Study
Chest beats as an honest signal of body size in male mountain gorillas (Gorilla beringei beringei)
Wright, Edward; Grawunder, Sven; Ndayishimiye, Eric; Galbany, Jordi; McFarlin, Shannon C.; Stoinski, Tara S.; Robbins, Martha M.
Scientific Reports, 2021
Chest beats from wild silverbacks in the Virunga massif were recorded acoustically and their peak frequency related to body size, measured independently by photogrammetry of shoulder breadth rather than estimated by eye.
- Studied in
- Gorilla beringei beringei
- Sample size
- 25 wild adult male mountain gorillas
Larger males produced chest beats with lower peak frequencies, and the relationship was strong enough that body size is recoverable from the sound. Beat rate and duration varied between individuals in ways that may also carry identity.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
The chest beat is an honest signal of body size, constrained by the physics of the resonating air sacs, and functions in competitor assessment and mate attraction.
How NatureHQ reads it
This is the useful replacement for the strength mythology, and it is a better story. The display is not bluster; it is a measurement other gorillas can take at a distance. Because frequency is set by the size of the resonating cavity, a small male cannot fake a large male's sound — the honesty is enforced by physics rather than by good faith. That is what "honest signal" means technically, and it is why the display works to settle contests without fighting, which is the thing the chest-beating gorilla of popular imagination is supposed to be doing and is not.
- One subspecies at one site; other gorillas differ in habitat acoustics and social structure.
- Correlational — body size was not manipulated, which would be neither possible nor ethical.
- Whether receivers actually use the frequency information was inferred rather than tested by playback.
Measuring a gorilla from the sound of its chest
Is the chest beat bluster, or does it carry information a rival could use?
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: Nature PortfolioPublished in a Nature Portfolio journal.
doi.org/10.1038/s41598-021-86261-8
This reference was resolved automatically against Crossref on 2026-08-11.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-11.