Pourquoi les pics n’ont-ils pas mal à la tête ?

The drumming of Woodpeckers is familly specific and may be used for communication or territorial display, but is not related to feeding.
As a result of these activities, Dryocopus pileatus may strike the hard woody surface of a tree at a rate of up to 20 times a second (not a misprint) and up to 12 000 times a day with staggering deceleration forces of as high as 1200 g with each impact. That is equivalent to striking a wall at 16 miles an hour-face first-each time.
When your daily routine involves slamming your head against a tree as it is the case for Woodpeckers, you might expect to get an occasional headache. However, they experience no ill effects from their head-banging ways and, for explaining why, UC Davis ophthalmology professor Ivan Schwab was chosen for the 2006 Ig Nobel Prize in ornithology. He received the award at Harvard University. He shared the prize with the late psychiatrist Phillip R.A. May, whose previous research formed the basis for the study written by Schwab.
Schwab has a special interest in comparative ophthalmology, a field in which he and others examine how insects, birds, reptiles and other nonhuman animals process images.
In his research, May found that woodpeckers have evolved several unique mechanisms that prevent them from inflicting harm upon themselves. Among them are a thick, bony skull with relatively spongy bone, and cartilage at the base of the mandible (lower jaw bone) that partially cushions the incessant blows. The mandibles are attached to the skull by powerful muscles that contract a millisecond before each strike, creating a tight but cushioned structure at the moment of impact and distributing the force of the blow to the base and posterior regions of the skull, thus bypassing the brain.