Chimpanzees in three West African countries—Guinea Bissau, Côte d’Ivoire (the Ivory Coast), and Liberia, have been observed taking part in strange behavior. They store a great number of rocks in the hollows of trees. Then, usually a male, takes one of the rocks, walks a distance away, grunts an utterance, and hurls the rock at the tree, leaving a mark on it. The rock is then placed back in the hollow to be reused in this manner again.
No chimps east of these countries have been observed doing this. What’s more, there seems to be no reason for it tied to survival. It has nothing to do with acquiring food, mating, or furthering one’s status. Researchers say it might be a unique display of male power, marking the border of their troop’s territory, or even a spiritual ritual.
A team of 80 international scientists, led by Hjalmar S. Kuhl and Ammie K. Kalan, conducted the study. Kuhl and Kalan hail from the Max Planck Institute in Germany. The team set up camera traps in four remote locations in West Africa, where they caught footage of chimps taking part in this unusual and so far, unexplained behavior. Their findings were published in Scientific Reports, part of the journal Nature.
Source: News Now/Big Think Online