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sábado, outubro 29, 2011

Why Do Woodpeckers Resist Head Impact Injury: A Biomechanical Investigation

Lizhen Wang1,2, Jason Tak-Man Cheung3, Fang Pu1, Deyu Li1, Ming Zhang2*, Yubo Fan1*

1 Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, People's Republic of China, 2 Department of Health Technology and Informatics, the Hong Kong Polytechnic University, Hong Kong, 3 Li Ning Sports Science Research Center, Beijing, People's Republic of China


Head injury is a leading cause of morbidity and death in both industrialized and developing countries. It is estimated that brain injuries account for 15% of the burden of fatalities and disabilities, and represent the leading cause of death in young adults. Brain injury may be caused by an impact or a sudden change in the linear and/or angular velocity of the head. However, the woodpecker does not experience any head injury at the high speed of 6–7 m/s with a deceleration of 1000 g when it drums a tree trunk. It is still not known how woodpeckers protect their brain from impact injury. In order to investigate this, two synchronous high-speed video systems were used to observe the pecking process, and the force sensor was used to measure the peck force. The mechanical properties and macro/micro morphological structure in woodpecker's head were investigated using a mechanical testing system and micro-CT scanning. Finite element (FE) models of the woodpecker's head were established to study the dynamic intracranial responses. The result showed that macro/micro morphology of cranial bone and beak can be recognized as a major contributor to non-impact-injuries. This biomechanical analysis makes it possible to visualize events during woodpecker pecking and may inspire new approaches to prevention and treatment of human head injury.

Citation: Wang L, Cheung JT-M, Pu F, Li D, Zhang M, et al. (2011) Why Do Woodpeckers Resist Head Impact Injury: A Biomechanical Investigation. PLoS ONE 6(10): e26490. doi:10.1371/journal.pone.0026490

Editor: Mark Briffa, University of Plymouth, United Kingdom

Received: April 11, 2011; Accepted: September 28, 2011; Published: October 26, 2011

Copyright: © 2011 Wang et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding: This project was funded by National Natural Science Foundation of China under the Grant 10925208, 11120101001 (http://www.nsfc.gov.cn/Portal0/default12​4.htm) and by the Hong Kong Polytechnic University under the grant G-U624 (http://www.polyu.edu.hk/cpa/polyu/index.​php). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

* E-mail: ming.zhang@polyu.edu.hk (MZ);