re: Would you stand on this rock?

Some Taiwanese grad students came along on a geology field trip I was leading. We stopped at a river and a snake swam by. They asked me if it was poisonous. I said I didn't know and I didn't want to find out.
One smiled at me and said, "If not poison, not good to eat, if poison good to eat."

I don't know if they ever got to test that with Tennessee snakes.