Fig. 5. Mean values (± s.e.m) of kinematic variables. (A) Cycle duration, t_cycle. (B) Percent of time in static contact, %stat. (C) Forward displacement per cycle, x. (D) Mean forward velocity, V_x. (E) Forward velocity of crossing points, V_x,cr. The downhill data were omitted from A–C because snakes did not stop periodically. Values for the largest two tunnel widths in A, B and C are only from the single individual who performed concertina locomotion, whereas D includes values from two additional individuals that performed lateral undulation.