Actually, bearded dragons have scent receptors in their mouths. Their tongues are made to analyze their surroundings to help track down potential mates or food. Scientists are still exploring this but it is believed that whereas their nostrils smell things and tell where they are by moving around and the scent becomes stronger or weaker, the tongue provides stereo smell, letting them know the direction of something without moving towards or away from it. Very cool creatures, huh?
Perhaps we should try covering our beardies eyes and nostrils, surrounding them with worms, and see what happens? LOL