Figure 5.

Instantaneous power requirement during prey capture in S. leptorhynchus as calculated by inverse dynamic modelling. The total power that needs to be generated by the epaxial and hypaxial muscle–tendon complexes to cause the observed feeding manoeuvre equals the sum of the powers needed to rotate the head and translate the anterior part of the body (a). The grey line at 1121 W kg⁻¹ indicates the highest peak instantaneous contractile power output measured for vertebrate muscle (Askew & Marsh 2001). Power requirement values exceeding this line demonstrate the use of an elastic power enhancement mechanism. Graph (b) shows that overcoming the head's inertia is the dominant factor in the dynamics of head rotation, followed by the effect of added mass and steady-state drag. The dynamics of the countermovement of the body are dominated by the body's inertia as well as the effect of added mass of the surrounding water (c). Drag is less important in the latter case. The negative powers calculated in the deceleration phase (after time=2 ms) of head rotation in (b) imply that energy can be restored in elastic structures of the feeding system (for example the protractor hyoidei tendons) or used to generate suction.