This chimpanzee population has a hobby of throwing rocks at trees and the mysterious reason behind it

Biologists have recently discovered some unusual behavior in chimpanzees living in the forests of West Africa. In particular, adult males often have a 'hobby' of picking up rocks thrown at the trunk then screaming, then fleeing. We all know chimpanzees are very intelligent primate species, they possess relatively logical thinking and of course never waste time on meaningless things. So what is the reason behind the strange hobby of this West African chimpanzee population?

A group of researchers from the Max Planck Institute for Anthropology of Evolution in Leipzig, Germany, first discovered the behavior three years ago. Because only chimpanzees living in West Africa have a hobby of throwing rocks at trees and screaming, scientists believe this behavior is localized, potentially part of any 'ritual'. that between chimpanzees, but it is unclear what purpose it is.

To investigate the underlying cause, the team planned to conduct many in-depth experiments to determine why the chimpanzees were interested in this seemingly both exhausting and futile activity. They set up a camera system and recording mic in a West African forest, an area where many chimpanzees live in groups, then wait for the chimpanzees to perform their 'ritual'.

The researchers analyzed all the audio / video recordings and found that chimpanzees tended to throw rocks at the stalks producing deeper and longer (echoing) sounds. Often these are ancient trees, with exposed roots. 

Going deeper into the analysis, the researchers found that "low-frequency sound travels farther in the environment as well as better suited for long-distance communication," and that more resonant sound will exist. longer in the environment. It is therefore conceivable that this is a special mode of communication that only West African chimpanzee populations have.

In addition, chimpanzees will only throw rocks at a tree they are familiar with, never choose a new tree, and scientists think this factor may be related to territorial behavior. Maybe the location of the trees is related to nearby resources like food and water. Creating a deep, echoing sound when throwing rocks at a tree can be a signal for other individuals to know their presence as well as express their current emotions.

But all of this is just a hypothesis, scientists still need to do more in-depth studies to reach a final conclusion.