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Cynthia McKelvey
Oberlin Ohio

Interesting things from an overly-curious science nerd.

My posts are presented as opinion and commentary and do not represent the views of LabSpaces Productions, LLC, my employer, or my educational institution.

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Comment by Cynthia McKelvey in MDMA and "Drugs Live: The Ecstasy Trials"

Thanks! It's good to be back (again haha). It's definitely hard finding the time to write if you're fully employed elsewhere! I'd love to hear from Donna, but I'm not longer at UF so maybe you coul. . .Read More
Apr 30, 2013, 1:10pm
Comment by Brian Krueger, PhD in MDMA and "Drugs Live: The Ecstasy Trials"

Great to see you again!  I know I've had a hard time finding the time to continue writing with everything going on.  You know, one of the scicomm people that ran the internet outreach at UF gradu. . .Read More
Apr 29, 2013, 3:34pm
Comment by Cynthia McKelvey in Salty Penguins Filter Salt Out Their Nose

Hi Dan, Sorry it took me so long to reply to your comment. I actually didn't even see it for quite some time. I did do some research though, and it turns out that the fluid within the cavit. . .Read More
Apr 09, 2012, 12:46pm

This is fascinating! But where does the non-salty fluid come from (or START from)? It can't be the blood stream... . . .Read More
Mar 16, 2012, 2:55pm

Thanks! Haha yeah I was wondering if that first sentence could have been worded more clearly. Although I think I look better on my camera phone than I do IRL, but maybe that's because of the poor r. . .Read More
Mar 03, 2012, 7:15pm
Sunday, December 18, 2011

Despite being one of the more annoying animals, woodpeckers are actually pretty cool when you consider how well they're designed for what they do.  Their feet have two toes in front and two in back to better grip vertical surfaces.  Their stiff tails act like a third leg to balance themselves against the tree (or building) that they're pecking.  But what's really cool is their skull.
 
If you were to sit down and try to design a helmet, you might not think of looking towards nature for inspiration.  But while pecking, a woodpecker's head accelerates and decelerates at very high speeds.  In order to protect itself from injury due to impact, it has evolved several structural mechanisms to absorb the shock of repeatedly ramming its face into a tree.
 
Some of these structures include a very sharp and stout beak, which minimizes the impact of the beak hitting the tree, much like jumping into water feet-first minimizes the impact of the surface tension on the rest of the body.  The stoutness then helps to absorb most of the shock and prevent it from reaching the cranium of the skull.  There is also less space between the brain and the skull than in other animals, which helps to keep the brain from getting jostled around during impact.  Woodpeckers also have a long hyoid bone, which is attached to the tongue, forks and extends around the neck, up behind the skull, over the top, and into the right nostril, acting as a sling to cradle the skull.
Yes, really.  On the left is the skull of a woodpecker, where the hyoid can be seen extending up from behind the skull.  On the right labeled (b) is the woodpecker hyoid bone by itself.
In a recent article in PLoS ONE, researcher Yubo Fan and co. decided to look more closely at the engineering of the woodpecker skull.  By comparing the structure of a woodpecker to the soil-pecking Eurasian hoopoe using a high-speed videos, force and torque sensors, and micro-CT scanning, they were able to determine how the internal structure of the skull and beak interplay to absorb shock and prevent brain injury in woodpeckers.
 
First is the composition of the skull itself.  Bones are not entirely solid throughout, they are mostly composed of porous "spongey" bone, with a solid outside.  In the skull of a woodpecker, the spongey bone is made of a dense, plate-like organization, which acts like packing peanuts.  In contrast, the hoopoe has spongey bone that looks more like rods, which is less effective in absorbing shock.
 
The internal structure of the beak is also specially designed to absorb shock, with a longer outer tissue layer and a very tough internal bone.  In fact, the beak absorbs most of the shock during impact, as shown by this diagram demonstrating the distribution of force (shown in red) throughout the skull over the time of impact and recoil.
Finally, there's the distribution of force on the hyoid bone.  Its unique structure allows it to absorb any extra force from the impact on the beak and divert it away from the skull itself.  It also helps to keep the skull in place, like a seatbelt keeps a person in place during a car crash.
 
The woodpecker is turning out to be another inspiration from nature to engineers.  When trying to create a better helmet, why not look to the solutions that millions of years of evolution has produced?
 
Cross-posted to blogspot.
 
Images courtesy of PLoS ONE.
Reference: Wang, L.; Tak-Man Cheung, J.; Pu, F.; Li, D.; Zhang, M.; Fan, Y.  (2011).  Why Do Woodpeckers Resist Head Impact Injury: A Biomechanical Investigation.  PLoS ONE. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0026490

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Elena Caravela

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Like the new look!  Any thoughts on how to disuade a woodpecker from choosing the tree right behind your bedroom window? Seriously, great post.

 


Cynthia McKelvey
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Thanks!  Hm, not sure on how to dissuade peckers from pecking.  An airhorn would probably work, but then you might get the police knocking on your door for noise complaints.

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