Above: Woodpecker in the snow in Montreal, Quebec. Image © BalkansCat, iStockPhoto.com
Have you ever heard a woodpecker pecking? Using their beaks, these fascinating birds drill into trees to find food or to create a nest. Woodpeckers can peck a tree up to 20 times per second. They typically peck up to 12,000 pecks per day!
Did you know? A woodpecker’s tongue can be up to 3 times its length of its beak! This helps them reach bugs within trees or holes.
Pecking puts a lot of force on a woodpecker’s brain. In fact, this force is around 10 times greater than what would cause a concussion in humans. But for a long time, scientists have thought that woodpeckers don’t get headaches or concussions. Why is that?
When a woodpecker strikes a tree, the striking creates a large force on its beak. A woodpecker’s anatomy is specifically designed to absorb this force and prevent the woodpecker from getting injured. Its specialized beak and skull direct most of the energy associated with this force into the rest of its body. This protects the brain and prevents concussions or injury.
Did you know? In 2014, scientists used 3D computer models to understand how woodpeckers’ bodies distribute the force from pecking.
The woodpecker head
There are several anatomical features that protect woodpeckers. First off, woodpeckers have a bony tongue-supporting structure that starts in its mouth, wraps around its skull, and attaches between the eyes. This is called the hyoid. It acts almost like a seatbelt around the brain. The hyoid absorbs some of the energy from the collision.
Did you know? A woodpecker has a third inner eyelid which prevents the eyeball from popping out when it pecks.
The woodpecker brain
Impact injuries can happen when the brain moves around in the skull. Woodpeckers have relatively small brains which are packed very tightly inside their skulls. That means there is no space for the brain to move around in the skull and potentially get bruised.
Also, in impact injuries, the damage depends on how much area the force is being applied to. A woodpecker’s brain is oriented so that when it moves back and forth in the skull, a large area of the brain is hitting the skull. This means the force of the collision is being directed over a large surface area of the brain. This will cause less damage than if all the force was directed at a single spot in the brain. Similarly, if you were to lay on a bed of nails, you wouldn’t be hurt. But if you were to step on one nail, you would be in a lot of pain!
Also, when the brain is really small, it has a high surface area to weight ratio. This is another way that helps spread the impact force over a much larger area, causing less damage. This is not what happens in the human brain. Since our brains are larger, when we receive an impact force it causes damage to that specific area of the brain.
Woodpecker brains are also surrounded by a thick, plate-like spongy bone. This characteristic of the bone help it absorb and lessen the force of the impact.
Above: A spongy bone helps protect the woodpecker brain from the force generated by pecking.
Finally, the woodpecker always pecks its target in a direct straight line. This avoids any rotation or sheering on the brain. The anatomy is well designed so that a direct hit to the brain might not cause any damage.
Did you know? Scientists are starting to use characteristics of woodpecker heads as inspiration on how to design helmets for human heads!
So do woodpeckers never get hurt?
Unfortunately not. When it comes to getting hit or impacted due to other motions other than pecking in a straight line, woodpeckers are just as vulnerable as other birds. For example, woodpeckers are just as likely to get injured or killed from flying headfirst into a window as other birds are.
Also, thanks to recent research, scientists can’t be totally sure that woodpeckers don’t suffer any brain damage at all. According to a study published in 2018, woodpecker brains can contain a protein called tau. In human brains, tau is associated with brain damage. Scientists don’t fully understand how this protein works in human or bird brains. But this finding is a good reminder of how, in science, there are always more questions to ask!
Want to learn more about woodpeckers? Below is a narrated video of them staying organized:
Did you know? Woodpeckers actually have zygodactyl feet. This means they have two toes facing forward and two toe facing backward which allows them to have a very strong grip on the tree while they peck.
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