Forced to spend the day hitting their small skulls against the sides of trees in search of buried chunks, woodpeckers should have developed one or two tricks to prevent brain damage. So you would think.
A new study on woodpecker biomechanics has called into question speculation that the small bird with a chisel head avoids turning its brain into porridge through fantastic shock-absorbing adaptations.
Rather, your brain might just be too small for you to care.
“When analyzing high-speed videos of three woodpecker species, we found that woodpeckers do not absorb the impact shock with the tree,” says Sam Van Wassenbergh, a biomechanics researcher at the University of Antwerp in Belgium.
Anyone who has ever seen, or even just heard of, the machine gun fire of the characteristic touch of a woodpecker would appreciate the physics involved.
Members of some species can experience forces of up to 1400 g. Compare that to the insignificant 90 to 100 g that can cause a human concussion, and it’s easy to imagine the kind of trauma that could arise inside that little skull.
Previous research has pointed to a variety of body modifications that could help reduce the impact on the brain tissue of the woodpecker, such as spongy bones and that absorb shock and neck muscles.
While these features appear to be designed to absorb shock, demonstrating that they successfully reduce forces as the woodpecker’s head accelerates and decelerates quickly is a challenge.
There is also the question of whether woodpeckers even bother with safety features in the first place. Their small brains and tight skulls leave little room for shock.
In this study, using more than a hundred six-speed high-speed videos depicting the species Dryocopus martius, Dryocopus pileatus and Dendrocopos major, Van Wassenbergh and his team carefully measured the slowdown in their eyes when their beaks they were with the wood.
Since the eyeball is a fairly suitable proxy for the soft interior, researchers could calculate the physics of a decelerating skull.
It turns out that the whole head moves like a sun, with little variation in the maximum deceleration between the eye and the beak.
“Their heads basically function as rigid, solid hammers during the picking,” Van Wassenbergh says.
Biomechanical models constructed from data collected from a frame-by-frame analysis of their videos only verified that there was not a large shock absorption between the tip of the beak and the contents of the skull.
All these specialized bone structures, in this case, do not deform and absorb energy every time as much as they resist fracture.
This makes the work of the birds more impactful and efficient. “If the beak absorbed much of its own impact, the unfortunate bird would have to hit even harder,” the researchers explain.
While, according to a study, birds can suffer the effects of a lifelong headache, simulations by Van Wassenbergh and his team on the intracranial pressure of the woodpecker’s skull suggest that thrust and constant push on such small brains are not the same. to anything serious, anyway.
Woodpeckers do not have to worry about all these safety features.
“The absence of shock absorption does not mean that your brain is in danger during seemingly violent impacts,” says Van Wassenbergh.
“Even the strongest blows of the more than 100 woodpeckers that were analyzed should be safe for the woodpeckers’ brains, as our calculations showed lower brain loads than those of humans suffering a concussion.”
The findings help explain why woodpeckers never evolved to be much larger than about half a meter (about 22 inches) long. Although a pneumatic hammer with muscle feathers could pierce larger meals, your heavier brain would not be able to withstand the pressure.
This means that even though they have small brains, woodpeckers are not that stupid after all.
This research was published in Current Biology.