A research team has found that chimpanzees possess an advanced understanding of the physical and geometric properties of materials used in their daily lives, and can select suitable materials for making rudimentary tools.
A joint research team from the universities of Oxford in the UK, Leipzig in Germany, Algarve and Porto in Portugal, the Max Planck Institute for Ecology and Ecology, and the Jane Goodall Institute of Ecology and Ecology in Tanzania has confirmed that chimpanzees living in Gombe Stream National Park in Tanzania apply a form of engineering to the simple tools they use in their daily lives. They select the plants from which these tools are made based on their physical properties and suitability for the intended purpose.
Researchers believe these findings, published in the scientific journal iScience, shed light on the artistic and craftsmanship skills of apes, which enable them to manufacture perishable tools—a field largely unexplored in human evolutionary research. Termites are a nutritionally rich food source for apes, providing them with energy, vitamins, minerals, and protein.
The research team found that chimpanzees construct a type of thin probe to extract ants from their nests. Since nests consist of narrow, winding tunnels and passages, it became clear that chimpanzees use flexible, soft, and non-rigid twigs to make tools that they can easily insert and remove from the nests and extract the ants inside.
Study team leader Alejandra Pascual Garrido used a portable material hardness measuring device to test the nature of the plants used by chimpanzees to make these probes, while also examining other plant species found in the environment that the chimpanzees do not use for this purpose. The experiment revealed that the plants not used by the chimpanzees were 175% harder than their preferred materials, making them easily broken when used to penetrate ant nests.
In statements to the scientific research website "Science Daily", Alejandra Pascual Garrido, who has been studying the materials used by chimpanzees in Gombe National Park for more than a decade, says that this experiment represents the first "comprehensive evidence that chimpanzees select tool materials based on specific mechanical properties." It also turns out that chimpanzee groups living 5,000 kilometers away from Gombe National Park also use similar plants, such as graphia or thorn, to make the primitive tools they use in their daily lives. This indicates that the selection of suitable materials for tool making may be instinctive for the apes and not part of learned habits. Pascual Garrido believes that chimpanzees have natural engineering skills that go beyond simply choosing a stick or tree branch to perform a particular task. They also have the ability to select the appropriate material to make the tools they use more effective.
"This new approach, which combines biomechanics and ethology, can help us understand the cognitive and mental processes behind toolmaking in monkeys, how they select and evaluate materials in their environment, and their suitability for making the primitive tools they require," says Pascual Garrido, of the University of Oxford's School of Humanities and Social Sciences. She believes these findings raise important questions about whether these skills or expertise can be acquired—that is, are monkeys passed down through generations by watching their mothers make tools from certain materials, thus learning the same skill from observation. They also ask whether monkeys use the same expertise to make tools suitable for other food-producing tasks, such as collecting honey from beehives.
"These findings have important implications for understanding how humans evolved to acquire the ability to manufacture the tools we use in our daily lives," says Adam van Kasteren, a researcher at the Department of Human Origins at the Max Planck Institute for Research in Biology and Biomechanics and Evolutionary Biology.
He added: "While perishable materials such as wood are rarely observed in the anthropological record, the mechanical principles behind selecting materials suitable for tool making remain constants across all species across time."
He noted that studying how chimpanzees select materials based on their structural and mechanical properties can help us understand the physical constraints and requirements that governed early human tool-making behavior. He noted that using comparisons opens the door to new discoveries to understand the foundations of primitive technology that are not found in the records of anthropology.