Fig. 3. The effect of incline on forward (x) and lateral (y) displacement of a single longitudinal point over time. All graphs are of a mid-body point on the same individual moving on a 4.1 cm perch and equivalent tunnel width (8.1 cm). Twice as much time is shown for the perches (B–D) compared to the tunnel (A). The arrows in B indicate backwards slipping. A, B and C illustrate approximately two, one and two complete cycles, respectively, and D displays non-cyclic downward sliding. (A) Tunnel. (B) Uphill 90° perch. (C) Horizontal perch. (D) Downhill 90° perch.