Belgian researchers debunk a popular theory that explained why woodpeckers do not suffer brain damage when cutting down trees, and offer an alternative. Their head is not a helmet, but a hammer.
The skull of a woodpecker is not a helmet. He looks more like a hammer. This is the conclusion of Belgian researchers who have published their results in the scientific journal Current Biology published. Thereby they disprove a widespread theory.
The erroneous statement had already gained considerable traction. On zoo signs and in the media, it is often stated that the woodpecker does not get headaches thanks to a helmet built into its skull. Even real protective materials have been designed based on this theory, but it can prove to be a recipe for failure.
The murmur in the room
A helmet is inconvenient
The researchers videotaped woodpeckers in action. They then made computer models based on that. They used this to analyze how the skull processes a hard blow. The skull doesn’t seem to absorb the shocks at all, but it hits back like a hammer.
The computer model also shows that a shock absorber would be inconvenient for the birds. To break through trees, a woodpecker with a built-in helmet would have to knock many times harder – which makes the pressure on the skull just as great.
With a sense of humor, the group makes clear how ridiculous the myth actually was. They pieced together a hammer with a coil spring, which mimics how we thought the woodpecker skull works. The spring renders the item completely useless. The underlying argument: A woodpecker with a built-in helmet is as nonsensical as a hammer with shock absorption.
The question still remains: how does a woodpecker prevent brain damage? The computer model is also useful for this. It confirms what scientists have suggested before: It is not necessary to prevent harm. The blow to the tree is simply not big enough to cause brain damage. The feeling may tell you that it is not a good idea to bang your head against a tree every day; in practice there is little wrong with that.
The old theory had been proposed by scientists in the middle of the twentieth century. They found a small soft spongy piece of tissue between the woodpecker’s eyes and beak. That would pretty much dampen the blow, was the idea. The Belgian researchers suspect that the tissue still plays a role. Not by dampening the shock, but by distributing it evenly over the skull. The skull is built in such a way that it can easily handle that force.
The study may also explain why larger woodpeckers with stronger neck muscles have never evolved in evolution, the researchers write. If woodpeckers were to chop harder, at some point it would be harmful to the brain.
‘It is a very interesting study that gives evolutionary biologists great insight into the development of bird skulls and birds as a whole,’ says Sander Gussekloo. He is a biologist at Wageningen University. ‘Finally, the actual accelerations and decelerations that occur when woodpeckers are chopped and their influence on the brain are finally being looked at.
“Since woodpeckers rely on hocks for food intake, sexual behavior and nest building, it is likely that the structure of the skull has evolved to optimize this,” he continues. ‘The anatomy of the skull is able to absorb forces very well, which can serve as inspiration for human structures.’
This is confirmed by Sam van Wassenbergh, professor of biomechanics at the University of Antwerp and author of the study. “Several scientific publications have been published that use woodpecker heads as a source of inspiration for designing protective equipment to absorb shocks. That’s why I thought it was important to test the hypothesis.’