Energy conversion in woodpecker on successive peckings and its role on anti-shock protection of brain

To investigate the mechanism of brain protection of woodpecker, we built a finite element model of a whole woodpecker using computed topography scanning technique and geometry modeling. Dynamic analyses reveal: (i) 99.7% of the impact energy is converted into strain energy in the bulk of body and 0.3% is converted into strain energy in the head after three successive peckings, indicating the majority of the impact energy is stored in the bulk of body; (ii) the strain energy in brain is mainly converted into the dissipated energy, alleviating the mechanical injury to brain; (iii) the deformation and the effective energy dissipation of the beaks facilitate the decrease of the stress and impact energy transferred to the brain; (iv) the skull and dura mater not only provide the physical protection for the brain, but also diminish the strain energy in the brain by energy dissipation; (v) the binding of skull with the hyoid bone enhances the anti-shock ability of head. The whole body of the woodpecker gets involved in the energy conversion and forms an efficient anti-shock protection system for brain.