We have also experienced that, for some reason, Victor, will not eat a rat that is pregnant. He may attack it and he may kill it, but he will not eat it. We do not know why. If you see the above question then you will know why. I think, except Antarctica.
Snakes have many ways to move their bodies.
That means that in order for a snake to move forward, he must push sideways against rocks and other objects around them. The pressing against objects, and the repeated tightening up and relaxing of muscles in the snakes body is what helps the snake to move. Each set of muscles in the snake, starting with the ones closest to it's head and then working down the back towards the tail, take their turn in pushing off the object that the snake is against. This helps the snake to move forward. First the snake tightens up his muscles that are attached to his ribs, then he uses other muscles, tightens them, and the first set relaxes.