One of the most common ways snakes climb trees is by employing a technique called “concertina locomotion”. As you can see in the film they hold and release their body in an S-shaped pattern to progress upward, similar to how a person climbs a rope. As for the huffing and puffing that was going on. Pythons can do this as a way to sound more intimidating. It’s also common with larger pythons when climbing as it’s compressing the air out of their lungs as they squeeze around the tree. I think there

10 of the Largest Venomous Snakes in the World - Wildlife Informer