"THis might sound silly, but can't they train dogs to go in the caves with cameras on their heads?"
Better yet, place a fan at the cave entrance and allow my dog to break wind inside. Guaranteed surrender! lol.
Why not put cameras on wild boars,and let them loose in the tunnels? If you think a dog can be scarey,you ain't never seen a wild hog that's pissed! Add the psycholigical aspect to this that hogs add,and it's a winner.