Research press release


Scientific Reports

Zoology: Mountain gorillas may use chest beats to communicate information about themselves

マウンテンゴリラ(Gorilla beringei beringei)の胸たたき(手で胸を素早くたたいて太鼓のような音を出す行動)は、自身の体サイズに関する情報を伝える行動であり、個体の特定を可能にする可能性があるという見解を示した論文が、Scientific Reports に掲載される。この知見は、マウンテンゴリラのコミュニケーションに非発声行動がどのように寄与するのかを示している。

ゴリラ類が胸たたきをして情報を伝えていることはすでに提唱されているが、伝えようとする情報の正確な内容は分かっていない。今回、Edward Wrightたちの研究チームは、ルワンダのボルケーノ国立公園でダイアン・フォッシー・ゴリラ基金によって監視されている野生のシルバーバックゴリラの雄の成体25頭を2014年1月から2016年7月まで観察し、記録を取った。体サイズは、写真に写ったゴリラの左右の肩甲骨の間隔を測定して決定された。また、Wrightたちは、録音を用いて、6頭の雄による36回の胸たたきの持続時間、回数、可聴周波数を測定した。



Chest beating by mountain gorillas – rapidly beating their chests with their hands to produce a drumming sound – may convey information about their body size and allow identification of individuals, a study published in Scientific Reports suggests. These findings demonstrate how non-vocal behaviours may contribute to mountain gorilla communication.

Although it had previously been suggested that gorillas may beat their chests to convey information, the exact nature of that information was unclear. Edward Wright and colleagues observed and recorded 25 wild, adult male silverback gorillas monitored by the Dian Fossey Gorilla Fund in Volcanoes National Park, Rwanda, between January 2014 and July 2016. Body size was determined from photographs by measuring the distance between the gorillas’ shoulder blades. Using sound recordings, the authors measured the duration, number and audio frequencies of 36 chest beats made by six of the males.

The authors found that the audio frequencies of chest beats made by larger males were significantly lower than those made by smaller males. Larger males may have larger air sacs near their larynx, which could lower the frequencies of sound they produce while chest beating, according to the authors. Variations were also observed in the duration and number of chest beats made by different gorillas. These were unrelated to body size but may allow chest-beating individuals to be identified.

The authors suggest that the sound of chest beating may allow mountain gorillas to communicate across the dense, tropical forests in which they live, where it is often difficult for them to see one another. They speculate that mountain gorillas may use the information conveyed through chest beats to inform mate choice and to assess the fighting ability of competitors.

doi: 10.1038/s41598-021-86261-8


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