Are High Speed Elephants Running Or Walking?
Most animals don't think anything of breaking into a run: they switch effortlessly from walking to a high-speed bouncing run. But what about elephants?
Their sheer size makes it impossible for them to bounce up in the air at high speeds. So how are high-speed elephants moving: are they running or walking?
At a first glance, fast-moving elephants look as if they are walking, according to John Hutchinson from the Royal Veterinary College, UK. But closer analysis of elephant footfall patterns by Hutchinson suggested that speedy elephants' front legs walk while their hind legs may trot.
Norman Heglund from the Université catholique de Louvain, Belgium, realised that the only way to resolve the conundrum was to measure the immense forces exerted on the animals by the ground as they move and found that elephants run in some senses, but not in others.
To measure these forces, Heglund had to construct and calibrate an 8m long, elephant-sized force platform from sixteen 1m2 force plates. Crating the 300kg force plates, cameras and computers in Belgium and shipping the equipment to the Thai Elephant Conservation Centre in Lampang, Thailand, Heglund, Joakim Genin, Patrick Willems, Giovanni Cavagna and Richard Lair built a reinforced concrete foundation and assembled the force platform ready to measure the enormous ground reaction forces generated by the animals.
Encouraged to move by their mahouts, 34 elephants ranging from an 870kg baby up to a 4 tonne adult moved over the force platform at speeds ranging from a 0.38m/s stroll to a 4.97m/s charge.
Based on the force measurements, the Belgian team was able to reconstruct the movement of each animal's centre of mass and found that the elephant's movements are extremely economical. Consuming a minimum of 0.8J/kg/m, an elephant's cost of transport is 1/3 that of humans and 1/30 that of mice.
"Young African Elephant leaving a waterhole in the Savute/Savuti area of Chobe N.P. in Botswana. Most animals don't think anything of breaking into a run: they switch effortlessly from walking to a high-speed bouncing run. But what about elephants? Their sheer size makes it impossible for them to bounce up in the air at high speeds. So how are high-speed elephants moving: are they running or walking? (Credit: iStockphoto/Liz Leyden)"
Source: The Company of Biologists
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