MAY 05, 2016 05:13 AM PDT

Peck away: the science behind woodpeckers' brains

One would think that aggressively knocking your head against a hardwood tree would result in a few minor concussions at the very least. However woodpeckers, who are known for such vigorous actions, are apparently immune to such brain damage. MIT Professor Lorna Gibson, a MacVicar Fellow and the Matoula S. Salapatas Professor of Materials Science and Engineering, set out to find out why this was. In doing so, she collaborated with MITx, the Institute’s collection of free, online courses, and created a series of eight videos depicting the science behind woodpeckers brains and physiology.

One previous theory to Gibson’s research was that woodpeckers have a foam-like material between their brain and their skull. However, after a group of neurologists in California dissected the head of a dead woodpecker and failed to find any spongy substance, this theory was rejected. Gibson then became even more interested in the physiology of woodpeckers.

In the video series , Gibson explains that woodpeckers peck to forage for food (insects and sap), build nests, attract mates, and even store food (for certain acorn woodpecker species). Gibson also discusses some of the adaptations that the birds have for these pecking purposes. In order to apply enough force to chip away pieces of wood, the birds use their tails to brace themselves again trees - they have particularly large, thick shafts in their tail feathers to help them with this. They also have two toes facing forward and two toes facing backward (instead of the normal 3 and 1 orientation of birds) to help brace themselves for more force.
The orientation of woodpeckers' toes helps them to exert high forces

To measure the forces that woodpeckers apply and these impacts on their brains, one needs to determine the acceleration that the bird’s head experiences as it prepares to hit the tree as well as the deceleration that it experiences upon actually hitting the tree. With some high tech video footage, scientists found that woodpeckers experience a deceleration of 600g-1500g with every peck. This may not mean much until you think about that humans experience brain injury with only 100g. Furthermore, the birds can peck trees with a speed of up to 15 mph; if you were to ride your bike into a tree at that speed over and over again, your body and brain would definitely not be happy. So how do the birds do it?
The Red-bellied woodpecker's name deceives it, as there is not actually much red on its breast

“It turns out it’s all a matter of scale,” says Gibson, “and the smaller the brain, the larger the deceleration it can withstand.” This is called a scaling law.  It also depends on the duration of the impact, which for woodpeckers is between 0.5-1 millisecond - so short that it allow the birds to tolerate a higher impact.
“Gibson notes that other factors that contribute to protecting the brain of the woodpecker. As opposed to the human brain, which has space and fluid between the brain and the skull, the woodpecker’s brain has very little cerebrospinal fluid and is tightly packed in the skull, which Gibson says “reduces the motion of the brain within the skull on impact and reduces the effect of shock waves transmitted through the fluid.”
 

 
?Sources: MIT Slice
About the Author
  • Kathryn is a curious world-traveller interested in the intersection between nature, culture, history, and people. She has worked for environmental education non-profits and is a Spanish/English interpreter.
You May Also Like
JUN 28, 2018
Earth & The Environment
JUN 28, 2018
How the weed industry is killing off California's wildlife
The marijuana industry is pushing several endemic species into threat, and at the top of the list is the cute but savage Humboldt marten. The Center for Bi...
JUL 25, 2018
Plants & Animals
JUL 25, 2018
Do Lizards Respond to Hurricanes With Rapid Natural Selection?
Do hurricanes induce rapid natural selection in tropical lizard populations? That's the latest idea that Harvard University researchers are bearing in mind...
AUG 01, 2018
Plants & Animals
AUG 01, 2018
Lemur Populations in Serious Trouble, IUCN Says
Citing animal conservationists employed by the International Union for Conservation of Nature (IUCN), at least 95% of the world’s lemur populations f...
AUG 20, 2018
Plants & Animals
AUG 20, 2018
Worker Ants Intelligently Regulate Tunnel-Digging Efforts to Avoid Jams
At first glance, any burrows look just like tiny dirt mounds on the ground. But just beneath these inconspicuous little mounds are complex mazes comprised ...
SEP 12, 2018
Plants & Animals
SEP 12, 2018
Global Turtle Decline Adversely Impacts the Surrounding Ecosystem
The Earth is home to a wide assortment of turtle species, but many populations continue to decline despite rigorous conservation efforts that are intended...
SEP 20, 2018
Earth & The Environment
SEP 20, 2018
Biodiverse forests are more resilient to drought
Biodiversity is confirmed yet again to be a savior for vulnerable species. In a new study published in Nature, scientists determined that forests with more...
Loading Comments...