Big leap: Elephants, rhinos too big to jump

Q. Is it true that elephants are the only quadrupeds that cannot jump? –S. Bubka
A. Elephants can't jump from ground level anyway, nor can turtles or large crocodiles; even hippos probably can't or don't, says Royal Veterinary College, London, biomechanics expert John R. Hutchinson in New Scientist magazine.

"However, the truth is no research has looked at this question in a rigorous way, just scattered anecdotes and folklore, like the tired myth that elephants have four knees (they actually have two)," Hutchinson says.

University of Leeds zoologist R. McNeil Alexander notes that racehorses weighing about half a ton are among the largest quadrupeds that can make impressive jumps, such as the highest fence on the Grand National course at 1.8 meters (6 feet) high. But whether an elephant or hippopotamus can jump depends on the definition used.

"A film I took of a white rhino galloping showed that all four feet were off the ground at once,” Alexander writes. “I don't think of that as jumping, but I can't think of any clear-cut definition of jumping that would exclude it."

Really heavy animals can hardly jump or land without injury, notes Jon Richfield of Somerset West, South Africa.

So, don't jump to conclusions if a large animal chases you over a ditch: "J.H. Williams in his book Elephant Bill relates how a stampeding female rhino jumped a ditch handily, though she went lame in both forefeet soon after," Richfield says.

Q.Do heavier or lighter ski jumpers jump farther? –J.-C. Killy
A. Even though heavy ski jumpers accelerate faster downhill and thus achieve greater takeoff speeds, lighter jumpers rise much higher into the air and enjoy longer glides, says magazine. All things considered, light ski jumpers have the advantage.

To verify this, researchers at the University of Graz in Austria used computer simulations and wind-tunnel testing, varying parameters such as downhill and takeoff speeds, angles, air resistance, and lift– all of them affected by a skier's weight.

Their key finding: as much as an extra foot of jump distance can be gained for each pound a skier loses. For this reason, many ski jumpers maintain a dangerously low body mass index (BMI), and the sport has seen several cases of anorexia and bulimia. To counter this, the International Ski Federation has stipulated that athletes with BMIs below a certain point will be penalized by having to use shorter skis, which makes it harder to jump as far.

"Still, computer models show that this handicap does not completely negate the benefit gained by lightness," the magazine reported.

Q. At a restaurant, what's a common circumstance where nonconformity can leave you with a bad taste in your mouth? –P. Chang
A. "I'll have the chicken," your friend says. "Oh," you think, "that's what I was going to order. I guess I'll get something else."

When people dine out together, they often seem to feel under an obligation to order different things, say Roy Baumeister and Brad Bushman in Social Psychology and Human Nature. Research by R. Ariely and J. Levav found that groups ordered different foods— and different beers– more often than would be expected by chance alone.

Then a second experiment showed this didn't happen when test subjects were instructed to order in secret. In both cases, patron satisfaction fell when diners followed their impulse to order something different.

The explanation for this is not entirely clear, but it seems conformity is not always so bad: "The people who order the same item when it is their first choice end up enjoying it more, on average, than the ones who switch to a second choice just to be different."
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