Lumbering pachyderms almost as mobile as horses: StudyAugust 23rd, 2008 - 6:00 pm ICT by IANS
London, Aug 23 (IANS) In popular perception, playful pachyderms are perceived as stiff gaited, but latest research has established that they are almost as mobile as trotting horses.For example, John Hutchinson of The Royal Veterinary College visited several zoos in Britain and had even been to Thailand to study how Asian elephants moved their legs as they walk and run.
Keepers of Colchester and Whipsnade Zoos in Britain were keen to know more about the animals’ natural limb movements in order to develop training programmes and prevent the onset of arthritis.
Luckily, Hutchinson found the animals extremely cooperative when he turned their exercise enclosure into a film set to record their movements. “This is the same 3D capture technology used in Hollywood blockbusters,” Hutchinson explained.
The pachyderms were happy to walk and run in front of the arc of infrared detecting cameras as Hutchinson and his team filmed their steps at speeds between 0.62 metres per second to 4.92 metres per second.
“The big problem was keeping the markers in place,” said Hutchinson, adding: “The little ones kept on pulling them off with their trunks.”
Having filmed animals weighing between 521 kg and 3,512 kg, Hutchinson, Lei Ren and Charlotte Miller travelled to Thailand to film the athletic Thai racing elephants that easily outpaced their British counterparts at 6.8 metres per second.
Back in the lab, Ren converted each elephant’s movements into stick figures, and found that their legs are not as columnar as previously thought, with the shoulder, hip, knee and elbow joints flexing significantly.
As the elephants swung their front legs forward they also flicked their feet up, bending their wrists by more than 80 degrees, to keep them clear of the ground.
Meanwhile, the elephants’ ankles were far more rigid. Unable to bend the ankle as they swung their legs, the animals moved them out in an arc, to avoid dragging their hind feet along the ground.
However, it was a different matter when the team analysed their joints during the stance phase; the apparently rigid ankle was relatively spring-like, whilst the previously flexible wrist became rigid while supporting the animal’s weight.
Hutchinson also compared his Asian elephant data with Delf Schwerda and Martin Fischer’s data from African elephants: the two species were indistinguishable.
Most surprisingly, when Heather Paxton investigated the maximum swing range of each joint, she found that elephants were using almost all of their mobility range.
And when the team compared the elephants’ movements with those of horses, they found that the elephants’ joints were almost as mobile as trotting horses’.
Best of all, when Hutchinson compared the athletic Thai elephants with their more sluggish British cousins, their movements were essentially the same. Captivity had not modified the elephants’ mobility range, just slowed them down a little.
“The keepers were very pleased,” Hutchinson said.
The results were published in The Journal of Experimental Biology.