North America's largest woodpecker, the piliated woodpecker excels at demolishing dead trees in search for insects. One of its favourite is the carpenter ant; these large insects excavate holes in rotting trees to provide shelter for the colony. They aren't the only inhabitants of deadwood though. Many types of beetle, a variety of spiders, millipedes, and other creatures rely on these snags and fallen logs as a source of food and lodging.
It is amazing how much force a woodpecker can apply when hammering on a trunk in search of food. To really appreciate it, we can use g-force as a unit of measure. First, to understand what g-force is, you have to understand that the Earth applies 1 g-force unit upon us in the form of gravity. When you accelerate fast in a car, you get pushed backward against your seat; an aggressive acceleration may provide a g-force of 0.5. The space shuttle, during the launch phase, may hit a value of 3 g's. An F-16 jet fighter may hit 8 g's when pulling out of a dive (see the chart below, copied from
this site).
These values go through the roof when we start looking at collisions. This could be from football, hockey, or a car accident. G-forces on a person's head with values between 90-100 are enough to cause a concussion. Imagine what it would like for a woodpecker that repeatedly pounds its head against a solid surface hundreds of times a day. Scientists estimate that they are applying up to 1500 g's of force with each and every strike. How is it possible that they don't bash their brains out after the first couple of strikes?
The answer has to do with their tongue. Woodpeckers have very long tongues; some like the flicker have tongues that stick out 2 inches past the tip of their beak. Add to that the distance needed to secure the tongue and tuck it out of the way when it is not needed and you have an impressively long muscular chord. Woodpeckers keep their tongue in a sheath which wraps around the brain (see figure below, obtained from
this site). The sheath and encased tongue work together to support the brain when the woodpecker hammers on something.
In a remarkable feat of engineering, woodpeckers have devised a biological jack-hammer capable of tearing open all but the most resistant trees. It's no wonder that rotting wood, house siding, and many other substrates disntegrate under their vigilance. Although many people are annoyed by their drumming, especially during breeding season, we should all be amazed by their design. Imagine if we could harness the principles involved in their structure and apply them to car and helmet safety. The world would be a different place.
Thanks for reading.
Ericspix Eric Svendsen
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