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Elephants Do Run, Say Researchers
By Rossella Lorenzi, Animal Planet News
April 8, 2003 — Long considered among the few land vertebrates that don't run, elephants actually manage an intermediate gait that meets the biomechanical definition of running, according to a study published in the current edition of the science journal Nature.
Elephants' motion is marked by a peculiar feature: all four feet never leave the ground at the same time. This has long convinced scientists that the massive animals can't run, but a closer look revealed that they bend their knees in an unusual crouching stride pattern.
Dubbed "Groucho running" by the US researchers, after the silly bent walk of the comedian Groucho Marx, this movement technically makes them runners.
"They don't leave the ground, which is the classical definition, but they do seem to bounce, which is the biomechanical definition," first author John R. Hutchinson of Stanford University's department of mechanical engineering, said in a statement.
To study the fast motion of elephants, Hutchinson and colleagues marked the joints of 42 healthy adult Asian elephants (Elephas maximus) with large dots of white, water-soluble, non-toxic paint. Then they filmed the animals' progress over a 100-foot course, measuring their speed with photosensors and video analysis.
"Asian elephants can move at surprisingly high speeds of up to 6.8 meters per second or 25 kilometers per hour (15 mph). Although their gait might seem to be a walk even at this speed, some features of their locomotion conform to definitions of running," Hutchinson wrote.
Over 188 trials, 32 animals reached a top speed of up to 15 miles per hour, and three even exceeded that. The average speed was 10 mph.
Video analysis revealed that when the elephants sped up, their limbs contracted and they bounced, even though they always kept three feet on the ground.
The four-ton creatures used a walking footfall pattern even at 15 mph, probably because running with an aerial phase would be too mechanically stressful on their bodies, said Hutchinson.
"We are just beginning to understand which animals can break the rules and bounce without leaving the ground and how they do it," Hutchinson said.
According to animal-locomotion expert Alan Wilson of London's Royal Veterinary College, the work is "an interesting and novel study."
"It really depends on your definiton of running — in humans we use both a spring-like gait and have an aerial phase, but we only have two legs. The gait is somewhat between running and a compliant 'Groucho Marx' like walking gait.
"The elephants demonstrate some aspects of both of these criteria though since they have four legs they don't actually 'fly'," Wilson told Discovery News.
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Name: Asian Elephant ( Elephas maximus)
Primary Classification: Proboscidea (Elephants)
Location: India and Southeast Asia.
Habitat: Mainly tropical scrub forest. Also thick jungle and savannah.
Diet: Mainly grasses. Also bark, roots, leaves, fruits and stems of trees, vines and shrubs.
Size: Up to 21 feet in length, 10 feet in height and 5.5 tons in weight.
Description: Grayish to brown in color. Sparse, coarse body hair. Thick, dry skin. Long trunk with single finger-like projection. Two bumps on forehead. Columnar legs. Large, fan-like ears. Males have two long, ivory tusks.
Cool Facts: They can consume more than 500 pounds of vegetation per day. They urinate 1.5 gallons at a time and up to 15 gallons a day. They use their trunks — which contain up to 100,000 muscles — to suck and spray water, to lift heavy objects, to grasp small objects, to smell, and to detect heat and texture.
Conservation Status: Endangered
Major Threats: Habitat loss and degradation, as well as poaching.
What Can I Do?: Visit the Wildlife Conservation Society, the Elephant Help Project, and Friends of the Asian Elephant for information on how you can help.
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