Woodpecker pecking: how woodpeckers avoid brain injury

Woodpeckers are capable of repeated pecking on a tree at remarkably high decelerations (on the order of 10 000m s 2 or 1000 g). In this paper, I re-examine previous studies of pecking and scaling effects in brain injury. I find that there are three keys to woodpeckers’ ability to withstand high decelerations: their small size, which reduces the stress on the brain for a given acceleration; the short duration of the impact, which increases the tolerable acceleration; and the orientation of the brain within the skull, which increases the area of contact between the brain and the skull.