(ORDO NEWS) — Belgian researchers have refuted the popular hypothesis that the structure of the woodpecker’s skull absorbs impacts against a tree trunk.
On the contrary, the woodpecker’s head has evolved to increase the efficiency of pecking, and not to protect the brain. At the same time, the size and shape of the skull provide the intracranial pressure at which the woodpecker’s brain is safe.
Scientists have long wondered how woodpeckers don’t get concussions when they bang their heads on a tree trunk. The researchers believed that the design of their skull must somehow absorb shock.
This hypothesis remained paradoxical, as any absorption or dissipation of the kinetic energy of the head by the skull would likely impair the bird’s ability to chisel wood, and thus would not likely have evolved.
Now scientists from the University of Antwerp (Belgium) have refuted this assumption and have shown that the heads of woodpeckers look more like hard hammers than protective helmets.
The authors analyzed high-speed video footage of three species of woodpeckers ( Dendrocopos major , Dryocopus pileatus and Dryocopus martius ) chiseling tree bark.
For the first time, scientists have quantified the impact deceleration during pecking and have developed biomechanical models of the skulls of these birds.
The results showed that the head of woodpeckers is optimized to increase the efficiency of pecking, and not at all to protect the brain, since any depreciation of the skull would be extremely disadvantageous and energy-consuming for them.
After that, the question arose why such dynamic blows do not harm the brain of woodpeckers. If a man or a monkey were in place of the bird, the concussion would be provided.
Then the scientists conducted numerical simulations of the influence of the size and shape of the cranium on intracranial pressure.
It turned out that the pressure ensures the safety of the woodpecker’s brain even with strong impacts, since the force on it is lower than that which can lead to concussion in primates.
However, these birds can still get a head injury – for example, if they mistakenly start hammering metal with all their might.
The data obtained refute the popular hypothesis about shock absorption by the skull. If it were true, in the process of evolution, woodpeckers with much larger heads and strong neck muscles would certainly have appeared. But in this case, their brain and skull would reach such a size that the blows would become unsafe.
The results of the work also have some practical implications, as engineers have previously used woodpecker cranial anatomy as a source of inspiration when designing shock-absorbing materials and helmets. Given that woodpecker anatomy minimizes shock absorption, this may not be the best idea.
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