Scientists have captured chimpanzees performing a bizarre ritual

Scientists have observed the interesting way in which chimpanzees interact with each other and use tools for quite some time. Recently, they discovered chimpanzees in West Africa exhibiting a usual behavior that they haven’t seen anywhere else: The chimps are collecting rocks in trees. For what reason, however, the researchers still don’t know.

Scientists Have Observed West African Chimpanzees Collecting Rocks

Scientists have been watching West African Chimpanzees exhibit rather strange behavior. They are collecting a large number of rocks and store them in hollowed-out trees. A male chimp then takes a rock out, walks some paces away, grunts, throws the rock at the tree to “mark” the tree, then puts it back. The chimp will then return later to do this little ritual again. They don’t yet know why they do this, and it is only chimps in the West African countries of Guinea Bissau, The Ivory Coast, and Liberia who they’ve witnessed doing this. (1)

Why Are They Doing This?

Well, the scientists don’t know why the chimpanzees are performing this strange rock ritual, they have figured out a few reasons why they are not doing it. It does not appear to be a survival tactic. The ritual has nothing to doing with gathering food, protection, improving status, or mating. One thing they have noticed, however, is that it is only the males who seem to be participating.

This has led them to believe the ritual could be one of these reasons: A display of power, marking the border of their group of chimpanzees’ territory, or perhaps some sort of spiritual ritual. These are all theories, however. None of them have actually been confirmed. The researchers wrote this:

“We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites.”

Chimpanzees Are Known To Use Tools In Their Daily Life

In addition to using rocks as tools, chimps use other tools as well. They use sticks as fishing poles to catch termites and ants, and they also use sticks to dig for honey and to scratch themselves. Chimps are also known to use leaves as sponges for drinking water, as gloves for handling hot objects, and even as umbrellas. (2)

Tools As Weapons

Chimps are also known to use tools as weapons. They will sharpen sticks into spears and throw them at predators, such as leopards, to ward off the attack. Chimps have been seen using rocks or branches in a similar fashion against humans who threaten them or their families.

Tools As Social Catalysts

Chimpanzees have also been seen using tools for social functions. For example, they will throw sticks at each other as a form of play or to establish dominance. They also use leaves as napkins when eating, which is likely a way for them to show their friends that they have food and invite them to join in on the meal.

The Bottom Line

Chimpanzees use tools in a variety of different ways in their everyday lives. Until now, these tools have been used for general survival, food, and mating. This new rock-storing and throwing behavior have definitely piqued the curiosity of many scientists who regularly study chimpanzees. While they still don’t know exactly why they are doing this, it will be fun to continue to observe the behavior and figure it out.


  1. Scientists have captured chimpanzees performing a bizarre ritual.” Big Think. Philip Perry. July 23, 2017.
  2. EVA