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New research sheds light on woodpeckers’ amazing pecking abilities

Scientists previously thought woodpeckers' heads acted as shock absorbers to avoid brain damage from their furious pecking. New research appears to debunk this theory.

(CN) — How do woodpeckers not get concussions? This oft-Googled question has stumped scientists for years. The leading hypothesis is their skulls act as shock absorbers, protecting the birds' brains against repeated violent impacts. But a new paper, published Thursday, appears to debunk that notion — arguing instead that woodpeckers’ heads act more like stiff hammers than helmets.

Researchers at the University of Antwerp analyzed slow-motion video of three different species of woodpeckers and figured out a way to quantify the decelerations their heads made from each impact while pecking. Using that data, they built biomechanical computer models of the birds and concluded that any shock absorbance of the skull would hinder the woodpeckers’ pecking abilities.

“While filming the woodpeckers in zoos, I have witnessed parents explaining to their kids that woodpeckers don’t get headaches because they have shock absorber built into their head,” said lead author Sam Van Wassenbergh in a statement accompanying the study. “This myth of shock absorption in woodpeckers is now busted by our findings.”

Slow-motion clips of high-speed videos of head impact during pecking (Current Biology/Van Wassenbergh et al)

Which leads back to the question: Why don’t woodpeckers get brain damage? It turns out that the woodpeckers are saved from injury by their relatively small brains. While the force their heads take from the violent pecking would be enough give humans or monkeys concussions, woodpeckers’ small brains and unique cranium design can just about withstand the impacts from pecking wood. If the woodpeckers tried to peck metal, on the other hand, they would sustain brain trauma.

“Even the strongest shocks from the over 100 pecks that were analyzed should still be safe for the woodpeckers’ brains as our calculations showed brain loadings that are lower than that of humans suffering a concussion," said Van Wassenbergh.

The theory may also help explain why there aren’t larger woodpeckers. Larger woodpeckers might have larger brains, which couldn’t withstand such shocks.

While the paper debunks a “long-standing misconception about the presence of shock absorption in woodpeckers,” as it reads, it opens up “a range of new questions about cranial function. How do woodpeckers manage to achieve this high stiffness in their cranial system, which includes a lower beak that can depress and retract, as well as an upper beak that has retained the capacity to rotate in the sagittal plane about the naso-frontal hinge?”

Van Wassenbergh and his colleagues hope to answer these questions in the future.

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