March 30, 2010 | David F. Coppedge

Elephants Equipped with 4WD

An elephant is built like a four-wheel drive vehicle, say scientists from the Royal Veterinary College in London.  Unlike other mammals, which divide acceleration and braking between the front and rear legs, “power is applied independently to each limb,” reported PhysOrg from a paper in PNAS.1
Elephant limbs operate analogously to four-wheel-drive vehicles,” the authors stated unabashedly in their paper.  “Although the four limbs share qualitatively equivalent mechanical functions (i.e., their contributions to braking and propulsion are proportionately similar, not skewed toward one or the other), elephant locomotor mechanics are dominated by the forelimbs, which do more work and contribute more power to the CoM [Center of Mass].”
The benefits of independent leg control come at the cost of lower effective mechanical advantage, requiring more energy at higher speeds, the authors explained.  That’s why elephants do not run very fast for very long.  Another study published by the University of Manchester last fall, however, said counterintuitively that “Large, lumbering animals such as elephants move much more efficiently than small, agile ones such as mice” (see PhysOrg).  In fact, contrary to man-made vehicles, “bigger animals move three and a half times more efficiently than smaller ones.”  This comes from having upright posture and more spring in the step.
The reduced mechanical advantage from four-leg drive needs to be seen in context.  Another study reported by Royal Veterinary team last month in PhysOrg said that an “elephant’s movements are extremely economical.”  They compared it to mice and men:2 “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.
They also examined whether elephant locomotion at higher speeds is best described as walking or running.  It’s both, depending on the definition.  They observed that, running or walking, elephants keep a remarkably even keel.  Watch an elephant’s shoulder next time you see one at a trot.  The scientists measured this, and found that “the elephant’s centre of mass bounces less than other animals’, reducing the giant’s cost of transport.
From the baby elephant walk to the bull run, the gait of the elephant appears well designed for its four ton bulk.  None of the papers said anything about how this independent leg control might have evolved.  The PNAS paper, however, made one astonishing admission about evolution.  The authors essentially said that a contradiction to evolutionary expectations was somehow due to evolution anyway: “Functional equivalence of all four limbs is in contradiction to our previous findings, which assumed some functional similarity between the limbs of elephants and other mammals.  This equivalence seems to be a unique specialization of elephants that relates to their unique size, range of habitats, and evolutionary history.”  That statement did not include any references to evidence of fossil transitional forms going from rear-leg to four-leg design.

1.  Ren, Miller, Lair and Hutchinson, “Integration of biomechanical compliance, leverage, and power in elephant limbs,” Proceedings of the National Academy of Sciences, published online March 29, 2010, doi: 10.1073/pnas.0911396107.
2.  Recall from the 11/18/2004 entry that human anatomy is remarkably well adapted for distance running.

That lone reference to evolution was disgusting.  Did you catch that?  They used zero evidence to support evolution.  (Again.)  If unique traits can be attributed to “evolutionary history” as much as homologous traits can, Darwin has rigged a scam.  It’s the old heads-I-win-tails-you-lose trick.
If anything, elephants have devolved.  The fossil record shows larger, more powerful members of the elephant family – the wooly mammoths, and several other robust behemoths no longer with us.  We can appreciate the design of the sport utility vehicles still around, and only wonder at the humvees and tanks of the past.  And just imagine the power of the dinosaurs, like the gigantic Titanosaurs.  The Creator knew how to move a lot of mass around with efficiency and grace; after all, he created the laws of physics, too.

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Categories: Amazing Facts, Mammals, Physics

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