A Woodpecker Skull
The New York Times features a piece about the adaptations of the skulls of animals prone to head banging, such as woodpeckers, that help prevent traumatic brain injury.
The brains of most animals that are prone to head banging — these include deer and other antlered mammals, as well as various birds — are relatively small and (unlike a human’s) smooth-surfaced; and they’re bathed in only small amounts of cerebrospinal fluid, leaving little room for the brain to move and be shocked by the sudden decelerations and accelerations of their weaponized heads.
Moreover, both rams and woodpeckers are scrupulous in the precise, single-direction fashion in which they smash their heads into things, whether trees or one another: The aim is such that there’s very little side-to-side torsion exerted on the brain, none of the movement that induces whiplash injury and other kinds of damage.
Not new revelations, as research into the subject has made the rounds in the news before. Even this year. Hell, even within species, skull thickness and other variations may play a role in how susceptible we are to traumatic brain injury.