Ever hear an alligator bellow? If these rumbles sound to you like something that would come out of a dinosaur, it's probably because the alligator hasn't changed all that much since the days when the T-Rex was out running around. Today's gators might have decreased a good deal in size, but their body structure and instincts are very much the same as their prehistoric ancestors.
Gators bellow as part of their courtship ritual and as a territorial display. What's really cool about all of this racket is what you don't hear – alligators produce a low-frequency sound that's inaudible to humans.
Neat stuff, huh?