We knew chimps were smart. We knew they use and make tools. But a new study has highlighted the extent and ability of chimpanzees’ engineering ability — and it’s stunning.
In the heart of Tanzania’s Gombe Stream National Park, chimps are constantly looking for ways to “fish” termites from their mounds. And they don’t just grab the nearest twig. They select plant materials based on how well they bend and flex — choosing options that are structurally ideal for the tight, winding tunnels of termite mounds. According to the researchers, chimps show an intuitive grasp of mechanical properties that rivals early human ingenuity. In other words, they seem to have a good grasp of “folk physics.”
An eye for materials
The chimpanzees of Gombe Stream National Park have long been studied by researchers. First made famous by Jane Goodall in the 1960s, they were the first wild chimps observed using tools — thrusting twigs into termite mounds to extract insects. But what continues to set the Gombe chimps apart is not just their tool use, but the sophistication behind it.
Termite fishing may sound like a niche pastime, but for Gombe’s chimpanzees, it’s important business. They get a lot of protein from these termites. To extract the nutritious insects from their labyrinthine mud mounds, chimpanzees insert thin plant probes into narrow tunnels. But not just any twig will do. They need twigs with the right mechanical properties: flexible enough to be maneuverable in the termite mound but also sturdy enough so that it doesn’t break.
A team of researchers, led by Alejandra Pascual-Garrido at the University of Oxford, carried out a meticulous investigation to determine whether chimpanzees are choosy about their raw materials — and, if so, why. They brought a mechanical tester into the forest to measure the bending stiffness of 544 plant samples, including species both used and ignored by the chimpanzees.
The results were telling. Plants selected by chimpanzees to make tools were significantly more flexible — on average, 175% less rigid — than nearby plants that were never touched. Even within the same species, chimpanzees seemed to return to specific individuals whose stems offered just the right balance of strength and flexibility.
“This is the first comprehensive evidence that wild chimpanzees select tool materials for termite fishing based on specific mechanical properties,” says Alejandra Pascual-Garrido, who has been studying the raw materials used in chimpanzee tools in Gombe for more than a decade.
The mechanics the termite fishing tool
There’s no way chimps do this by accident or at random. They exhibit a specific preference for the right type of tool. To understand why flexibility matters, imagine poking a stick through a twisty straw. A stiff rod would jam. But a pliable probe? It snakes through, following the curves, and emerges coated in termites.
The researchers quantified this flexibility using a property known as flexural rigidity (EI). Tools made from preferred plants — like Monanthotaxis poggei, Grewia forbesii, and Uvaria angolensis — had the lowest EI values. These materials bend easily but snap back into shape, ideal for repeated use. Bark, in particular, stood out: it had both low rigidity and low material stiffness (E), making it the tool of choice for chimpanzees across diverse regions, from Tanzania to Senegal.
“The mechanics of these plant tissues appear to contribute to the ubiquity of their selection,” the researchers wrote in their paper, published in iScience. It’s not just that certain plants are used more often—they’re used for good reason. “Our research therefore extends the technological knowhow of wild chimpanzees to their toolmaking behavior.”
They also don’t just grab twigs and use them. They improve their tools, stripping the leaves, trimming it to a size that matches the tunnel’s diameter. The average tool measures about 28–30 cm in length and 2–4 mm in diameter, optimized for termite mounds constructed by Macrotermes.
“Our findings provide insights into the technical skills associated with perishable artefact-making and raise questions about how this knowledge is learnt and culturally transmitted.”
How do they know this?
Notably, chimps from thousands of kilometers away also use tools, which suggests that engineering may be deeply rooted in chimpanzee tool-making culture.
Could chimpanzees be intuitively selecting materials with lower elastic moduli — properties that aren’t directly visible or felt, but manifest through trial, success, and learning? “The stiffness of a material is not a very salient property,” the authors note, “and cannot be assessed by how a tool behaves unlike EI.” But they might be selecting low-stiffness materials indirectly — by choosing bark, for example, which also allows for thicker tools with better termite-catching surfaces.
But there’s also a degree of learning, teaching, and tradition.
mounds in which the probe tools are inserted. (C) A probe tool left inserted into a Macrotermes mound, white arrow highlights the inserted end. Image from the study.
At Gombe, young chimpanzees watch their mothers fish for termites. They copy the technique. Sometimes they even reuse abandoned tools. Over time, these seemingly minor decisions — where to find a twig, how to shape it, when it’s not good enough — become embedded in the culture. “Technical skills may be obtained through trial-and-error learning but social learning may also contribute,” the study reads.
Chimpanzees across Africa exhibit regional tool traditions, and this study suggests that material mechanics may help explain those differences. One community may prefer bark, another vines, but in both cases, the chosen materials show the same mechanical advantages. It’s not just habit — it’s function.
A mirror for our own evolution
Chimps seem to craft tools not just with brute instinct, but with an eye for physics. This is a striking find: our closest relatives are intuitive engineers, which is very similar to our own ancestors.
“This finding has important implications for understanding how humans might have evolved their remarkable tool using abilities,” explains Adam van Casteren, Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, a specialist in biomechanics and evolutionary biology. “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.”
Chimpanzees may not draft blueprints or build bridges (yet). But they exhibit a kind of ancestral engineering. They probe the world with purpose. And in doing so, they illuminate the ancient roots of a distinctly human trait: the urge to shape the environment, one tool at a time.
Journal Reference: Alejandra Pascual-Garrido, Susana Carvalho, Deus Mjungu, Ellen Schulz-Kornas, Adam Van Casteren. Engineering skills in the manufacture of tools by wild chimpanzees. iScience, 2025 DOI: 10.1016/j.isci.2025.112158
