By Chelsea Richardson
Woodpeckers hit their heads at a speed of six or seven meters per second, which is about 20 times per second, about 12,000 times a day. This is the equivalent of striking a wall at 16 mph headfirst every time.
Woodpeckers do this in order to find bugs in the wood when foods like fruit and nuts can’t be found. They also make their nests in trees by creating a hole
about eight inches wide and two feet deep. There are several factors and anatomical features that all come together to create a shock absorbent system for a woodpecker’s head.
Woodpeckers’ brains are fairly small and packed tightly in their skull, which helps prevent excessive movement of the brain. Their skull is also built to absorb shock and minimize damage with a bone that surrounds the brain that is thick and spongy. This thick, spongy material, called trabecula, is made of microscopic beam-like bits of tissue that give the bone a tightly woven “mesh” for support and protection. Researchers found that this “mesh” is located in greater amounts on the woodpecker’s forehead and at the back of the skull where it could act as a shock absorber. Their long tongue called the hyoid bone originates from the back of the jaw, passes through the right nostril, divides into two parts between the eyes, then arch over the upper portion of the skull and around the back of the head by passing on either side of the neck, coming forward through the lower jaw, and uniting into one again below the forehead. This bizarre looking bone, researchers think, acts like a safety harness for the skull and brain, absorbing shock and stress as they peck.
Woodpeckers have stout, sharply pointed beaks which help prevent trauma too. The upper beak is longer than the lower beak making a kind of overbite with the lower beak being stronger than the upper beak. Researchers believe that this diverts impact and stress away from the brain and lets the upper beak bear it instead. Their anatomy also protects the eyes. Just before their beak strikes the wood, a thick membrane found below the lower lid, sometimes called the “third eyelid”, closes over the eyes to protect them from debris and to keep them in place.
A group of Chinese scientists took a look at the woodpecker’s heads, brains, and behavior. The birds pecked at force sensors while being recorded with high speed cameras which can take up to 2,000 frames a second. They scanned their heads with x-rays and also squished preserved skulls to see how much force they could take. This study found that the woodpecker is really good at varying its pecking pattern. By moving their heads and beaks around, they minimize the number of times the brain and skull make contact in the same place. Simple reasoning would conclude that if woodpeckers got headaches, they would stop pecking.
Woodpeckers call many MNA sanctuaries home. Visit the MNA website for a list of sanctuaries across the state.