Why Don't Woodpeckers Get Headaches?
If you spent all day hitting your head against the wall you’d probably end up with brain damage, concussion or at the very least a nasty headache. So why is that woodpeckers can spend so much time hitting their heads against tree trunks yet seemingly not suffer any adverse side effects?
A team of Chinese scientists conducted an experiment on great spotted woodpeckers to find out how they are able to avoid getting brain damage from this behaviour by placing the birds in metal cages with high-speed cameras to observe them.
The researchers found that woodpeckers can hit their heads up to 20 times per second and around 12,000 times a day but strong muscles in their necks combined with thick inner eyelids prevents them from doing any damage to themselves.
Unlike the human brain, which will bounce about if it receives a blow, woodpeckers’ brains are tightly confined within their skull. Just before impact the woodpecker contracts its neck muscles which pushes the force down through its body and closes its inner eyelid. If it wasn’t for this extra eyelid the retina could tear or in the worst case scenario the eye could pop out of its socket.
The scientists also believe that the structure of woodpeckers’ beaks also helps prevent brain injuries by diverting the stress of the impact away from the top of their head and skull to the lower beak.
The woodpecker’s technique is also important; they never strike the tree from the side but hit the wood from head on.