Woodpecker research flies away with alternative prize.
When Ivan Schwab first learned that he was slated to win an Ig Nobel prize for explaining why woodpeckers don't get headaches, his response was perhaps predictable for a man whose past had come back to haunt him: he denied everything.
“I didn't do the work,” Schwab, an ophthalmologist at the University of California, Davis, told the event's organizer after being informed of the dubious honour in store for him. Ig Nobel prizes are given for “achievements that make people laugh, and then make them think”. Schwab gave credit instead to Philip May, a former psychiatry professor at the University of California, Los Angeles, who died in 1986. A deal was soon reached: Schwab agreed to share the 2006 Ornithology prize with May for research initiated by May and associates in 1976 and taken up by Schwab a quarter of a century later.
To May, the woodpecker represented a unique “experiment in Nature” and a chance to understand how an animal could continually use its head as a battering ram without sustaining headaches, concussions or other brain injuries.
A pileated woodpecker may strike its beak against a tree 12,000 times a day for the purposes of feeding, nest construction, ritual drumming (to claim territory and attract mates), and even to relieve tension. They peck at rates of up to 20 times a second — each blow is comparable to striking a wall, face-first, at 25 kilometres an hour. This results in deceleration forces of about 1,200g, which is hundreds of times more than astronauts endure. Given the ill effects of headbanging seen in humans, May wondered why the countryside was not “littered with dazed and dying woodpeckers”.
Clearly, woodpeckers do not get headaches or serious head injuries, May reasoned, or they would stop pecking. So how do they prevent it? After dissecting the heads and beaks of two woodpeckers (which were compared with similar toucan samples) and analysing high-speed photographs of live woodpecker strikes, May and his colleagues advanced several explanations (P. R. May et al. Lancet i (7957), 454–455; 1976; Arch. Neurol. 36, 370–373; 1979).
The woodpecker brain has relatively little cerebrospinal fluid, reducing the transmission of shock waves, and it is tightly packed in dense, spongy bone that keeps internal movements to a minimum. Muscles encircling the skull serve as shock absorbers, “holding the bill in resilient rigidity”.
Like boxers, woodpeckers tense their neck muscles before absorbing a blow. And their drilling trajectory is essentially linear, with little or no rotation of the head, to avoid shearing forces. A third eyelid closes a millisecond before each strike to secure and shield the eye.
Schwab, a bird enthusiast since childhood, read May's 1976 Lancet article and later papers with keen interest. On occasion, he mentioned the woodpecker example in ophthalmology classes and at conferences, citing the potential for retinal damage, and always engaged his audience. Yet he yearned to do more on the subject.
He got his chance in 2000, when he became an editor of the British Journal of Ophthalmology. In 2002, Schwab put a woodpecker on the journal's cover and wrote an essay presenting May's findings and discussing anatomical features that might provide further protection, as a result of dissections and CT scans he had performed of a pileated woodpecker head (I. R. Schwab Br. J. Ophthalmol. 86, 843; 2002).
But Schwab's main objective was to bring attention to May's neglected work. “We can't all win Nobel prizes,” he says. “But we can look at the world around us and ask questions, just as May did.” In his own field, Schwab asks, for example, why polar bears don't get ultraviolet keratopathy — sunburn of the eyes. How can a jellyfish, which lacks a brain, process the visual information it gets from its eyes? Why do scallops have hundreds of eyes and giant clams thousands? Questions such as these, says Schwab, are “the basis of discovery”.
For that reason, Schwab says he is proud to be associated with May's research and was delighted to receive an Ig Nobel on his behalf at the ceremony held at Harvard University on 5 October (see 'The Ig Nobel winners' circle'). He certainly got into the spirit of things, attending the festivities in a woodpecker headdress. As for his initial reluctance, Schwab explains: “I was embarrassed to receive an Ig Nobel prize for work I did not do.” In that respect, he stands out from previous winners, who were embarrassed to receive Ig Nobels for work they did do.
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Science China Life Sciences (2013)