Raiders Of The Lost Ark

How did Spielberg film about the snake pit scene in Raiders of the Lost Ark? Do they actually walk through the snake (above them), or are they some kind of path for actors and stunt double work, and they did not step in- over them? In addition, these snakes have been made, or were they non-venomous? I know they are actually live snakes, but wondered how they shot the scene without being bitten people and how they came by snakes without breaking them.

Here's a video shoot this scene ...

http://www.youtube.com/watch?v=-P4S0S0R7 ...

Most likely generated by computer.

They were not poisonous snakes that players come and there was glass between Indy when he lands on the ground and was staring at one. The crew made a path for use torches so that the snake would not be too close and if 1, they had a Wrangler on the board with the snake to move.