Fig. 5.

Displacement (A–C), velocity (D–F) and acceleration (G–I, black lines) of the nose calculated for the X (left column), Y (middle column) and Z (right column) axes of the E-frame during a feeding strike. For the x-axis, positive is towards the front of the animal. For the y-axis, positive is towards the animal’s left. For the z-axis, positive is up. Accelerations calculated for the X and Y axes in the planes of the left (red lines) and right (green lines) utricles, i.e., the left and right U-frames, are also shown in G and H. Data for the left OL are the same as those shown in Figures 7A and 6C. The accelerations in the E-frame do not include any contribution from gravity. The differences between the E-frame accelerations and the left and right U frame accelerations are largely due to gravity components in the U-frame resulting from the orientation of the OL within the head, the orientation of the head within the E-frame, and the Z-axis acceleration of the head in the E-frame. For the X-axis, the accelerations are reduced by the 24° downward pitch of the OL (see Figure 2), which reduces the accelerations produced by forward motion of the head in the E-frame and adds a negative gravity component. These effects are essentially identical for the left and right U-frames. For the y-axis, the reductions are largely due to the negative z-axis acceleration (I) which has a component in the plane of the U-frames due to the 6° outward roll of the OLs (Fig. 2) and the right-ear-down tilt of the head (see supplemental video 2). The right ear down tilt of the head causes the y axis of the right U-frame to be closer to the z-axis of the E-frame than is the y-axis of the left U-frame, resulting in a greater deviation of the right OL profile (compared to the left OL profile) from the E-frame profile in H.