Why do Gorillas Beat Their Chests?

What Chest Beats Communicate?

The researchers collected a total of 36 chest beat sound recordings from six different male gorillas. They specifically focused on aggressive displays involving chest beats directed at members of the same species. This data was then utilized to determine a chest beat rate for each male gorilla.

“We were able to demonstrate that mountain gorilla chest beats effectively communicate information about the body size of the chest beater. This suggests that the chest beat serves as an honest indicator of body size,” Wright explains.

In previous studies, his team established that larger males tend to be more dominant than smaller males in groups with numerous males. They also found a correlation between body size and reproductive success.

“Being large is a crucial factor for male gorillas,” Wright emphasizes.

Silverback mountain gorillas

In this recent research, the team uncovered that body size is reliably communicated to other gorillas through chest beats. Larger male gorillas produced chest beats with lower peak frequencies compared to smaller male gorillas.

“This is significant because we believe that rival males are likely to utilize this information to assess the size of the gorilla emitting the chest beats.

This will assist them in determining whether to engage, escalate, or withdraw from conflicts. It’s not advisable to challenge a larger male, as the outcome is likely to be unfavorable,” he states.

“The potential for injury, and even fatality, is substantial in these large and powerful animals,” Wright further explains. “We propose that chest beats play a crucial role in these conflicts, leading to the resolution of most disputes without resorting to physical combat. Conversely, females are expected to consider the body size information conveyed through chest beats when selecting mates.”