Did they discover any burn marks around the mouth area?
Years ago I wondered if the legend of a “Fire Breathing Dragon” could have been sparked by Knights or other travelers camping near a swamp at night and their fire. The fire would have created thermal updrafts, could have pulled swamp gas in and ignited the gas then flashing back to the origin of the swamp. This would have been stunning site to witness by those around the fire. And possibly made a hell of a roar.
That would be a dead giveaway.
No but one bit my sister once.