That is a common misconception. Shock absorption would diminish pecking performance. You want your hammer to be hard instead of soft if you want to get anything done. Woodpeckers have very stiff heads because of this.
By my thinking, the damage to the brain could outweigh the better foraging. Then I thought that the brain mooshing into the front of the skull later in the peck would turn the head into a dead-blow hammer, which are still quite effective hammers.
Huh, the link to the research article works for me. Weird. I'll post the summary below.
The woodpecker is trying to break the surface of the tree, whereas a dead-blow hammer is "helpful in minimizing damage to the struck surface", as said in that wikipedia article. The total impulse just means how much energy the bird is expending, whereas the peak force is what breaks the structure of the wood. So it's beneficial to get as hard of an impact as possible with the highest possible peak force.
The skull of a woodpecker is hypothesized to serve as a shock absorber that minimizes the harmful deceleration of its brain upon impact into trees^1–11^ and has inspired the engineering of shock-absorbing materials^12–15^ and tools, such as helmets.^16^ However, this hypothesis remains paradoxical since any absorption or dissipation of the head’s kinetic energy by the skull would likely impair the bird’s hammering performance^4^ and is therefore unlikely to have evolved by natural selection. In vivo quantification of impact decelerations during pecking in three woodpecker species and biomechanical models now show that their cranial skeleton is used as a stiff hammer to enhance pecking performance, and not as a shock-absorbing system to protect the brain. Numerical simulations of the effect of braincase size and shape on intracranial pressure indicate that the woodpeckers’ brains are still safe below the threshold of concussions known for primate brains. These results contradict the currently prevailing conception of the adaptive evolution of cranial function in one of nature’s most spectacular behaviors.
Van Wassenbergh S, Ortlieb E, Mielke M ...
Woodpeckers minimize cranial absorption of shocks
Current Biology, 2022; 32, 3189-3194.e4
I was unsure of the effect of the dead-blow, since "minimizing damage" and "same driving force" sound contradictory to me. The latter makes it sound as if both would drive a nail to the same depth, and I was thinking the beak is effectively a nail. I'm glad the paper mentions concussions, and I'll give em that bird and primate brains are probably similar enough in that respect.
Odd that the tongue wraps around though. I'd figure it would just slide down the neck, since that seems closer to what we have.
18 replies
It acts as a shock absorber for its brain.
That is a common misconception. Shock absorption would diminish pecking performance. You want your hammer to be hard instead of soft if you want to get anything done. Woodpeckers have very stiff heads because of this.
I'd guess that it just needs the space so it can extend that far into the tree, without blocking the airways.
Your link says the page does not exist.
By my thinking, the damage to the brain could outweigh the better foraging. Then I thought that the brain mooshing into the front of the skull later in the peck would turn the head into a dead-blow hammer, which are still quite effective hammers.
"A dead-blow hammer delivers the momentum over a longer period, resulting in less peak force, but similar total driving effect for the same head weight."
Huh, the link to the research article works for me. Weird. I'll post the summary below. The woodpecker is trying to break the surface of the tree, whereas a dead-blow hammer is "helpful in minimizing damage to the struck surface", as said in that wikipedia article. The total impulse just means how much energy the bird is expending, whereas the peak force is what breaks the structure of the wood. So it's beneficial to get as hard of an impact as possible with the highest possible peak force.
Van Wassenbergh S, Ortlieb E, Mielke M ... Woodpeckers minimize cranial absorption of shocks Current Biology, 2022; 32, 3189-3194.e4
Sweet, thanks for the info!
I was unsure of the effect of the dead-blow, since "minimizing damage" and "same driving force" sound contradictory to me. The latter makes it sound as if both would drive a nail to the same depth, and I was thinking the beak is effectively a nail. I'm glad the paper mentions concussions, and I'll give em that bird and primate brains are probably similar enough in that respect.
Odd that the tongue wraps around though. I'd figure it would just slide down the neck, since that seems closer to what we have.
I watched a video about this but idk where.
Jesus is that what cushions their brain from all the violent headbanging?
Actually no, they don't absorb any shock, otherwise their hammer would lose a lot of their efficiency
Before you get any ideas. They also have little hooks covering the end of it, to pull bugs out of tight places.
Is there anything holding it on? It looks like there's a possibility of the tongue just flying right out.
Quality TIL in my shitpost feed? Preposterous! 😤
What that tongue doing?
He shoves it in holes and licks the good stuff
Wait, what, yours doesn’t?
Mine wraps around a pecker's head regularly.
Me too!
I needed this, fellow shitposter. Thank you ✊