Knock on, Woodpecker

I swear that I write posts about things other than birds, but I seem to be on an avian kick right now. So prepare for one more bird post, and then I promise to mix things up. During a recent trip to a nature exhibit, I learned that woodpeckers have a type of “shock absorber” in their heads to help them handle the continual hammering. I had not ever really thought about the science behind their pecking, so I decided to look further into it for this blog post.

Bird Brains: Why Don’t Woodpeckers Get Concussions

woodpeckerApparently, for woodpeckers, their hammering is tantamount to “going from 26,000 miles per hour to a complete stop every second.” Concussion-prone human brains could never handle this stress, but woodpeckers have a few adaptations to help them continue merrily head banging away. First, woodpecker brains have less of a “slosh factor” than human brains. A human brain is surrounded by a relatively large amount of cerebrospinal fluid to help cushion it and keep it healthy. However, this means that when a human head receives a hard blow, the brain can slosh around and hit the inside of the skull, which may cause a concussion. Woodpecker brains, conversely, fill the skull better, thereby decreasing the “slosh factor.” Another mode of protection for the woodpecker is simply its size. Their small body/brain size provides woodpeckers with a better surface area ratio. This allows the force from a cranial collision to be spread over a larger region of the skull. I found this VIDEO about woodpecker head design that I think explains the surface area aspect well (along with what concussions are and some of the other points I am going to cover). I thought the most interesting adaptation was the woodpecker’s hyoid bone. It wraps all the way around the woodpecker’s skull and has muscles attached to it that allow the woodpecker to extend its tongue. The design of the hyoid means that it can act sort of like a “seatbelt” for the animal’s brain when the muscles around the hyoid contract. It also aids in diverting vibrations away from the brain. Finally, the hyoid/tongue pinch the woodpecker’s jugular vein, thereby increasing blood volume in the skull (i.e. decreases “slosh factor”). I found the whole hyoid/tongue thing a bit difficult to wrap my head around (ha!) but found this article helpful: Bone protects brain from injury: Woodpecker.

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Depiction of woodpecker hyoid bone and tongue

Scientists have begun to capitalize on the woodpecker’s amazingly bizarre head design to improve brain health for athletes in contact sports (e.g. American football; This Woodpecker-inspired Collar Could Protect Athletes from Concussions). Engineers have developed a collar that essentially does the same thing as the woodpecker’s hyoid/tongue design by pinching the athlete’s jugular vein so that the blood volume increases in the brain and forces the brain to take up more space. Consequently, the collar cuts down on the brain’s “slosh factor.” I am not sure how popular these types of collars are with athletes yet, but hopefully researchers make some progress cutting back on concussion rates. I knew concussion rates were high, but the images of athlete brains with chronic traumatic encephalopathy (CTE) are shocking. We were definitely not built to be woodpeckers!

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Boston University Center for the Study of Traumatic Encephalopathy [CC BY-SA 4.0; http://creativecommons.org/licenses/by-sa/4.0%5D

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