the snakes biting - yes they did
My husband did the snake work for this movie................there was glass between the snake and the actor. Latex had to be put over the glass so when the snake struck there was a "skin" to bite.
oh, and here's a bit of trivia.........Bet you guys don't know who the stunt double for Heather was. Well I do, it was my husband, since he supplied the snakes for the movie, they felt he would be the best. They also rented his extensive library for the film (to make the film more authentic? ha ha). So, I guess this movie was part of his 15 minutes of fame.