The body of woodpeckers manages chiseling impacts thanks to its curved body shape and tail that acts as a bracing spring.


"[Franco] Lodato took as his model [for an ice axe] the woodpecker--a bird that chisels into wood to get at the insect larvae on which it feeds. Despite the bird's small size, it can manage 25 hits a second, with a surprisingly forceful impact. Studying the woodpecker's biomechanics further, Lodato found that its body is designed specifically for this movement. Woodpeckers brace themselves with their tails, which function as springs, taking advantage of both their center of gravity and their skull-bone configuration to absorb considerable stress. In other words, the birds did not hammer on the wood by using their necks. The finished axe consists of 'an inner core of titanium into which is inserted an adjustable aluminum point. These two parts are attached by a hinge inspired by the two valves of a mollusk. Special attention was dedicated to the shape of the handle. Rather than designing it to be straight, I incorporated into it a slight curve, again taking the body of the woodpecker as a model. This improves the efficiency of the blow.'" (Lodato 2005)

Web page
The nature of design