They beat their breasts so they don’t have to beat your ass.
The image of King Kong hitting his chest might seem like the ultimate threat sign. However, German scientists have found that gorillas hit their sternums to avoid, rather than instigate, a fight.
Specifically, the ad attacks herald the size of the primate, its fighting skills, and other practical information, providing rivals with an image of what they would face if they decided to go ahead, National Geographic reported.
“We found it to be definitely a real, reliable signal: men transmit their true size,” Edward Wright, a researcher at the Max Planck Institute for Evolutionary Anthropology, told The Guardian. He co-authored the percussion study published Thursday in Scientific Reports.
Many have speculated that gorillas communicate their size through moob-banging, but “there was no data to support this claim,” according to Roberta Salmi, director of the Primate Behavioral Ecology Lab at the University of Georgia.
To prove his disturbing theory, Wright and his team spent 3,000 hours studying endangered mountain gorillas in Rwanda’s Volcanoes National Park, National Geographic reported.
They used audio equipment to record the chest rhythm sound frequencies, the number and duration of each screen in six animals between November 2015 and July 2016. They then compared these variables with the size of the specimens, which were they measured by analyzing photos of the beasts.
The researchers found that larger gorillas produced lower frequencies than their smaller counterparts, meaning that pectoral percussion was an “honest signal of competitive ability” and size, rather than showing an exaggerated threat, according to the study. Think of a UFC fighter listing his stats against a drunk who blows his chest at the bar.
“They’re big, powerful animals that can do a lot of harm.”
Because larger body size correlated with a higher social rank (and therefore with the ability to fight), the scientists deduced that transmitting it through a chest beat could help gorillas avoid violence, which is essential in a species that grows up to 500 kilos.
“Even if you’re likely to win a fight, there’s still a pretty high risk factor,” Wright explained. “They’re big, powerful animals that can do a lot of harm.”
“Very often it’s about beating the chest and then not fighting,” he said, adding that the most poignant gorillas could be deterred by a larger silver background, the low rate of which is likely caused by larger laryngeal sacs. For the same reason, an alpha Mighty Joe Young can listen to the drum of a single beta monkey and decide that they are too small to use.
Along with the size of rivals, breaststrokes could also be used to attract mates, according to research.
The next step is to find out how other gorillas translate the language of murder.
“It will be very interesting to see how hearing your heartbeat in your surroundings can affect your movements and making decisions about which areas of your home area to use,” Salmi said.