Woodpecker skulls don’t behave like shock-absorbing helmets as previously thought, according to a new study that suggests their heads are more like stiff hammers.
Scientists have long tried to understand how woodpeckers repeatedly pound tree trunks with their beaks without damaging their own brains.
Previous studies theorized that the skulls must act like shock-absorbing helmets.
However, new research, published Thursday in the journal Current Biologyrefutes this idea, saying that their heads act more like stiff hammers.
Scientists, including those at the University of Antwerp in Belgium, calculate that any shock absorption from the skull would hinder the woodpeckers’ pecking ability.
“By analyzing high-speed videos of three species of woodpeckers, we found that woodpeckers do not absorb the shock of impact with the tree,” said Sam Van Wassenbergh, lead author of the study.
In the study, researchers quantified impact delays during pecking in three woodpecker species.
They built biomechanical models that showed that any shock absorption from the skull would be detrimental to the birds.
Contrary to previous findings, researchers say that while the deceleration shock with each peck exceeds the known threshold for concussion in monkeys and humans, the birds’ smaller brains can withstand it.
Woodpeckers’ usual pecking at logs is well below the threshold for causing a concussion, even without their skulls acting as protective helmets, according to scientists.
“The absence of shock absorption does not mean that their brains are at risk during the apparently violent effects,” said Dr. Van Wassenbergh.
“Even the strongest shocks of the more than 100 pecks analyzed should still be safe for the woodpeckers’ brains, as our calculations showed brain loads lower than those of people with concussions,” he added. .
From an evolutionary perspective, scientists speculate that the findings may explain why there are no woodpeckers with much larger head and neck muscles.
While a larger woodpecker could potentially deliver more powerful pecks, they say concussions would likely cause them big trouble.
“While filming woodpeckers in zoos, I have seen parents explain to their children that woodpeckers don’t get headaches because they have a shock absorber in their head. This myth of shock absorption in woodpeckers is now being broken by our findings,” said Dr. Van Wassenbergh.