Mexico City /
A very representative gesture of the gorillas that has been portrayed countless times in documentaries, movies and so on is when they beat his chest. Contrary to what one might think, it is not a battle cry. Have you ever wondered why they do it? Then we tell you.
These animals that beat their chests quickly with their drum-like hands can thus transmit information about their body size and allow the identification of individuals. This is suggested by a study published in the journal Scientific reports.
Results of the investigation
The result shows that non-vocal behaviors can contribute to mountain gorilla communication. Although it had previously been suggested that gorillas could beat your chest to transmit information, the exact nature of that information was unclear.
Researcher Edward Wright of the Max Planck Institute for Evolutionary Anthropology in Germany observed and recorded 25 adult and wild silverback gorillas, monitored by the Dian Fossey Gorilla Fund in the Volcanoes National Park, Rwanda.
According to a statement from said institute, body size was determined from photographs by measuring the distance between the shoulder blades of the gorillas. Using sound recordings, the authors measured the duration, number, and audio frequencies of 36 chest strokes performed by six of the males.
The authors found that the audio frequencies of the chest strokes performed by the larger males were significantly lower than those of the smaller males. Larger males may have larger air sacs near the larynx, resulting in it could reduce the frequencies of the sound produced when hitting the chest.
They were also observed variations in the duration and number of chest strokes of different gorillas. These variations are not related to body size, but can allow identifying individuals who hit themselves.
The authors suggest that the sound of these blows can allow mountain gorillas to communicate through the dense tropical forests in which they live, where it is often difficult for them to see each other. They speculate that mountain gorillas may use the information transmitted through breast strokes to choose a partner and evaluate the fighting ability of competitors.