By Luca Peluzzi
Woodpeckers peck their beaks into trees for several reasons: to snack on insects that have pierced under the bark, to excavate deep cavities in trees where they can nest in or to create holes in tree trunks to secretly reserve acorns. But they do it at an insane speed. The 1200–1400 G force of each peck can be 20 times greater than what would normally cause a concussion in human beings. Woodpeckers move their head at speeds up to 13 to 15 miles per hour and on average peck around 12,000 times a day, with their neck muscles and cranial bone structures protecting them.
The fact that most woodpeckers aren’t regularly knocking themselves out has led to investigating how woodpecker heads work to design new football helmets and protections that can prevent brain damages. A new study conducted on woodpecker brain tissue raises the possibility that the birds suffer from the pecks. Even if behaviourally they could seem healthy, their brains could have been damaged, as the inside protein accumulations show.
George Farah, a neurobiologist at Boston University extracted 10 woodpecker brains and sectioned them into brain slice, using five red-winged blackbirds, that do not hammer their heads against trees, as control samples. Farah stained the tissue with molecules of silver, an element that ties with high specificity to a protein called tau. This protein is normally contained in nerve cells, but after an injury it changes its form and cluster in toxic accumulation.
In human brains, these tau toxic aggregations suggest the presence of the chronic traumatic encephalopathy (CTE), a disease that involves aggression, memory loss, confusion and depression, and it can eventually lead to dementia. Autopsies of former NFL players have found that those who suffered from chronic traumatic encephalopathy symptoms also had significant build-ups of tau protein in their brains.
While none of the red-winged blackbirds showed tau accumulation, eight of the ten woodpeckers did, Farah and his colleagues Peter Cummings and Don Siwek wrote in an article published in the journal PLOS One.
However, it doesn’t mean the woodpeckers are brain-damaged. It’s not clear how much tau can be accumulated in a woodpecker brain before the bird starts behaving abnormally or if the tau presence is a sign of good adaptation. In fact, tau in woodpecker brains could be an adaptation for dealing with trauma or the birds could have developed ways of dissolving excess accumulations of the protein. Further study is needed, even because woodpeckers brains are smaller and significantly different from human ones and this can change many mechanisms. The former have a hyoid bone that wraps around the skull and may act as a seatbelt for the skull, they are in tighter spaces inside the skull and do not move around as much as the human brain does in our skull.
A better understanding of woodpecker brains could help to figure out how other head-banging animals protect themselves from brain trauma and perhaps improve the protection of vulnerable National Football League or other sports players.