Engineering skills in plant material selection and tool manufacture by chimpanzees

In primate behavioral research, the tool use of chimpanzees (Pan troglodytes) has often been compared with the technological abilities and cognitive foundations of early human ancestors. For decades, anthropologists have relied largely on archaeological stone tools to infer the evolution of early human technology. Yet many tools used by early hominins were likely made from wood or other plant materials that decay easily and rarely survive in the archaeological record. As a result, our understanding of these perishable technologies remains limited. Observing how living chimpanzees manufacture and use tools made from plant materials therefore offers a valuable window into the origins of human technology.

Chimpanzees employ tools in a wide variety of contexts. Tools can be used for cleaning, grooming, obtaining water, and especially for feeding behaviors that require more complex techniques. One of the most technologically sophisticated examples is termite fishing. When chimpanzees encounter a large termite mound, they select suitable plant stems or fibers and fashion them into slender, flexible probes. These probes are inserted into termite tunnels, provoking soldier termites to bite onto the tool with their mandibles. When the chimpanzee withdraws the probe, the attached termites can be easily collected and eaten. This seemingly simple action actually involves several coordinated steps: selecting appropriate raw materials, modifying the material into a usable tool, skillfully manipulating the tool during use, and improving performance through repeated trial and learning.

(B) Schematic illustration of a rigid termite fishing probe or (C) a flexible termite fishing probe（Image source：Pascual-Garrido A et al. (2025)， CC BY 4.0 ）

At Gombe Stream National Park in Tanzania, researchers analyzed the plant materials used by chimpanzees to determine whether the animals consciously select raw materials based on physical and mechanical properties. Their findings indicate that the plants chosen by chimpanzees are not merely those that are most readily available. Instead, the selected species tend to produce probes that are more flexible and have lower bending stiffness. Such flexibility allows the probe to navigate the complex and twisting tunnels inside termite mounds without becoming stuck or breaking. Even within the same plant species, different individuals can vary in their physical properties, yet chimpanzees are still able to choose stems or fibers with particularly suitable characteristics. This pattern suggests that chimpanzees possess at least a partial understanding of the functional relationship between a tool's material properties and its performance.

(A) Termite fishing probes; (B) holes produced by chimpanzee termite fishing probes; (C) a termite fishing probe inserted into a termite mound（Image source：Pascual-Garrido A et al. (2025)， CC BY 4.0 ）

The ability to select suitable materials may arise from two complementary sources. One is individual experience gained through repeated experimentation. The other involves social learning, particularly from mothers and other group members. Observations show that young chimpanzees frequently remain close to their mothers when learning termite fishing techniques. Juveniles often reuse tools left behind by their mothers and gradually become familiar with both the manufacture and use of probes. Such maternal transmission influences details such as the preferred length and thickness of tools, and it also reflects cultural variation between chimpanzee communities. Even neighboring groups may differ in their preferred tool dimensions or plant materials. Because these differences cannot be fully explained by environmental factors alone, they are widely interpreted as evidence of cultural transmission.

A chimpanzee using a termite fishing probe（Image source：Pascual-Garrido A et al. (2025)， CC BY 4.0 ）

These behavioral patterns have important implications for understanding the evolution of human technology. Archaeological evidence shows that early humans selected raw materials for stone tools according to their mechanical properties. The behaviors observed in chimpanzees provide a parallel model for this evolutionary logic. They demonstrate that nonhuman primates are capable of making subtle judgments about the engineering properties of materials used in tools. If such abilities were already present in the common ancestor shared by humans and chimpanzees, then the roots of human technological culture may be considerably older and more diverse than what can be inferred solely from stone artifacts. In this sense, chimpanzees represent a living window into a deep technological past.

The Jane Goodall Institute also contributed to this research.

Dr. Dame Jane Goodall passed away in Los Angeles, California, on October 1, 2025.

We express our gratitude to Dr. Jane Goodall for her extraordinary contributions to primate research.

Author: Shui-Ye You

Reference:

Pascual-Garrido A et al. (2025). Engineering skills in the manufacture of tools by wild chimpanzees. iScience.