Scientists have figured out why woodpeckers don't get brain damage.

They disproved the popular hypothesis that why woodpeckers don't get concussions when they bang their heads on wood. Previously it was believed that the structure of the skull absorbs shocks, but the researchers proved that the heads of woodpeckers are more like hard hammers, rather than protective helmets. The authors of the new study believe this is because their brains are too small. The pressure ensures the safety of the woodpecker's brain, and the force on it is below that which can lead to a concussion. However, these birds are not immune to traumatic brain injury. They can get it if, instead of wood, they mistakenly start chiseling metal.