Im pretty sure no one will get this, so I'll explain. In most movies/tv shows, gorilla chest beating in movies sound like earthquakes. In real life, however, it sounds like suction cups. :
Gorilla chest beating sounds different based on size
why do gorillas beat their chest - Silverback Gorillas Pamoja Safaris
Gorillas don't bluff when they chest beat: honest signaling indicates body size - Dian Fossey