 But unlike corn snakes, they're too heavy to use concertina or lateral undulation to slither up a tree. Instead, they've got something else going for them. A python's a constrictor, which means it's really got very powerful muscles between its ribs. It's a very muscular snake. And the same powers that it can employ when constricting a large prey animal to death can be employed when climbing a tree simply by putting coils around the tree.