How the woodpecker avoids brain damage: Unique anti-shock body structure absorbs 99% of impact energy
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The woodpecker's brain can withstand repeated collisions when it rapidly pecks at a tree looking for food - and now scientists think they know why.
The bird avoids brain injury, despite the repeated high-speed impacts, because of the unique structure of its skull and beak, which reduces the impact on the brain.
Chinese scientists have found that its body stores 99 per cent of energy from impacts as strain energy - the energy stored by an object which changes temporarily because of an applied force.
The woodpecker avoids brain injury - despite the repeated impacts sustained by pecking at trees - because of the structure of its skull and beak, which reduces the impact on the brain. Scientists measured the stress at different times during pecking. (a) and (e) are moments of readiness to peck, (b) and (d) are moments of departure and return and (c) marks the moment of collision. Arrows on the beaks show velocity direction. It is clear the high levels of impact (shown in red) spread though the bird's body after a collision
WHY ARE SCIENTISTS INTERESTED IN WOODPECKERS?
Experts are interested in how the woodpecker protects its brain and body from shock and vibrations because it could help develop anti-shock devices and structures, which could be used in next-generation, spacecraft, cars and protective clothing.
Dr Wu from the Dalian University of Technology said that spacecraft face the constant danger of collisions with space debris, which can be expensive and can put lives at risk.
Scientists could design anti-shock materials inspired by the structure of a woodpecker, to dissipate the energy created by an impact from one spot and spread it across a larger area to reduce damage.
New materials could also make car crashes less violent, which could reduce the number of people suffering severe head injuries in collisions.
Experts are interested in how the woodpecker protects its brain and body from shock and vibrations because it could help develop anti-shock devices and structures, which could be used in next-generation, spacecraft, cars and protective clothing.
Engineers at the State Key Lab of Structural Analysis for Industrial Equipment, which is part of the Department of Engineering Mechanics at the Dalian University of Technology in north eastern China, found that the woodpecker's body works as an excellent anti-shock structure by absorbing energy from impacts.
Woodpeckers can peck trees at a high frequency – up to 25Hertz - and at high speeds equivalent to seven metres per second without suffering any brain injury.
The force of the bird's pecking is equivalent to 1,000 times the force of gravity - the same as a human striking their head against a wall at a speed of 16 miles (25km) an hour with each peck.
Woodpeckers (pictured) can peck trees at a high frequency - up to 25Hz - and at high speeds without suffering any brain injury
In the study, scientists made 3D computer models of a woodpecker and used programmes to understand how its anti-shock body structure distributes the energy from impacts.
Dr Wu Chengwei and his team used CT scans of the bird to build their 3D computer model.
'Based on the CT scanning technology, detailed inner structure images of the head were obtained and then imported to Mimics software to form a scattered-points model,' they explained.
More programmes were used to finish the geometric model, which was used to test how impact energy was handled by its specially adapted structure.
'Most of the impact energy in the pecking is converted into the strain energy stored in the body (99.7 per cent) and there is only a small fraction of it in the head (0.3 per cent),' the researchers said.
Structures in the head included the beak and the the hyoid bone which further reduce the strain energy of the brain.
The small fraction of impact energy that enters the brain will eventually dissipate in the form of heat, causing a rapid temperature increment in the brain.
This is why the woodpecker has to peck intermittently and take short breaks.
The findings of the study, published in the journal Science China Technological Science, could be used to design anti-shock devices and structures, which could be used in next-generation, spacecraft, cars and protective clothing.
'High-speed impacts and collisions can destroy structures and materials,' Dr Wu said.
'In the aerospace industry, spacecraft face the constant danger of collisions with space debris and micrometeoroids.'
'If a spacecraft's structure or scientific instruments were destroyed by impact, the economic loss would be huge.'
'In cities worldwide, car accidents are a persistent threat to human safety and head injuries are common so there is a real need for new anti-shock materials.'
Experts are so interested in how the woodpecker protects its body from shock and vibrations, so they can learn lessons from nature in order to design better cars, for example, that can endure high-velocity impacts. A stock image of a car accident is pictured
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