As I was thinking about how fun it would be to have a job where you solve puzzles in the world, it struct me that media never depicts archeology in a real light. My short search seemed to confirm my thoughts. Most ancient sites are not guarded by elaborate traps or secret riddles to get in. From what I’ve found there were some crossbows here and there. Some rare hidden rooms with a lot treasure, but again, no traps.
If you’re serious about your big pit trap you need to be buying your snakes directly from suppliers. Trap-o-mart charges at least 50% more for the same snakes and the benefits of building a relationship with your supplier are too great to ignore.