from the theoretical projectile early, approximately where aerial undulation began.