How To Be A Snake [Life in Motion]

If you stroke a snake, its skin feels slick and slippery (ed: or smooth, at any rate). Yet according to a new study by scientists at New York University and Georgia Tech, snakes actually depend on friction to move. Snakes crawl by contracting the muscles that run along their body and pushing against the ground. Recently David Hu and his colleagues took a close look at that snake-surface interface. They anesthetized snakes and lay them on a board. By tipping one end of the board, they could see how well a snake’s body could hold onto the surface thanks to friction alone, without any extra forces generated by the snake’s muscles. Hu and his colleagues discovered that snake scales can actually create a lot of friction by catching on tiny bumps on the surface they’re lying on. (They only feel smooth if you stroke them tailward.) The scientists found that the scales can generate twice as much friction if a snake is sliding forwards than if it is sliding sideways.