Construction workers don gloves and earplugs when wielding jackhammers. Motorcyclists wear helmets when they ride. It stands to reason that woodpeckers would evolve some kind of comparable safety gear to protect their heads from the constant, repetitive stress of banging their face against a woody surface.
That assumption, it turns out, would be wrong. While natural history is littered with animals who have evolved bony or cartilaginous armor to protect from heavy blows — including animals like rams, or armored dinosaurs like the ankylosaurus — woodpeckers have surprisingly little protection from such vibrations.
