Woodpecker skulls do not act like shock-absorbing helmets as previously thought, according to a new study that suggests their heads are more like stiff hammers.
Earlier studies theorised that the skulls must be acting like shock-absorbing helmets.
However, new research, published on Thursday in the journal Current Biology, refutes this notion, saying that their heads act more like stiff hammers.
Scientists, including those from the University of Antwerp in Belgium, calculate that any shock absorption from the skull would actually hinder the woodpeckers’ pecking abilities.
“By analysing high-speed videos of three species of woodpeckers, we found that woodpeckers do not absorb the shock of the impact with the tree,” said Sam Van Wassenbergh, lead author of the study.
In the study, researchers quantified the impact decelerations during pecking in three woodpecker species.
They built biomechanical models that revealed any shock absorption of the skull would be disadvantageous for the birds.
Shock absorber or hammer? A study on the cranial #biomechanics of #woodpeckers involving @UAFunmorph members Sam Van Wassenbergh and Maja Mielke was published today in @CurrentBiology https://t.co/IVU7PQ1lbM (1/n)
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Contrary to previous findings, researchers say that although the deceleration shock with each peck exceeds the known threshold for concussion in monkeys and humans, the birds’ smaller brains can withstand it.
The usual pecking of woodpeckers on tree trunks, according to scientists, is well below the threshold necessary to cause a concussion, even without their skulls acting as protective helmets.
“The absence of shock absorption does not mean their brains are in danger during the seemingly violent impacts,” Dr Van Wassenbergh said.
“Even the strongest shocks from the 100-plus pecks that were analysed should still be safe for the woodpeckers’ brains because our calculations showed brain loadings that are lower than those of humans suffering concussion,” he added.
From an evolutionary perspective, scientists speculate that the findings might explain why there aren’t woodpeckers with much larger heads and neck muscles.
Although a larger woodpecker could deliver more powerful pecks, say the scientists, concussions would probably cause them major problems.
“While filming the woodpeckers in zoos, I have witnessed parents explaining to their kids that woodpeckers don’t get headaches because they have shock-absorbers built into their heads. This myth of shock absorption in woodpeckers is now busted by our findings,” Dr Van Wassenbergh said.