If a human tried chopping wood with his head, he'd lose at least one eye and sustain permanent brain damage. But woodpeckers do it all the live long day and sustain zero headular damage. How do they do it?
Theories have included: super powerful muscles, a special injury-preventing drilling technique, or a protective placement of the brain inside the skull. But no one has systematically analyzed the mechanics of a woodpecker's skull in as much detail as Fan Yubo and his team at the Key Laboratory for Biomechanics and Mechanobiology at Beihang University in China, who published their work today in Science China Press.
They spent three years studying the mechanical properties, microstructure and composition of the cranial bone and beak of the woodpecker, and compared it to that of the lark. They found that woodpeckers have developed their own amazing nanofabrication and self assembly capabilities in their cranial bone structure over millions of years of evolution.
The strength of the two types of birds' beaks is actually similar. But the woodpecker's cranial bone is much stronger than the lark's, the researchers found. That's thanks to having more "plate-like spongy bone" in its cranium, which makes it resistant to deformation. Specifically, it has a larger volume of structures called trabeculae, which are tiny spaces in the bone that form a mesh filled with bone marrow. The woodpecker's trabeculae are also spaced very close together, which helps diffuse impact. In the image, the woodpecker cranium bone is A; the lark's is B. C is the woodpecker's beak, D is the lark's.
The researchers hope their work might inspire new protective headgear for humans. I'm just happy to know this mystery of nature is solved. [Science China Press]