The ritual has similarities with the building of shrines or cairns, a human ritual that has been happening for thousands of years and across civilisations
New footage shows chimpanzees engaging in bizarre behaviour — which might be a form of sacred ritual that could show the beginnings of a kind of religious belief.
Chimpanzees in West Africa have been spotted banging and throwing rocks against trees and throwing them into gaps inside, leading to piles of rocks. Those rocks do not appear to be for any functional purpose — and might be an example of an early version of ritual behaviour.
The discovery might help researchers learn more about the basis of human religion and rituals, and how such activities formed in our own history.
The scientist described seeing the behaviour through cameras that were set up to watch the chimpanzees. They saw them assembling piles of stones — of a similar kind of the ritual cairns that have been found throughout human history.
Chimpanzees and other apes have long been known to use stones and other materials as tools, including their use as nutcrackers to get into food that is cased in a hard shell. But the new behaviour doesn’t seem to have the same functional purpose.
“This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees,” the researchers write in their abstract.
“The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites.”
For humans, stone buildings and piles have symbolised a wide variety of things, which have seen them used in burials and shrines. Those examples are often among the earliest examples of religious behaviour in human history, and so the chimpanzee behaviour could represent a similar instinct.
The chimpanzee behaviour could also represent a direct connection with human religious rituals. Indigenous West African people also collect stones at sacred trees — and similar behaviour is seen elsewhere — in a way that looks “eerily similar to what we have discovered here”, one of the researchers wrote.
In a piece written around the findings, researcher Laura Kehoe described the experience of watching the chimp look around and then fling a rock at the tree trunk.
“Nothing like this had been seen before and it gave me goose bumps,” she wrote.
The discovery could offer insights into the way that humanity’s sacred rituals began, she wrote.
“Marking pathways and territories with signposts such as piles of rocks is an important step in human history,” wrote Ms Kehoe. “Figuring out where chimps' territories are in relation to rock throwing sites could give us insights into whether this is the case here.”
