Why do chimps throw stones at trees?

One group of chimps repeatedly throws stones at specific trees, in what may be a cultural behaviour with mysterious purpose

One group of chimps repeatedly throws stones at specifc trees, in what may be a cultural behaviour

Chimpanzee prepares to throw rock at tree (MPI-EVA PanAf/Chimbo Foundation)
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Scientists have known for some time now that chimpanzees are capable of using tools for the purpose of food gathering. They use sticks to collect termites, and rocks to crack nuts. But a new study by an international team of scientists, including Dr. AmmieKalan, a Canadian Post-doctoral researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, has found evidence of chimps using a tool for a more puzzling purpose.

Chimps in the West African country of Guinea have been observed hurling rocks at trees. Although the researchers are still mystified as to the exact purpose of this behaviour, they believe it may be a form of communication. The sound of a rock hitting a hollow tree may be a signal of their location to other chimps, or possibly a claim on a territory.

The chimps repeat this activity, using the same stones and the same trees. It is believed to be a cultural behaviour specific to this group of chimps.

Related Links

Paper in Nature Scientific Reports
- Max Planck Institute For Evolutionary Anthropology release
- Blog by Dr. Kalan's co-author on The Conversation web site
Discovery Newsstory