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