No one knows just how many American football players walk away from the sport with a permanent type of brain damage known as CTE. But new research on woodpeckers could lead to long-term prevention therapies.
It would be a cruel trick of evolution if woodpeckers could develop brain damage just by pecking wood.
But new research from the US shows that the high-force impacts do cause a potentially harmful protein to build up inside brains of downy woodpeckers.
That protein is a type of "tau," and it is the same kind found inside the brains of people with neurodegenerative diseases like Alzheimer's or Parkinson's. It is also found inside the brains of some athletes who played high-impact sports like American football, rugby or hockey.
In woodpeckers, the presence of this tau protein is odd because it would seem to suggest that the bird's own body has not evolved to protect itself from a daily routine - chipping a hole into a tree - which it does to forage for food, a nest or sexual advantage.
A study in 15 birds
For their study, scientists at Boston University examined the brains of ten downy woodpeckers and compared them to the brains of five control birds that don't engage in any comparable high-impact pecking behavior, in this case red-winged black birds.
Under the microscope, zero of the five control birds showed tau "stains" indicating brain damage.
When the downy woodpeckers were examined, eight out of ten did.
That suggests the forceful decelerations of their skull against a tree are causing real damage to their brains - or at the very least is leading to the creation of a potentially harmful protein.
The presence of these tau clumps has opened the question as to whether they're pathological in the birds or whether they are neutral or even protective in nature.
A comparison of a healthy human brain and one with Level 4 CTE
Answering that question could be relevant toward preventing or treating Chronic Traumatic Encephalopathy, or CTE, which develops after multiple head injuries and can lead to behavioral changes and long-term dementia. Boston University researchers recently found CTE lesions in the brains of 110 of 111 deceased former NFL players, but such lesions are also suspected to occur in other high-impact sports.
And since the tau stains were also discovered in a juvenile woodpecker, the researchers suspect that age may be a less relevant factor than repetitive impact trauma to the brain.
The study published in PLOS ONE is the first of its kind to look at the potential existence of neurotrauma in woodpeckers. With their thick necks and unique skulls, the birds had previously been considered so evolutionarily adapted to pecking that they were used as models for safety equipment such as American football helmets and neck collars.
The research also lends a bit of prescience to the 1979 poem "Woodpecker" by English poet and children's writer Ted Hughes:
Woodpecker is rubber-necked
But has a nose of steel.
He bangs his head against the wall
And cannot even feel.
When Woodpecker’s jack-hammer head
Starts up its dreadful din
Knocking the dead bough double dead
How do his eyes stay in?
Pity the poor dead oak that cries
In terrors and in pains.
But pity more Woodpecker’s eyes
And bouncing rubber brains.