Have you ever wondered how a woodpecker can repeatedly bash its beak against a tree and never become concussed or even just a little bit disorientated?
New research shows that woodpeckers like this pileated woodpecker I photographed in Banff National Park earlier this summer experience forces of 1500 g’s while pecking bark off trees to get to the tasty insects. To put that in perspective, the highest g force roller coasters are rated at only 5 g’s. Fighter jet pilots experience a maximum of 12 g’s and the highest short-term g force a person has every survived was just over 200 g’s. Nowhere near what a woodpecker experiences repeatedly throughout the day and never seems to suffer any harmful effects.
So what makes this possible? A few of the adaptations woodpeckers have include an elongated upper beak and beak internal structure that diverts the impact energy away from the brain or absorbs any excess in the spongy bone sitting in front of the skull. The energy diverted by the beak travels to the hyoid bone that wraps around the entire skull of woodpeckers and serves as a seat belt for the brain. Lastly, to prevent the brain from sloshing around, woodpecker brains are tightly packed against the skull with reduced cerebrospinal fluid (CSF) to prevent any movement.
To figure out how these adaptations help the woodpecker keep pecking at upwards of 20 pecks/second, researchers used CT scans to determine that they are able to deflect almost all (99.7%) of the impact to their heads through the rest of the body. What little remains is dissipated as heat in the beak and skull so that it never reaches the brain. This also explains why woodpeckers take frequent breaks from pecking on trees to let their heads cool down before their brains overheat! Pretty remarkable stuff with potential applications for helmet design to prevent concussions in people!
Certainly a group of birds with impressive adaptations. One day these birds might help save a lot of people from suffering brain damage and while we shouldn’t just care about nature for its benefits to us, it does provide one more reason to appreciate, preserve and learn more about the natural world.
Owen Slater Photography 