Gorillas beat their chests primarily as a form of communication and display of strength. The main reasons include asserting dominance and authority, warning or intimidating rivals, attracting females, and communicating location or presence, especially in dense forests. It is also used to resolve conflicts without physical aggression and is sometimes a sign of excitement or play in younger gorillas. The chest-beating sound is produced by hitting the chest with cupped hands, amplified by the gorilla’s large chest cavity, signaling the gorilla's physical strength. This behavior helps to maintain social hierarchy and group cohesion, especially for dominant silverback males. Chest beating can also precede a bluff charge intended to warn rather than attack.
In summary, chest beating is a powerful multi-functional behavior for gorillas, serving dominance display, communication, threat warning, mating attraction, and social conflict resolution purposes.
