How do woodpeckers avoid brain injury?

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Slamming a beak against the trunk of a tree would seem like an activity that would cause headaches, jaw aches and serious neck and brain injuries. Yet woodpeckers can do this 20 times per second and suffer no ill effects.

Woodpeckers are found in forested areas worldwide, except in Australia. These birds have the unusual ability to use their beaks to hammer into the trunks of trees to make holes to extract insects and sap. Even more impressive they do this without hurting themselves.

We are materials scientists who study biological substances like bones, skins, feathers and shells found in nature. We are interested in the skull and tongue bone structure of woodpeckers, because we think their unusual anatomy could yield insights that could help researchers develop better protective head gear for humans.

Concussions in people

Woodpeckers endure many high impact shocks to their heads as they peck. They have strong tail feathers and claws that help them keep their balance as their head moves toward the tree trunk at 7 meters – 23 feet – per second. Then, when their beak strikes, their heads slow down at about 1,200 times the force of gravity (g). All of this occurs without the woodpecker sustaining concussions or brain damage.

A concussion is a form of traumatic brain injury caused by repeated blows to the head. It is a common occurrence and happens frequently during contact sports like football or hockey. Repeated traumatic brain injury eventually causes a progressive brain disorder, chronic traumatic encephalopathy (CTE), which is irreversible and results in symptoms such as memory loss, depression, impulsivity, aggressiveness and suicidal behavior.

The National Football League says concussions in football players occur at 80 g. So how do woodpeckers survive repeated 1,200 g impacts without harming their brain?

We have looked for the key secrets of the woodpecker’s ability to tolerate the high impact during the hammering. We studied the micro-structures of bones and then did a biomechanical analysis on the head.