Previously Elements brought you the latest on our understanding of chimpanzee tool use. We know, for example, that chimpanzees will use tools to access food, such as nuts, that they cannot open with their teeth alone. Now it seems they are also highly selective about what tools they use depending on the goal and availability of raw materials in their local environment. Elements caught up with primatologist Kathelijne Koops to learn about the latest culinary delights chimpanzees have on the table thanks to their utensils.
Koops has studied a particular chimpanzee population who live in the Nimba Mountains in Guinea, Africa. These chimpanzees have learnt to use stones as cleavers and anvils in order to crack open a type of fruit - the Treculia fruit - that is native to the area.
This behaviour is exclusive to only some of the groups Koops has looked at. It appears that the chimpanzees who do use the stone cleavers and anvils have learnt this behaviour because of the environment they live in. The tools and fruits are abundant, so the tool techniques have been passed down the generations.
“The problem the chimpanzees face is that, like watermelons, the treculia have a very dense outside … you couldn’t get your mouth around it and bite it. So what the chimpanzees do, is they use what I call a cleaver, to make the initial break [in the fruit].”
“For example, a swiss army knife can be used for multiple things. It can be used to unscrew a screw, or to open a bottle. But if you don’t know that there is something drinkable or edible inside the bottle, and you don’t know how to open it, you won’t end up using it even if I put it in front of you. So we see the same kind of thing with these chimpanzees.”
The significance of this research is that it shows cultural differences between chimpanzee populations based on the environments they live in. Just as in humans, chimpanzees learn to use the tools that they need to use.
The next step for Koops and her team is to get footage of the chimpanzees using the stone tools on camera. At the moment, the only evidence she has is the remains of half eaten fruit and the knuckle imprints left around the discarded tools.
Wild chimpanzee footage courtesy of Dr Kathelijne Koops and Paco Bertolani
Koops, K., McGrew, W., & Matsuzawa, T. (2009). Do chimpanzees (Pan troglodytes) use cleavers and anvils to fracture Treculia africana fruits? Preliminary data on a new form of percussive technology Primates, 51 (2), 175-178 DOI: 10.1007/s10329-009-0178-6
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