Here is in my taste one of the most interesting pubs in Physics Today in 2024
Не болит голова у дятла:
https://pubs.aip.org/physicstoday/artic ... ontrary-to
Initially, it was thought that it is due to shock absorbing effects of a porous zone of spongy bone at the front of a woodpecker’s brain. The idea was supported by 3D Computer Tomography that became available in the 1970s. It even inspired the design of new shock-absorbing materials and helmets.
Although , psychiatrist Philip May got quickly self-critical of the idea , reasonably arguing that if the shock absorber really works so well - it would work both ways. So unfortunate birds would have to pound even harder to get food in trees steams. Nonetheless, May and ophthalmologist Ivan Schwab, were awarded the 2006 Ig Nobel Prize in Ornithology for his work.
The truth is actually much simpler. The keys to the birds’ ability to withstand high decelerations include their small size. The intracranial pressure developing during a crush deceleration is roughly proportional to the impact force divided by the brain cross section area , which is the product of the bird’s deceleration, the mass density of its brain tissue, and the brain length (or volume/area).
Btw, it explains , why no giant woodpeckers exist ( and never existed - even in the dinosaur era) that could drill holes much deeper than those drilled by currently living small species.