A Woodpecker's Safety Lesson
by Paul Hess
In my July 2011 News and Notes column in Birding, I pointed to the encouraging prospect that “a woodpecker’s skull might save your life someday.” The topic was an engineering team’s analysis of how a woodpecker’s brain is protected from tremendous shock when the bill rams into hard wood.
The protection comes from a unique “shock absorber” built into the woodpecker’s skull, which the researchers were able to mimic mechanically. They created an analogous design that improves the effectiveness of devices called accelerometers, which sense and react to powerful impacts—for example, automotive airbags.
Sam Sinderson, who happens to be a birding companion of mine for 40 years, responded with a letter to the editor in the September issue of Birding. A retired engineer and an ardent sports fan, Sinderson suggested that sports leagues, sports-medicine leaders, and the sports helmet industry should find out whether the woodpecker’s shock-absorbing system might help to protect players from head injuries.
It turns out that another research team had been thinking about head injuries, too. In an October 2011 paper, Lizhen Wang and five colleagues in China describe a high-tech analysis of the skull and bill of a Great Spotted Woodpecker (Dencrocopos major). The authors emphasize safety from head trauma as a potential application of what they learned. (photo at left by Richard Towell)
Wang’s team found that the woodpecker’s protective biomechanics involve three elements:
• A spongy bone at the rear of the skull that serves as the shock absorber. This is the structure the engineering team had previously mimicked with success.
• The hyoid apparatus, a woodpecker’s specialized structure that supports the long tongue and wraps entirely around the skull from the lower to the upper mandible. The authors compare this to a safety belt.
• Slightly unequal lengths of the upper and lower mandibles. The lower mandible, although only 1.2 millimeters longer than the upper, strikes the tree first and diverts part of the pecking impact away from a direct hit on the brain.
Those three elements operate in what the authors call a “cooperative phenomenon . . . that may inspire new approaches to prevention and treatment of human head injury.”
Reports of concussions, especially in football and ice hockey, are appearing in the sports news with frightening frequency. We should all join Sinderson in hoping that helmet manufacturers and league officials take notice of the woodpecker’s lesson.