How woodpeckers avoid head injury Skip to main content

How woodpeckers avoid head injury

BBC



This slow-motion footage reveals the woodpecker's head-banging antics in detail

Related Stories

Slow-motion footage, X-ray images and computer simulations have shed light on how woodpeckers avoid injuries to their brains as they peck.

Their heads move some 6m per second, at each peck enduring a deceleration more than 1,000 times the force of gravity.

But researchers reporting in Plos One say that unequal upper and lower beak lengths and spongy, plate-like bone structure protect the birds' brains.

The findings could help design more effective head protection for humans.

For years, scientists have examined the anatomy of woodpeckers' skulls to find out how they pull off their powerful pecking without causing themselves harm.

The birds have little "sub-dural space" between their brains and their skulls, so the brain does not have room to bump around as it does in humans. Also, their brains are longer top-to-bottom than front-to-back, meaning the force against the skull is spread over a larger brain area.

A highly-developed bone called the hyoid - which in humans gives the "Adam's apple" - has also been studied: starting at the underside of the birds' beaks, it makes a full loop through their nostrils, under and around the back of their skulls, over the top and meeting again before the forehead.

Head-banging study
 
However, Ming Zhang of the Hong Kong Polytechnic University, a co-author of the new work, said that he and his colleagues wanted to get to the bottom of the problem numerically.

"We thought that most of the previous studies were limited to the qualitative answer to this question," he told BBC News.
Woodpecker skull simulation  
The simulations show precisely how forces are distributed in the birds' skulls
"More quantitative studies are necessary to answer this interesting problem, which would aid in applying the bio-mechanism to human protective device design and even to some industry design."

First, the team had a look at woodpeckers in a controlled environment: two slow-motion cameras captured images of the birds striking a force sensor that measured their pecking power.

They found that the birds slightly turn their heads as they peck, which influences how forces are transmitted.

The team also gathered computed tomography and scanning electron microscope analyses of woodpecker skulls, laying out in detail how the parts fit together and where bone density varied.

With those data in hand, they were able to use a computer simulation to calculate the forces throughout the birds' skulls in the process of pecking.

The team's simulations showed that three factors were at work in sparing the birds injury.
Firstly, the hyoid bone's looping structure around the whole skull was found to act as a "safety belt", especially after the initial impact.

The team also found that the upper and lower halves of the birds' beaks were uneven, and as force was transmitted from the tip of the beak into the bone, this asymmetry lowered the load that made it as far as the brain.

Lastly, plate-like bones with a "spongy" structure at different points in the skull helped distribute the incoming force, thereby protecting the brain.

The team stresses that it is the combination of the three, rather than any one feature, that keeps woodpeckers pecking without injury.

Comments

Popular posts from this blog

Chronology of the Press in Burma

1836 – 1846 * During this period the first English-language newspaper was launched under British-ruled Tenasserim, southern  Burma . The first ethnic Karen-language and Burmese-language newspapers also appear in this period.     March 3, 1836 —The first English-language newspaper,  The Maulmain Chronicle , appears in the city of Moulmein in British-ruled Tenasserim. The paper, first published by a British official named E.A. Blundell, continued up until the 1950s. September 1842 —Tavoy’s  Hsa-tu-gaw  (the  Morning Star ), a monthly publication in the Karen-language of  Sgaw ,  is established by the Baptist mission. It is the first ethnic language newspaper. Circulation reached about three hundred until its publication ceased in 1849. January 1843 —The Baptist mission publishes a monthly newspaper, the Christian  Dhamma  Thadinsa  (the  Religious Herald ), in Moulmein. Supposedly the first Burmese-language newspaper, it continued up until the first year of the second Angl

ARSA claims ambush on Myanmar security forces

Arakan Rohingya Salvation Army (ARSA) on Sunday claimed responsibility for an ambush on Myanmar security forces that left several wounded in northern Rakhine state, the first attack in weeks in a region gutted by violence. Rakhine was plunged into turmoil last August, when a series of ARSA raids prompted a military backlash so brutal the UN says it likely amounts to ethnic cleansing of the Muslim Rohingya minority. The army campaign sent some 650,000 Rohingya fleeing for Bangladesh, where refugees have given harrowing accounts of rape, murder and arson at the hands of security forces and vigilantes. Myanmar's military, which tightly controls information about Rakhine, denies any abuses and insists the crackdown was a proportionate response to crush the "terrorist" threat. ARSA have launched few attacks in recent months.  But the army reported that "about ten" Rohingya terrorists ambushed a car with hand-made mines and gunfire on Friday morning

Thai penis whitening trend raises eyebrows

Image copyright LELUXHOSPITAL Image caption Authorities warn the procedure could be quite painful A supposed trend of penis whitening has captivated Thailand in recent days and left it asking if the country's beauty industry is taking things too far. Skin whitening is nothing new in many Asian countries, where darker skin is often associated with outdoor labour, therefore, being poorer. But even so, when a clip of a clinic's latest intriguing procedure was posted online, it quickly went viral. Thailand's health ministry has since issued a warning over the procedure. The BBC Thai service spoke to one patient who had undergone the treatment, who told them: "I wanted to feel more confident in my swimming briefs". The 30-year-old said his first session of several was two months ago, and he had since seen a definite change in the shade. 'What for?' The original Facebook post from the clinic offering the treatment, which uses lasers to break do