Why Don’t Woodpeckers Get Concussions?


Wood is tough stuff, which is why we use it
to hold up houses and trees use it to hold up themselves. If you’ve ever swung an axe against a
tree, you know chipping away wood takes a lot of force. Now imagine chipping away that wood with your
face. That’s what it’s like to be a woodpecker. Hammering a tree, 20 times a second, ten thousand
times a day… face-first. The force of a peck is like as headbutting
a tree at full sprint, which you should not try at home. So why don’t woodpeckers get concussions? And if they did, what would they see flying
around their head? [OPEN] They say it’s not the fall that kills you,
it’s the sudden stop at the end. Anyone who’s ever watched a crash test video
knows that when the car stops moving, the bodies inside it don’t. This is basically the inside of your head
right before you get a concussion. The human skull is surprisingly strong and
flexible, but the delicate hunk of meat inside is more like a blob of jello floating in liquid. A rapid deceleration can cause your brain
to hit the inside of your skull and damage neurons and other cells. This is called a concussion. I’ve a couple concussions have had before. I felt dizzy, and… I actually don’t remember much else. When your brain gets sloshed and squished,
twisting forces happen down on the smallest level, deforming and tearing nerve cells,
and damaged neurons can’t don’t goodly communicate good. If nerves are damaged in the right area, you
can lose consciousness, but you don’t have to be knocked out to get a concussion, and
even smaller impacts can have lasting damage. CTE is a brain disease caused by repeated
impacts that can lead to bad things. When doctors did autopsies on former professional
football players they saw brains that looked wasted away, from years of repeated impacts
that weren’t technically concussions. Millions of concussions will happen to young
athletes this year, and that’s not counting brain injuries from accidents and other causes. It’s a big problem, and some scientists
are wondering if we can learn anything from hard headed birds. Woodpeckers are built for headbanging. Spongy skull bones, even special eyelids that
close just before impact, but their real anti-headache secrets are deeper inside. Woodpeckers will hammer to show off territory
or make nests, but mostly it’s to look for food. After they drill a hole, they use their tongue
like a spear to reach inside and draw out insects or nectar. But considering that tongue can be three
times the length of its beak, where do they keep it when it’s not being used? There’s a bony support /inside/ bird tongues
called the hyoid. We have a hyoid bone too, /underneath/ our
tongue, but in a woodpecker, it goes out the back of its mouth, all the way around its
skull, and ends up between its eyes. Scientists think this bone and muscle wrapper
may act like a seatbelt and absorb some of the shock when the bird’s head de-celerates. But consider acorn woodpeckers: They can drill
thousands of holes in a single tree and hammer a seed into each one. A seatbelt tongue can’t be enough to keep
them headache-free. One of the basic equations of physics is “Force
equals mass times acceleration”, or deceleration. But what really matters for impact injury
is how much area that force is being applied to, or why you should lie on a bed of nails,
not do a headstand on one. From the side, the human brain is basically
a half circle, oriented like this. So impact on the forward/backward axis focuses
the force on a small area. A woodpecker’s brain is oriented differently,
so forward/backward force is distributed over a larger area of the brain, and since they’re
packed more tightly in their skulls, they don’t slosh around like ours do. G-force is our measure of relative acceleration. We normally feel 1 g, the standard acceleration
of gravity on Earth. The g-force a body can survive depends a lot
on how long that body is being g-forced. If you love roller coasters, you’ve probably
experienced several seconds at 5 g’s and walked away smiling. But race car drivers have survived crashes
with over 200 g’s, but only because that deceleration was limited to a few milliseconds. Basically if you’re gonna hit something
hard, it helps to do it quickly. It takes less than a millisecond for a woodpecker’s
head to move from full speed to stopped. In that amount of time, our brains could take
300 g’s before concussion, but woodpecker brains can withstand more than four thousand
G’s. How is that possible?! This gets us to the real reason woodpeckers
don’t get concussions. J.B.S Haldane, in a 1926 essay “On Being
the Right Size” wrote that “You can drop a mouse down a thousand-yard mine shaft; and,
on arriving at the bottom, it gets a slight shock and walks away.” But dropped down the same mine shaft “…A
rat is killed, a man is broken, a horse splashes.” I don’t think anyone’s actually tested
that, but it comes down to simple math. As an animal, or an animal’s brain gets
smaller, the volume and mass drop by the cube, but the surface area goes down by the square. So a woodpecker brain might have much much
less skull area to absorb impact than we do, but it’s much, much, MUCH lighter. An engineer would say woodpecker brains and
human brains are built from the same material, but the mathematics of scale mean that bird
brains can take a bigger banging. So the main reason woodpeckers don’t get
concussions is because they’re small. I know, it’s kind of obvious, but we’re
stuck with a hard knock truth: they evolved to take an impact, and we didn’t, and as
long as we keep banging our heads into each other for fun or by accident, we’ll probably
keep getting concussions, no matter what kind of space-age bubble wrap we put on our heads. That’s being a whole different kind of hard-headed,
I guess. Stay curious.

100 Replies to “Why Don’t Woodpeckers Get Concussions?”

  1. "deceleration" is not a proper term, especially when discussing science, after hearing that "word", I do not trust this video's information.

  2. I mean, the football players that don't get concussions will survive longer and have more children than the ones that do get concussions. of course that just a generalization, and there are football players that didn't get concussions that have died before those that do.

  3. So according to his theory any bird (or other creature) the same size or smaller than a woodpecker should be able to withstand that same force. Sounds pretty questionable😕

  4. I think the answer is a more biologically oriented subject. More along the lines of what makes the brain be able to withstand the impacts due to increased cytoskeletal features within the brain…

  5. Me literally 22 mins ago..

    YouTube: "wanna see a video of a woodpecker pecking wood for 22 mins?"

    After watching the whole video, I wondered why woodpeckers never get dizzy..

    Youtube: "wanna watch why woodpeckers don't get dizzy from pecking for 6 mins next?"

    And here I am…

  6. the fall actually can kill you. if it's from a very high altitude you would burn to a crisp when entering the thicker lower atmosphere when at terminal velocity in the thinner atmosphere. it'll be like hitting a lava wall… or if the fall causes you to have a heart attack and die before the impact.

  7. Who found out the limit for a woodpecker and saw how much force it could take before getting a concussion and/or dying? I guess Stallone is not part woodpecker.

  8. Graphics on the video these days is out of control! It takes a lot away from the substance of the video. It's a distraction at best. Graphics should be used to explain complex ideas and arguments. Otherwise it serves no purpose

  9. your "ultimate theory" doesn't hold up. On account of large mammals that should be suffering concussions as well and have brains the size of ours so your mass to Energy relation Formula does not hold true….🤷

  10. There’s a woodpecker just outside my window banging on tree it’s loud! Amazing that that don’t injure themselves

  11. i was going to say we have to make some sort of system for people wearing iron man/woman suits, in major situations, what types of implants or shock system would protect their brain?

  12. There’s this woodpecker that thinks it’s funny to wake me up every other Sunday at 6 am to peck at the blind spot of my window.

  13. Here's an interesting tidbit for anyone who cares. Speed is the rate of change in position, right. Then accelleration is the rate of change in your speed. But what a lot of people don't know of is jerk, which is the rate of change in accelleration. So when you're decelerated quickly from 10m/s^2 to 0, you experience a large amount of jerk.

    There is a measure of the rate of change of jerk, too. It's called snap. The rate of change in snap is called crackle, and the rate of change of crackle is pop. Or if you wanna get technical, these are derivatives. I just find the idea of the rate of change of acceleration intriguing since it's something I've never given thought to before I learned about it. It's also a suprisingly nonintuitive thing to think about. Which I love.

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