Fig. 5. Schematic diagram illustrating the movement of the upper beak (opaque blue) relative to the lower beak (semi-transparent red) during the bite cycle [description follows Kear (Kear, 1994) and is redrawn from Uyeno and Kier (Uyeno and Kier, 2005)]. (A) Closed in its resting position (beaks relatively enlarged to illustrate pivot area); (B) opening; (C) fully opened; (D) closing; (E) closed with the upper beak rostrum retracted behind the lower beak rostrum. The axis around which the beaks pivot was observed to be located anywhere in the pivot area indicated in A (resting).