
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: SUNDAY, April 14, 1991                   TAG: 9104160458
SECTION: EDITORIAL                    PAGE: B-2   EDITION: METRO 
SOURCE: 
DATELINE:                                 LENGTH: Medium

CATERPILLAR/ LESS EFFICIENT THAN PEOPLE

FROM AN engineering standpoint, we humans don't always stack up well against the so-called lower orders of creatures. Flap our arms as we may, we can't fly like the bird. The sea turtle outlives us by 50 years or so. The shark reached its present evolutionary stage long before man began standing upright. The ant can carry several times its body weight. The flea is a better lover. And so on.

It comes as some comfort, then, to learn that the caterpillar is rather an ill-designed creature, at least for getting around. Years ago, its name was applied to a tractor because of its deliberate movement and ground-hugging wheelbase. But the main reason the caterpillar is slow is that it's inefficient.

Scientists determined this by, wouldn't you know, building tiny treadmills and compelling caterpillars to move on them. (Whether they were also given heart-rate and stress tests has not been revealed.) The Rutgers University report says, in the best academic style, that "caterpillar organization precludes the possibility of high-speed locomotion." An important discovery.

"Organization" means how the animal is put together. Unlike ours, its skeleton is not solid but filled with fluid. It moves by rhythmic contractions of muscles that compress its soft segments in sequence, from back to front - squeezing its body forward. This forces the creature to burn 4.5 times as much energy to move a weight a given distance as do animals with solid skeletons.

So, thanks to Nature, we humans can move farther and faster on comparatively less fuel than this little leaf-chewer. We also can use its hydraulic principles in our machines. We even put some species of caterpillar to work for us. On the other hand, we can't make silk ourselves. Back to the evolutionary drawing board.

by CNB