Because nails do not suffer from concussion

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Woodpeckers beat the wood of trees with their beak for three reasons: to find insects, larvae, and eggs that feed on them; to build a nest. And communication with other peaks, indicating the extension of its territory or presence to any partners. This is why they may also tap on metal surfaces where they do not hope to make holes.

Whatever the reason, it is clear that they have a structure that allows them to avoid constant concussions with this behavior. For anyone, repeatedly hitting their face on a hard surface would definitely not be a healthy behavior. Until now, the most accepted theory about this aspect of woodpeckers’ life has been that their skulls were shaped to absorb blows taken during knocking. However, this hypothesis has been challenged by a new study by researchers from the University of Antwerp and Published in the scientific journal current biology.

The study authors detailed videos of six woodpeckers of three different species hammering into a piece of wood in their lab, viewed in slow motion. In particular, they noted the relative positions of a point on the bird’s beak and another in its eye, which were taken as a reference for the position of the brain: it turns out that the deceleration experienced by the woodpecker’s brain after a blow against it. The wood is the same as the beak, if not faster. This indicates that there is no absorption, otherwise the eye decelerates more slowly, like a passenger in a car after an accident and the airbag deploys.

To illustrate what this means, biologist Sam Van Wasenberg, first author of the study, modified the hammer by inserting a spring between the head (the hammer part) and the stylus (the pointed part), as shown in 1:23 of the video.: This tool absorbs the force of the blow. , but it doesn’t beat well.

Shaping the potential skull in such a way that it softens the blows would have the same problem, for the tops: it would reduce the perceived impact, but would not allow the force to be transmitted to break the wood. In short, you should hit the peaks with more force.

According to Van Wassenbergh and colleagues, the reason why nails don’t constantly concussive would be simpler: the energy their brains absorb when hitting wood is much less than what a concussion would cause in a person. They had to crash into a tree twice as fast to get it. “Spikes are much smaller than humans and smaller animals can tolerate more deceleration, just think of a fly hitting a window glass and then flying off as if nothing had happened,” Van Wasenberg explained.