Elephants' legs 'work like wheels of 4x4s'
Elephants have legs that work like the wheels of a Land Rover, scientists have found.
The "four-leg-drive" system means power is applied independently to each limb.
All other four-footed animals are thought to be designed with "rear-leg-drive". They tend to accelerate with the hind limbs while using their forelegs more for braking.
Study leader Dr John Hutchinson, from the Royal Veterinary College, London, said: "We have developed some new techniques for looking at animal movement that may change the way that we view the locomotion of other animals.
"We have shown that elephant legs function in very strange and probably unique ways. We even overturned some of our own previous ideas about elephants, which is always initially disheartening but ultimately exhilarating for a scientist.
"Our measurements have also provided basic data that will be useful in clinical studies of elephants, such as common lameness problems."
It used to be thought that all four-legged animals divide labour between their legs, using forelegs more for braking and hind legs for acceleration.
But this was found not to be true of elephants. Measurements of forces on the animals' legs at walking and running speeds showed that each limb was used both for accelerating and braking.
Elephants' legs were also shown to be slightly compliant or "bouncy", especially when running at faster speeds.
Experts had previously assumed elephants would need rigid "pillar-like" legs to support their weight. Bounciness made their legs two to three times less mechanically efficient than expected, putting them on a par with those of humans.
Just as in humans, muscle forces in elephants have to increase as their limbs become more flexed. Consequently running is 50% more costly than walking, which is why elephants are slower than many other animals.
The scientists wrote in the journal Proceedings of the National Academy of Sciences: "Surprisingly, elephants use their forelimbs and hindlimbs in similar braking and propulsive roles, not dividing these functions among limbs as was previously assumed or as in other quadrupeds.
"Thus, their limb function is analogous to four-wheel-drive vehicles. To achieve the observed limb compliance and low peak forces, elephants synchronise their limb dynamics in the vertical direction, but incur considerable mechanical costs from limbs working against each other horizontally."
The researchers analysed the movements of six juvenile Asian elephants using an advanced 3D motion-capture technique.
Reflective markers placed at strategic points on the elephants' bodies were filmed by seven infrared cameras and their changes in position fed into a computer.
The elephants were ridden or guided by their "mahouts" across their whole range of speeds along a walkway rigged with force-sensitive platforms.
- 1 Michael Douglas regrets 'embarrassing' Catherine Zeta-Jones with oral sex comments
- 2 Tunisia hotel attack: Locals form 'human shield' to protect hotel from gunman Seifeddine Rezgui
- 3 Tunisian builder has been hailed a hero after knocking gunman to the ground with roof tiles
- 4 German ethics council calls for incest between siblings to be legalised by Government
- 5 Fifty Shades of Grey author E.L James's Twitter Q&A didn't go exactly as planned
Kim Jong-un shows off airport designed by architect he likely had executed
Michael Douglas regrets 'embarrassing' Catherine Zeta-Jones with oral sex comments
Tunisia hotel attack: Locals form 'human shield' to protect hotel from gunman Seifeddine Rezgui
Greece debt crisis: Athens has one day to find €1.6bn
German ethics council calls for incest between siblings to be legalised by Government
The moment a Queen's Guard soldier lost it and drew his gun at annoying tourist
Greece crisis: The wider lesson is that it’s time to abandon this failed experiment in currencies
'I wish the BBC would stop calling it Islamic State' – David Cameron unleashes frustration at broadcaster
Extend Right To Buy to tenants of private landlords, Labour's Jeremy Corbyn says
David Cameron struck double blow in his hopes to win Britain a new EU deal
Pentagon accuses Russia of 'playing with fire' over nuclear threats towards Nato
£15000 - £30000 per annum: Recruitment Genius: First things first - for the av...
£40000 - £60000 per annum: Recruitment Genius: A Compliance Manager is require...
£15500 - £17000 per annum: Recruitment Genius: This international company deve...
£16000 - £27000 per annum: Recruitment Genius: This established name in IT Ser...