That Famous Gorilla Chest Thump: What They're Trying To Say

The mountain gorilla's chest thumping is unusual because it is not a vocalisation but rather a form of physical communication that can be both seen and heard.

A mountain gorilla rises up and pounds its chest to signal for a mate or scare off a foe, but the drumming that resonates through the forest might also reveal details of their physique, according to a study published Thursday. Unlike the croak of a frog or the growl of a lion, the mountain gorilla's chest thumping is unusual because it is not a vocalisation but rather a form of physical communication that can be both seen and heard. This display -- mainly by the male silverbacks who pummel their chests with cupped hands -- is thought to be a way to attract females and intimidate potential rivals. But researchers wanted to find out if the drumming sound, which can carry for a kilometre through the rainforest, also conveys information about the chest beater.