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.
Scientists have long sought to understand how woodpeckers repeatedly pound their beaks against tree trunks without damaging their own brains.
Earlier studies theorised 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 absorbance 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,” Sam Van Wassenbergh, lead author of the study, said.
In the study, researchers quantified the impact decelerations during pecking in three woodpecker species.
They built biomechanical models which revealed that any shock absorbance of the skull would be disadvantageous for the birds.
Contrary to previous findings, researchers say while the deceleration shock with each peck exceeds the known threshold for a 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 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 over 100 pecks that were analysed should still be safe for the woodpeckers’ brains as our calculations showed brain loadings that are lower than that of humans suffering a concussion,” he added.
From an evolutionary perspective, scientists speculate that the findings may explain why there aren’t woodpeckers with much larger heads and neck muscles.
While a larger woodpecker could potentially deliver more powerful pecks, they say concussions likely would 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 absorber built into their head. This myth of shock absorption in woodpeckers is now busted by our findings,” Dr Van Wassenbergh said.