Figure 1.

(a(i,ii)) The stimulus protruded from a large piece of bark. R/C components were concealed from view and attached to a timber frame. Servos were positioned to generate vertical (V) and horizontal (H) motion using aluminium rods to increase range. Fishing line (0.22 mm) connected to the rods allowed tail manipulation in four stages: stage 1, vertical displacement to half-maximum extension; stage 2, vertical and horizontal displacement to half-maximum extension; stage 3, vertical and horizontal displacement to maximum extension; and stage 4, continuous motion. (a(iii)) Position–time plot for stages 1–3 flicks shown as the amplitude displacement of the tail tip from rest. (b) Test lizard's view of the arena from slightly above the lizard compartments. The stimulus was presented at (A) 1 m, at a height of 0.3 m, and (B) 3 m, elevated to 1.3 m to ensure plants in the foreground did not occlude the flicking tail.