They hit your chest so they don’t have to hit your ass.
The image of King Kong hitting his chest may seem like the ultimate threat display. However, German scientists have found that gorillas hit their sternum to prevent – rather than instigate – a fight.
Specifically, pec-pounding announces the primate’s size, fighting ability and other practical information, providing rivals with an image of what they would face if they decided to take down, National Geographic reported.
“We found that it is definitely a real and reliable signal – males are transmitting their true size,” said Edward Wright, a researcher at the Max Planck Institute for Evolutionary Anthropology, to the Guardian. He is co-author of the percussive study published Thursday in “Scientific Reports”.
Many speculated that gorillas communicate size through moob taps, but “there was no data to support that claim,” according to Roberta Salmi, director of the Primate Behavioral Ecology Laboratory at the University of Georgia.
To prove his stimulating theory, Wright and his team spent 3,000 hours studying endangered mountain gorillas in Rwanda’s Volcano National Park, National Geographic reported.
They used audio equipment to record beating sound frequencies, number and duration of each display in six animals between November 2015 and July 2016. Then, they compared these variables to the size of the specimens, which were measured through the analysis of photos of the animals.
The researchers found that larger gorillas produced lower frequencies than their smaller counterparts, meaning that chest percussion was an “honest sign of competitive skill” and size, rather than an exaggerated threat display, according to the study. Think of a UFC fighter listing his stats against a drunk puffing out his chest at the bar.
As the size of the larger body correlated with a higher social position – and therefore fighting ability – scientists deduced that transmitting it through chest beats could help gorillas to avoid violence – a necessity in one species. that grows up to 500 pounds.
“Even if you are likely to win a fight, there is still a very high risk factor,” explained Wright. “They are big and powerful animals that can cause a lot of damage.”
“It’s often all about hitting the chest and then they don’t fight,” he said, adding that thinner gorillas can be deterred by a larger silverback, whose bottom beat is probably caused by their larger laryngeal sacs. Likewise, an alpha Mighty Joe Young can hear the drum solo of a beta monkey and decide that they are too small to play.
In addition to assessing rivals, chest beating can also be used to attract partners, according to the survey.
The next step is to find out how other gorillas translate the language of aggression in the chest.
“It will be very interesting to see how listening to your chest beats in your surroundings can affect your movements and decision making about which areas of your home to use,” said Salmi.