Ciro Rubino, age 10, of Sarasota, Florida, for his question:

How does a sidewinder travel?

No snake can make his way across a polished floor or smooth glass. He has rows of hard spikes on his underside and he must use them to grip small bumps on the ground. Snakes travel best through spikey grass, over gritty gravel and rough ground. These surfaces proms ' vide bumps for them to shove against as they push forward. Most snakes cannot travel through sand because it is too soft and the grains are too small to be gripped. But the sidewinder lives in the desert and long ago he learned a snakey trick of his own for traveling over the sand.

He coils his graceful body in an S shape    and as he goes forward, his body follows along in an S shaped pattern. The two loops are held above the sand and only three parts of his body touch the ground. He moves his head forward and puts it down. Then the first loop sloops up a notch and then the second loop, with the tail dragging behind. He winds his way forward by swinging his loops    and the sidewinder's loops curve to one side of his head.