Did you know that when a woodpecker pecks into tree or a telephone pole, the force is equivalent to a 1000 times that of gravity – which is the same as a human hitting their head against a wall at a speed of 25km an hour? That makes you think: how does the woodpecker avoid brain damage, with its continuous pecking an average of 12 000 times a day?
An anti-shock body structure
Woodpeckers have a unique anti-shock body structure which absorbs 99.7% of the impact. In humans, there is a horseshoe-shaped hyoid bone which acts as an attachment site for certain throat and tongue muscles. Woodpeckers’ hyoids do the same job, but they’re much larger and are differently shaped.
The hyoid bone in a woodpecker is a looping structure that wraps all the way around the skull and, in some species, even around the eye socket or into the nasal cavity, eventually meeting to form a sort of sling shape. I like to think of it as a safety-belt, absorbing shock and keeping the floating brain from shaking, rattling and rolling inside the skull with each peck.
A beak and skull built to prevent trauma
A woodpecker’s beak helps prevent trauma, too. The outer tissue layer of its upper beak is longer than the lower one, creating a kind of overbite, and the bone structure of the lower beak is longer and stronger than the upper one. It’s been suggested that the uneven build diverts an asymmetrical force that lowers the impact reaching the brain.
The skull of the woodpecker is an uneven, spongy, plate-like structure thickened around the forehead and the back of the skull, where it acts as a shock absorber. In this way, it helps distribute the incoming force in various directions, so the impact is deflected.
A combination of features
Let’s talk about that 0.3% of impact that isn’t absorbed when a woodpecker strikes his head, and that DOES go to the head and the brain. That 0.3% is mechanical energy gets converted into heat, which causes the temperature of a woodpecker’s brain to increase. These clever birds seem to have figured out a way to deal with this too! Woodpeckers usually peck in short bursts with breaks in between, and researchers think that these pauses give the brain time to cool down before the head banging starts again and brings the temperature back up. It is the combination of all these features, rather than any single one, that keeps woodpeckers’ brains protected so that they can peck without injury.
What can we learn from them?
It’s an incredible anatomical adaptation! Perhaps we could learn a thing or two about how to potentially design our head gear for contact sports. Currently there is no evidence for using a scrum cap or helmet to PREVENT A CONCUSSION, as these pieces of equipment can’t stop the floating brain from smashing into a hard skull on impact or in a whiplash. What helmets and scrum caps do help with though, is preventing a skull fracture or some facial injuries.
