They use their "abs"...Truly impressive, I agree. They use their scutes in much the same way ice skaters push off the edges of their blades...& they actually have
trouble moving if you put them on a smooth glass coffee table, for example, because there's nothing to push off against. That's why some snakes learn to side-wind
in soft sand, by basically throwing a loop of their body forward & then repeating on the other side. The more you learn about snakes, the more amazing they are.
BTW, her yellow face and especially her orange eyes really suggest she has some Everglades rat snake genes.