Chimpanzees in Tanzania's Gombe Stream National Park demonstrated engineering skills by carefully selecting specific plants to craft flexible tools for termite fishing, according to new research published in the journal iScience. A multidisciplinary team of researchers from the University of Oxford, the Max Planck Institute for Evolutionary Anthropology, the Jane Goodall Institute in Tanzania, the University of Algarve, the University of Porto in Portugal, and the University of Leipzig discovered that these primates employ a degree of engineering when making their tools for termite extraction, reported Science Daily.
Termites are a good source of energy, fat, vitamins, minerals, and protein for chimpanzees. To eat termites, chimpanzees need to use relatively thin probes to fish the termites out of the mounds where they live. The inside of termite mounds is made up of winding tunnels, which require tools that can navigate their complex structure.
Chimpanzees do not simply use any stick or plant that is available. Instead, they consciously choose plants with flexibility, specifically selecting materials that enhance their foraging effectiveness. Researchers hypothesized that using flexible tools would be more effective for chimpanzees at fishing out termites than using rigid sticks.
Using a portable mechanical tester, researchers measured the stiffness of various materials and discovered that chimpanzees prefer plants that are 2.75 times more flexible than those they ignore, indicating a sophisticated understanding of material properties, reported Discover Wildlife. First author Alejandra Pascual-Garrido took the tester to Gombe and measured how much force it took to bend plant materials used by the chimpanzees compared to plant materials that were available but never used. Among plants growing near termite mounds, those that showed obvious signs of regular use by the chimpanzees produced more flexible tools than nearby plants that showed no signs of use.
"This is the first comprehensive evidence that wild chimpanzees select tool materials for termite fishing based on specific mechanical properties," stated Dr. Pascual-Garrido, Research Affiliate at the School of Anthropology and Museum Ethnography, University of Oxford. "This novel approach, which combines biomechanics with animal behaviour, helps us better understand the cognitive processes behind chimpanzee tool construction and how they evaluate and select materials based on functional properties."
The study suggests that wild chimpanzees may possess a kind of "folk physics," an intuitive comprehension of material properties that helps them choose the best tools for the job. Chimpanzees have an innate understanding of material properties, which may be deeply rooted in their tool-making culture.
"This finding has important implications for understanding how humans might have evolved their remarkable tool-using abilities," explained Adam van Casteren, from the Department of Human Origins at the Max Planck Institute for Evolutionary Anthropology. "While perishable materials like wood rarely survive in the archaeological record, the mechanical principles behind effective tool construction and use remain constant across species and time," he added.
By studying how chimpanzees select materials based on specific structural and mechanical properties, researchers can better understand the physical constraints and requirements that would have applied to early human tool use. The findings have important implications for understanding the technical abilities associated with the making of perishable tools, a highly unknown aspect of human technological evolution.
Certain plant species, such as Grewia spp., constitute tool material for termite-fishing chimpanzee communities living up to 5,000 kilometers away from Gombe, indicating the universality of their "engineering standards." The mechanics of these plant materials could be a foundation for such ubiquitous preferences among chimpanzees. The findings raise important questions about how this knowledge is learned, maintained, and transmitted across generations.
Researchers question whether similar mechanical principles determine chimpanzees' selection of materials for making other foraging tools, such as those used for eating ants or harvesting honey. Using a comparative functional framework provides new insights into aspects of early technology that are not preserved in the archaeological record.
Dr. Pascual-Garrido studied the raw materials used in chimpanzee tools in Gombe for more than a decade. Young chimpanzees may learn tool-making knowledge by observing and using their mothers' tools, but they also likely test and choose materials independently.
The article was written with the assistance of a news analysis system.