Research Refutes Common Theory on Woodpeckers

Why don't woodpeckers knock themselves loopy when bashing their head against a tree? For years, the prevailing wisdom has been that they have some kind of natural shock absorber in their skulls to protect their brains, explains NPR. But a new study in Current Biology refutes the idea. By analyzing video of woodpeckers in action, the researchers have concluded that no such protection exists. The old idea doesn't actually make much sense upon close inspection anyway, writes Ed Yong at the Atlantic. "If what you need is a hammer, why strap a cushion onto its head?"

The researchers pored over video to look for telltale signs of such a cushion. "If something in a woodpecker’s skull were absorbing these shocks before they reached the brain—the way a car’s airbag absorbs shocks in an accident before they reach a passenger—then, on impact, a woodpecker’s head would decelerate more slowly compared with its beak," per the New York Times. The researchers discovered that no such difference in deceleration was taking place. If that's the case, then how do they avoid brain damage? Lead researcher Sam Van Wassenbergh of the University of Antwerp in Belgium suggests the answer is deceptively simple.

"We forget that woodpeckers are considerably smaller than humans," he tells the Times. "Smaller animals can withstand higher decelerations. Think about a fly that hits a window and then just flies back again." Essentially, the woodpeckers' brains are so small and light that they can withstand the blows. Using computer models, the researchers determined that the birds would have to hammer a tree at twice the speed they normally do to sustain any damage. The researchers also discovered something else: The bird closes its eyes upon impact, likely to avoid splinters. (More woodpeckers stories.)