National Geographic : 2010 Mar
PHOTO: JOEL SARTORE WITH CHARLES RASH W ILDLIFE Slithering Secrets No legs? No problem. Snakes get around just fine on land, thank you---only not quite the way we'd thought. David Hu, a mechanical engineer at Georgia Tech, says belly scales and body lifting are the keys to serpent locomotion. Scientists knew snakes use their sides to push off twigs and rocks but were baffled by how they could slither so well on smooth surfaces. Hu investigated their movements and found the answer in their stomach scales, which overlap like "a spread deck of cards." These scales catch on ground features such as cracks and crevices, even tiny ones, and increase friction, which snakes use to propel themselves forward. To go faster, they shift their weight by slightly raising parts of their body, as we do. "We don't drag our legs when we run or walk," says Hu. His findings may soon lead to better "snake-bots" for post- disaster search-and-rescue missions and medical proce- dures like colonoscopies. For now, they're simply further proof that snakes can travel in efficient style. ---Jeremy Berlin In this double exposure, a Texas coral snake struggles to move on featureless black velvet, where belly scales can't act as "friction hooks."