In 2008, the snook201 YouTube Channel uploaded a video showing an alligator and it's "territorial bellows."
"This is some video taken in "everglades national park on the Anhinga trail during the dry season. Many alligators are in this area due to low water levels. The bellowing and raising out of the water is a territorial and mating display done by the male alligator."
Thumbnail Photo Credit: snook201 YouTube Channel