The woodpecker's head acts more like a stiff hammer than a safety helmet
Frame sequence from a high-speed video of a woodpecker pecking (Dryocopus pileatus). Credit: Erica Ortlieb & Robert Shadwick (University of British Columbia)
Scientists have long wondered how woodpeckers can repeatedly pound their beaks into tree trunks without damaging their brains. This led to the idea that their skulls should act like shock-absorbing helmets. Now, researchers report in the journal Current Biology on July 14 have disputed this idea, saying that their heads act more like stiff hammers. In fact, their calculations showed that any shock absorbers would hinder the woodpecker’s pecking ability.
“By analyzing high-speed videos of three species of woodpeckers, we found that woodpeckers do not absorb shocks from impacting trees,” said Sam Van Wassenbergh of the Universiteit Antwerp, Belgium.
Van Wassenbergh and his colleagues first calculated the effects of slowing down during pecking at three woodpecker species. They used the data to build a biomechanical model, which led them to the conclusion that any shock absorption in the skull would be detrimental to the bird.
But if their skulls don’t act as shock absorbers, does angry pecking harm their brains? Apparently not. While the deceleration shock with each peck exceeds the known threshold for concussion in monkeys and humans, the smaller woodpecker brain can withstand it. Van Wassenbergh says that woodpeckers can make mistakes, for example if they peck at metal with full force. But their habit of pecking at tree trunks is generally well below the threshold for causing a concussion, even without their skull acting as a protective helmet.
“The absence of shock absorption does not mean their brain is in danger during a seemingly violent impact,” Van Wassenbergh said. “Even the strongest shock of the more than 100 blows analyzed should still be safe for the woodpecker brain because our calculations show a lower brain load than humans suffering from concussions.”
The findings refute long-standing theories about shock absorption, which have been popularized in the media, books, zoos and more, said Van Wassenbergh. “While filming woodpeckers in zoos, I have watched parents explain to their children that woodpeckers don’t get headaches because they have shock absorbers attached to their heads,” he said. “This shock absorption myth in woodpeckers is now debunked by our findings.”
From an evolutionary point of view, he said the findings might explain why there were no woodpeckers with much larger head and neck muscles. While larger woodpeckers can deliver a stronger kiss, a concussion is likely to cause them big problems.
The findings also have some practical implications, he added, given that engineers had previously used the anatomy of the woodpecker skull skeleton as a source of inspiration for the development of shock-absorbing materials and helmets. The new findings suggest it’s not a good idea, given that the anatomy of the trigger minimizes shock absorption.
Van Wassenbergh noted that another recent study by his team showed that woodpecker beaks often snagged, but the birds freed themselves quickly with alternating movements of the top and bottom of their beaks. They are now studying how the shape of the beak is adapted for pecking.
How do woodpeckers avoid brain injury?
Sam Van Wassenbergh, Woodpecker minimizes cranial absorption of shock, Current Biology (2022). DOI: 10.1016/j.cub.2022.05.052. www.cell.com/current-biology/f … 0960-9822(22)00855-7
Quote: The woodpecker’s head acts more like a stiff hammer than a safety helmet (2022, 14 July) retrieved 15 July 2022 from https://phys.org/news/2022-07-woodpeckers-stiff-safety-helmets.html
This document is subject to copyright. Apart from any fair dealing for purposes of personal study or research, no part may be reproduced without written permission. Content is provided for informational purposes only.
#woodpeckers #acts #stiff #hammer #safety #helmet
Comments
Post a Comment