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. They publish their results on 12 February 2010 in The Journal of Experimental Biology at http://jeb.biologists.org.
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.
Heglund explains that the elephant's cost of transport is low because the animal's step frequency is higher than expected and they improve their stability by keeping an average of two feet on the ground even at high speeds, and three at lower speeds. Combining these approaches, the elephant's centre of mass bounces less than other animals', reducing the giant's cost of transport.
Next the team calculated the way that each animal recycles potential energy into kinetic energy to find out whether they run. According to Heglund, running animals continually recycle potential energy stored in tendons and muscles into bouncing kinetic energy – just like a pogo stick – while walking animals convert potential energy at the start of a stride into kinetic energy as they step forward – much like an inverted swinging pendulum. By tracking how elephants cycle potential energy into kinetic energy over the course of a stride, the team could distinguish whether the high-speed animals were running or walking.
Plotting the potential and kinetic energy of the elephants' centres of mass over the course of many strides at different speeds, the team could see that the elephants were walking like an inverted pendulum at low speeds, but as they moved faster, the kinetic and potential energy plots shifted to look like those of runners. However, when the team analysed the movements of the elephant's centre of mass, they could see that it almost maintained a constant level as the animal shifted its weight from one side to the other, but bobbed down and up like a runner's during the second half of the stride.
So the elephants were running by one measure but not by another and it seems that the forelimbs trot while the hind limbs walk at higher speeds. 'High-speed locomotion in an elephant doesn't fall nicely into a classic category like a run or a trot. It really depends on your definition of "run",' says Heglund.
IF REPORTING ON THIS STORY, PLEASE MENTION THE JOURNAL OF EXPERIMENTAL BIOLOGY AS THE SOURCE AND, IF REPORTING ONLINE, PLEASE CARRY A LINK TO: http://jeb.biologists.org
Genin, J. G., Willems, P. A., Cavagna, G. A., Lair, R. and Heglund, N. C. (2010). Biomechanics of locomotion in Asian elephants. J. Exp. Biol. 213, 694-706.
This article is posted on this site to give advance access to other authorised media who may wish to report on this story. Full attribution is required, and if reporting online a link to jeb.biologists.com is also required. The story posted here is COPYRIGHTED. Therefore advance permission is required before any and every reproduction of each article in full. PLEASE CONTACT email@example.com
Gene therapy shows promise for treating Niemann-Pick disease type C1
27.10.2016 | NIH/National Human Genome Research Institute
'Neighbor maps' reveal the genome's 3-D shape
27.10.2016 | International School of Advanced Studies (SISSA)
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Life Sciences
27.10.2016 | Life Sciences
27.10.2016 | Power and Electrical Engineering