Woodpecker beaks absorb tremendous shocks when battering trees to get to grubs within. Like most birds, a woodpecker’s outer beak layer is a keratin sheath, arranged in a scale pattern, with defined edges between each scale. The scale edges of woodpecker beaks follow a zigzag pattern. Other pecking birds have a straight scale edges. The zigzag deflects compressing forces as a beak hits wood. Woodpecker beak scales are thinner and more elongated, affording greater scale sliding, which serves for shock absorption.
The middle “foam” layer of a woodpecker beak is more porous than in other pecking birds. This directs the energy of impacts to other parts of the woodpecker’s head that are better equipped to absorb shock. All told, woodpecker beaks have an unimaginably sophisticated design for battering wood while not damaging a fragile skull.