As for venom in colubrids, I remember reading somewhere, though I can't remember where, that there have been occasional cases of children getting bit while feeding their snakes that resulted in swelling of the hand and arm and the kids feeling ill--all of which points to some sort of substance being secreted by the snake, whether it be venom or just something that causes some sort of an allergic reaction. I've never seen any study that proved the venom theory or analyzed the substance, though
