But they do not gather where they started. No, they gather in a different place. Certain trails, you see, are already written into the landscape through the passage of animal bodies. Animal trails are a proto-medium, a physical record of intents, and needs, and resources. Even an ant knows that following a trail will lead you to something good and useful.
Some animals can track each other through scent, but chimpanzees have a bad sense of smell.
They bend and break branches, they tear off big leaves and place them carefully on the ground, to point the way they have gone. The apes that follow read these symbols, and they follow them. So, these apes leave symbolic messages by deliberately changing the vegetation. Unfortunately for them, they're not very good at it. Bonobo chimpanzees have never gotten beyond the left bank of the Congo River.