They recorded the duration, number and frequency of 36 chest beats made by six of the males and linked them to measurements taken from photos of their shoulder width.
The researchers from Germany, Spain and the US believe that the bigger males have larger air sacs near their larynx, making the drumming beat sound lower in pitch to the human ear.
Gorillas are highly competitive in the search for a mate, with a single male living among a group of females.
Different gorillas drummed more rapidly and for longer, which could allow them to be identified by sound through the dense tropical forest, according to the paper
Big beats: Gorilla chest thumps signal body size
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Gorillas do not bluff when they chest beat: honest signalling indicates body size
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Gorillas do not bluff when they chest beat
The gorilla chest beat is one of the most emblematic sounds in the animal kingdom, even working its way into our informal speech signifying overblown advertisement of one’s own achievements. However, until recently it was unclear what information gorillas were conveying when they gave these impressive displays. A team of international researchers show that chest beats reliably indicate the body size of the chest beater. Body size indicates competitive ability in gorillas. Therefore this information is likely to be crucial for rival males as well as females in influencing mate choice.