Chimpanzees don't just randomly use sticks to fish for termites. A study reveals they meticulously select plants with ideal mechanical properties, demonstrating an intuitive understanding of physics.
This discovery, published in
iScience, sheds light on the cognitive abilities of our closest relatives. Conducted in Gombe National Park in Tanzania, it shows that these primates optimize their tools based on flexibility and strength criteria—a behavior reminiscent of early human innovations.
Tailored material selection
Gombe chimpanzees precisely select plants like
Grewia forbesii or
Uvaria angolensis, whose stems offer optimal flexibility. This property, measured by researchers, allows the tools to follow the winding contours of termite tunnels without breaking during repeated use.
The study found that materials ignored by the primates were on average 175% stiffer. Even more remarkably, within the same plant species, chimpanzees systematically targeted individuals whose stems provided the best balance between flexibility and durability. This meticulous selection goes beyond mere chance.
After choosing the raw material, chimpanzees carefully shape their tools: stripping bark, adjusting length (11-12 inches) and diameter (0.08-0.16 inches). These standardized modifications, observed across hundreds of tools, indicate genuine technical mastery passed down through generations.
Engineering rooted in evolution
The most striking discovery concerns the universality of these practices: chimpanzee communities separated by 3,100 miles use the same plant species for their tools. This cultural convergence suggests their selection is based on objective mechanical principles, not just local habits.
Researchers see this as evidence of "intuitive physics"—an innate understanding of material properties that likely guided our hominid ancestors as well. Young chimpanzees acquire this knowledge by observing their mothers, sometimes reusing their tools, creating a socially transmitted technological tradition.
This discovery illuminates a little-known aspect of human evolution: before stone tools, our ancestors likely developed similar expertise with perishable materials. Chimpanzees thus offer us a living window into the deep origins of technical ingenuity, long before the first lithic tools appeared.
Article author: Cédric DEPOND