This could be used to argue that animals have a sense of the sacred:

https://www.scientificamerican.com/article/mysterious-chimpanzee-behavior-may-be-evidence-of-sacred-rituals/

Even more intriguing than this, maybe we found the first evidence of chimpanzees creating a kind of shrine that could indicate sacred trees. Indigenous West African people have stone collections at “sacred” trees and such man-made stone collections are commonly observed across the world and look eerily similar to what we have discovered here.

Spec thread, maybe?

Quote

So far we have two main theories. The behaviour could be part of a male display, where the loud bang made when a rock hits a hollow tree adds to the impressive nature of a display. 

 

Even more evidence that we aren’t so different from our close cousins. But, as The Vat is implying, coming to a conclusion is a reach.

Lots of animals perform ritualistic behaviours and have special places, without any indication of the sacred.

You have collections of stones (presumably not rocks, or they wouldn't be thrown), at specified places near large trees. They might be ammunition caches at strategic locations, in case of territorial conflict. The banging of a stone against a tree may mean "no enemy sighted". If the same thing happens in many places, among different troupes of apes, there is good reason to doubt a religious component: How would a belief system have spread? Was a chimp named Saul recently released from human captivity?