How does a woodpecker work? An impact dynamics approach

Abstract

To understand how a woodpecker can accelerate its head to high velocity in a short time without injury, a multi-rigid-segment model of its body was established based on skeletal specimens and high-speed video analysis. The study found that the high head velocity results from a whipping effect produced by coordinated muscle torques and tendon stiffness. By comparing the responses of hinged and rigid rods, three response modes were identified; among them, Mode II achieves the highest free-end velocity, analogous to the woodpecker’s strike. The multihinge model further showed that the free-end velocity increases with the number of hinges, explaining how the woodpecker’s long neck enhances impact speed.

Yuzhe Liu(刘雨喆)

Professor of Biomechanics