http://www.americaswetlandresources.com/wildlife_ecology/plants_animals_ecology/animals/reptiles/alligator.htmlOlfaction (smell): Alligators have two sets of oily musk glands. One set is at the rear of the lower jaws (used when bellowing), and the other is in the cloaca (used when head slapping). It appears that musk is used mostly on the surface of the water, and less so in the air. The following eight elements of communication bellowing and/or head slapping) are quite variable, but predictable. Their function may be the following:
attract others to the courtship grounds
aggressive signal to all others of the same sex
give information on size, sex, and dominance of the bellower
synchronize group activities
define territories early in the season (there is evidence of fighting among males at this
time).