Birds' brains are probably so tiny that they cannot be damaged.
Scientists from the University of Antwerp put forward a new hypothesis, which explains why woodpeckers don't get concussions from constantly tapping trees in search of food. In their opinion, this is not due to additional shock-absorbing functions. Birds' brains are probably just too tiny to be damaged, Science Alert reports.
Anyone who's ever heard a woodpecker tap can appreciate the physics involved. These birds “twitch” their heads an impressive 20 times per second, some of them can feel a force of up to 1400 g. For comparison, only 90-100 g is enough for a person to get a concussion.
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In past studies, scientists have pointed to possible body modifications that could help reduce the impact on the woodpecker's brain tissue. For example, spongy shock-absorbing bones and neck muscles. These elements can soften the impact, but they can also weaken the force with which the woodpecker knocks on the tree.
In the new study, scientists observed six woodpeckers representing the species Dryocopus martius, Dryocopus pileatus and Dendrocopos major. They measured the deceleration of the birds' eyes at the moment when their beaks touched the tree.
The woodpecker's entire head appeared to move as a unit, with little difference in peak deceleration between the eye and beak. “Their heads basically function like hard, hard hammers when biting,” said lead study author Sam Van Wassenberg.
The models the scientists built based on video observations of woodpeckers further confirmed that between the tip beak and skull contents were not significantly damped. In this case, the specialized bone structures are not so much deformed and absorb the energy from each blow, as they resist destruction.
Some studies have shown that woodpeckers can suffer from constant blows to the head. But simulations conducted by Van Wassenberg's team show that such “shaking” of the head does not lead to anything serious.
Scientists' data can explain why the size of woodpeckers never exceeds half a meter. A larger “feather jackhammer” could help to obtain larger portions of food, but a heavier brain would not be able to withstand such pressure.
